diff --git a/a1/ec897216fa/0/content_hash.txt b/a1/ec897216fa/0/content_hash.txt
new file mode 100644
index 00000000..d50d635a
--- /dev/null
+++ b/a1/ec897216fa/0/content_hash.txt
@@ -0,0 +1 @@
+sha256:1dcb6843168359e9b2654c83358578039372b70f58b982b538a063215bac9742
\ No newline at end of file
diff --git a/a1/ec897216fa/0/full.jsonl b/a1/ec897216fa/0/full.jsonl
new file mode 100644
index 00000000..981e2cf4
--- /dev/null
+++ b/a1/ec897216fa/0/full.jsonl
@@ -0,0 +1,68 @@
+{"type":"file-history-snapshot","messageId":"f2ec2906-586d-4c3d-960c-e27bb83c3602","snapshot":{"messageId":"f2ec2906-586d-4c3d-960c-e27bb83c3602","trackedFileBackups":{},"timestamp":"2026-03-28T05:49:37.201Z"},"isSnapshotUpdate":false}
+{"parentUuid":null,"isSidechain":false,"promptId":"9d854512-37f2-478e-99b4-764236bbaa5a","type":"user","message":{"role":"user","content":"<local-command-caveat>Caveat: The messages below were generated by the user while running local commands. DO NOT respond to these messages or otherwise consider them in your response unless the user explicitly asks you to.</local-command-caveat>"},"isMeta":true,"uuid":"0cc28696-ceb5-4907-9849-c5441cf70f2b","timestamp":"2026-03-28T05:49:37.201Z","userType":"external","entrypoint":"cli","cwd":"/Users/jan/prg/ClusterCockpit/cc-backend","sessionId":"88c65864-3f29-4b06-bbe1-7fab0c4a0142","version":"2.1.86","gitBranch":"hotfix"}
+{"parentUuid":"0cc28696-ceb5-4907-9849-c5441cf70f2b","isSidechain":false,"promptId":"9d854512-37f2-478e-99b4-764236bbaa5a","type":"user","message":{"role":"user","content":"<command-name>/clear</command-name>\n            <command-message>clear</command-message>\n            <command-args></command-args>"},"uuid":"f2ec2906-586d-4c3d-960c-e27bb83c3602","timestamp":"2026-03-28T05:49:37.089Z","userType":"external","entrypoint":"cli","cwd":"/Users/jan/prg/ClusterCockpit/cc-backend","sessionId":"88c65864-3f29-4b06-bbe1-7fab0c4a0142","version":"2.1.86","gitBranch":"hotfix"}
+{"parentUuid":"f2ec2906-586d-4c3d-960c-e27bb83c3602","isSidechain":false,"type":"system","subtype":"local_command","content":"<local-command-stdout></local-command-stdout>","level":"info","timestamp":"2026-03-28T05:49:37.201Z","uuid":"46ea6882-e5f1-434f-abd9-296a38307798","isMeta":false,"userType":"external","entrypoint":"cli","cwd":"/Users/jan/prg/ClusterCockpit/cc-backend","sessionId":"88c65864-3f29-4b06-bbe1-7fab0c4a0142","version":"2.1.86","gitBranch":"hotfix"}
+{"type":"file-history-snapshot","messageId":"74ed16e4-8db6-463c-b7d3-9997b0c0eab5","snapshot":{"messageId":"74ed16e4-8db6-463c-b7d3-9997b0c0eab5","trackedFileBackups":{},"timestamp":"2026-03-28T05:50:19.846Z"},"isSnapshotUpdate":false}
+{"parentUuid":"46ea6882-e5f1-434f-abd9-296a38307798","isSidechain":false,"promptId":"9eaa6266-c81c-429f-b399-58d96fa3743c","type":"user","message":{"role":"user","content":"After a regular checkpoint the following log warning is writte nfor all nodes:  [WARNING]  walCheckpoint.go:343: [METRICSTORE]> WAL rotation skipped for var/metric-checkpoints/fritz/f0748 (channel full)\nMar 28 06:39:43 monitoring cc-backend[45645]: [WARNING]  walCheckpoint.go:343: [METRICSTORE]> WAL rotation skipped for var/metric-checkpoints/fritz/f2263 (channel full)\nMar 28 06:39:43 monitoring cc-backend[45645]: [WARNING]  walCheckpoint.go:343: [METRICSTORE]> WAL rotation skipped for var/metric-checkpoints/fritz/f0481 (channel full)\nMar 28 06:39:43 monitoring cc-backend[45645]: [WARNING]  walCheckpoint.go:343: [METRICSTORE]> WAL rotation skipped for var/metric-checkpoints/fritz/f0708 (channel full)\nMar 28 06:39:43 monitoring cc-backend[45645]: [WARNING]  walCheckpoint.go:343: [METRICSTORE]> WAL rotation skipped for var/metric-checkpoints/fritz/f0373 (channel full) . Investigate and issue and suggest fixes."},"uuid":"74ed16e4-8db6-463c-b7d3-9997b0c0eab5","timestamp":"2026-03-28T05:50:19.233Z","permissionMode":"plan","userType":"external","entrypoint":"cli","cwd":"/Users/jan/prg/ClusterCockpit/cc-backend","sessionId":"88c65864-3f29-4b06-bbe1-7fab0c4a0142","version":"2.1.86","gitBranch":"hotfix","slug":"warm-enchanting-clarke"}
+{"parentUuid":"74ed16e4-8db6-463c-b7d3-9997b0c0eab5","isSidechain":false,"message":{"model":"claude-opus-4-6","id":"msg_015LNoebWS4Neq3MHCHh5kno","type":"message","role":"assistant","content":[{"type":"thinking","thinking":"","signature":"EpECClkIDBgCKkAhKcM/6Q8b85rMdIjiX+bjwW1Br/dLRI3r5gcga2LDmz8LHLhwWvHVHVwtAIlURZCxmT20RM6EfkkWy1ItUrTeMg9jbGF1ZGUtb3B1cy00LTY4ABIMeWy+TED2aJLEufjyGgz/PXQEVFH3zCWMZsYiMBvabFt2IJeRwAmVPQhs+SypWS9ijbdxZnKppooEpr1KQNMLfuiFPHbFXGoTdYpIQSpmeAnKkLjFfexP2QhpWmeClcxEJ5rQF9fYB8JrTNj2TIYy82zq4y/IoLInK9hLDHThDaG+TKHf+hESsZG/VDpGEfrR1aDN9xwQajwliL6NeFXu4w1yla+9vQ0lf3XbAOtgOtwTQR+UGAE="}],"stop_reason":null,"stop_sequence":null,"usage":{"input_tokens":3,"cache_creation_input_tokens":9579,"cache_read_input_tokens":11336,"cache_creation":{"ephemeral_5m_input_tokens":0,"ephemeral_1h_input_tokens":9579},"output_tokens":58,"service_tier":"standard","inference_geo":"not_available"}},"requestId":"req_011CZUxLNRSfMYB4JVsAmZ96","type":"assistant","uuid":"091cb7f7-a1bf-4890-9867-03026cf9d621","timestamp":"2026-03-28T05:50:22.311Z","userType":"external","entrypoint":"cli","cwd":"/Users/jan/prg/ClusterCockpit/cc-backend","sessionId":"88c65864-3f29-4b06-bbe1-7fab0c4a0142","version":"2.1.86","gitBranch":"hotfix","slug":"warm-enchanting-clarke"}
+{"parentUuid":"091cb7f7-a1bf-4890-9867-03026cf9d621","isSidechain":false,"message":{"model":"claude-opus-4-6","id":"msg_015LNoebWS4Neq3MHCHh5kno","type":"message","role":"assistant","content":[{"type":"tool_use","id":"toolu_01KVS4qSDGAKxvaAakfyRThJ","name":"Read","input":{"file_path":"/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go"},"caller":{"type":"direct"}}],"stop_reason":"tool_use","stop_sequence":null,"usage":{"input_tokens":3,"cache_creation_input_tokens":9579,"cache_read_input_tokens":11336,"output_tokens":113,"server_tool_use":{"web_search_requests":0,"web_fetch_requests":0},"service_tier":"standard","cache_creation":{"ephemeral_1h_input_tokens":9579,"ephemeral_5m_input_tokens":0},"inference_geo":"","iterations":[],"speed":"standard"}},"requestId":"req_011CZUxLNRSfMYB4JVsAmZ96","type":"assistant","uuid":"21c1f21c-ecfd-4e30-b920-33985707e54c","timestamp":"2026-03-28T05:50:23.186Z","userType":"external","entrypoint":"cli","cwd":"/Users/jan/prg/ClusterCockpit/cc-backend","sessionId":"88c65864-3f29-4b06-bbe1-7fab0c4a0142","version":"2.1.86","gitBranch":"hotfix","slug":"warm-enchanting-clarke"}
+{"parentUuid":"21c1f21c-ecfd-4e30-b920-33985707e54c","isSidechain":false,"promptId":"9eaa6266-c81c-429f-b399-58d96fa3743c","type":"user","message":{"role":"user","content":[{"type":"tool_result","content":"File content (10285 tokens) exceeds maximum allowed tokens (10000). Use offset and limit parameters to read specific portions of the file, or search for specific content instead of reading the whole file.","is_error":true,"tool_use_id":"toolu_01KVS4qSDGAKxvaAakfyRThJ"}]},"uuid":"357e3697-6cd3-4dcf-a6e0-3aabf8749f53","timestamp":"2026-03-28T05:50:23.478Z","toolUseResult":"Error: File content (10285 tokens) exceeds maximum allowed tokens (10000). Use offset and limit parameters to read specific portions of the file, or search for specific content instead of reading the whole file.","sourceToolAssistantUUID":"21c1f21c-ecfd-4e30-b920-33985707e54c","userType":"external","entrypoint":"cli","cwd":"/Users/jan/prg/ClusterCockpit/cc-backend","sessionId":"88c65864-3f29-4b06-bbe1-7fab0c4a0142","version":"2.1.86","gitBranch":"hotfix","slug":"warm-enchanting-clarke"}
+{"parentUuid":"357e3697-6cd3-4dcf-a6e0-3aabf8749f53","isSidechain":false,"message":{"model":"claude-opus-4-6","id":"msg_01JkKHRBwjbBRf5e73wwvfy2","type":"message","role":"assistant","content":[{"type":"tool_use","id":"toolu_01Lgi4dn9E5jhe5iRikfwZGs","name":"Grep","input":{"pattern":"WAL rotation skipped|channel full|RotateWAL|walRotation","path":"/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore","output_mode":"content","-C":5},"caller":{"type":"direct"}}],"stop_reason":"tool_use","stop_sequence":null,"usage":{"input_tokens":1,"cache_creation_input_tokens":175,"cache_read_input_tokens":20915,"output_tokens":146,"server_tool_use":{"web_search_requests":0,"web_fetch_requests":0},"service_tier":"standard","cache_creation":{"ephemeral_1h_input_tokens":175,"ephemeral_5m_input_tokens":0},"inference_geo":"","iterations":[],"speed":"standard"}},"requestId":"req_011CZUxLdouSTEDcdntN9wyA","type":"assistant","uuid":"d931a391-525f-40e5-ac1e-930852fd21af","timestamp":"2026-03-28T05:50:26.347Z","userType":"external","entrypoint":"cli","cwd":"/Users/jan/prg/ClusterCockpit/cc-backend","sessionId":"88c65864-3f29-4b06-bbe1-7fab0c4a0142","version":"2.1.86","gitBranch":"hotfix","slug":"warm-enchanting-clarke"}
+{"parentUuid":"d931a391-525f-40e5-ac1e-930852fd21af","isSidechain":false,"promptId":"9eaa6266-c81c-429f-b399-58d96fa3743c","type":"user","message":{"role":"user","content":[{"tool_use_id":"toolu_01Lgi4dn9E5jhe5iRikfwZGs","type":"tool_result","content":"pkg/metricstore/checkpoint.go-134-\t\t\t\t\t\tcclog.Infof(\"[METRICSTORE]> done: %d binary snapshot files created\", n)\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-135-\t\t\t\t\t\tlastCheckpointMu.Lock()\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-136-\t\t\t\t\t\tlastCheckpoint = now\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-137-\t\t\t\t\t\tlastCheckpointMu.Unlock()\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-138-\t\t\t\t\t\t// Rotate WAL files for successfully checkpointed hosts.\npkg/metricstore/checkpoint.go:139:\t\t\t\t\t\tRotateWALFiles(hostDirs)\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-140-\t\t\t\t\t}\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-141-\t\t\t\t} else {\npkg/metricstore/checkpoint.go-142-\t\t\t\t\tn, err := ms.ToCheckpoint(Keys.Checkpoints.RootDir, from.Unix(), now.Unix())\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-143-\t\t\t\t\tif err != nil {\npkg/metricstore/checkpoint.go-144-\t\t\t\t\t\tcclog.Errorf(\"[METRICSTORE]> checkpointing failed: %s\", err.Error())\n--\npkg/metricstore/lineprotocol.go-360-\t\t\t\tSelector:   append([]string{}, st.selector...),\npkg/metricstore/lineprotocol.go-361-\t\t\t\tValue:      metric.Value,\npkg/metricstore/lineprotocol.go-362-\t\t\t\tTimestamp:  time,\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/lineprotocol.go-363-\t\t\t}\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/lineprotocol.go-364-\t\t\tif !SendWALMessage(msg) {\npkg/metricstore/lineprotocol.go:365:\t\t\t\t// WAL shard channel full — metric is written to memory store but not WAL.\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/lineprotocol.go-366-\t\t\t\t// Next binary snapshot will capture it.\npkg/metricstore/lineprotocol.go-367-\t\t\t\tif dropped := walDropped.Add(1); dropped%10000 == 1 {\npkg/metricstore/lineprotocol.go:368:\t\t\t\t\tcclog.Warnf(\"[METRICSTORE]> WAL shard channel full, dropped %d messages (data safe in memory, next snapshot will capture)\", dropped)\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/lineprotocol.go-369-\t\t\t\t}\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/lineprotocol.go-370-\t\t\t}\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/lineprotocol.go-371-\t\t}\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/lineprotocol.go-372-\npkg/metricstore/lineprotocol.go-373-\t\tif err := ms.WriteToLevel(lvl, st.selector, time, []Metric{metric}); err != nil {\n--\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-346-// flushed and closed before checkpoint writes begin.\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-347-func WaitForWALStagingDrain() {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-348-\twalStagingWg.Wait()\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-349-}\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-350-\npkg/metricstore/walCheckpoint.go:351:// RotateWALFiles sends rotation requests for the given host directories\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-352-// and blocks until all rotations complete. Each request is routed to the\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-353-// shard that owns the host directory.\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-354-//\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-355-// If shutdown is in progress (WAL staging goroutines may have exited),\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-356-// rotation is skipped to avoid deadlocking on abandoned channels.\npkg/metricstore/walCheckpoint.go:357:func RotateWALFiles(hostDirs []string) {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-358-\tif walShardRotateChs == nil || walShuttingDown.Load() {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-359-\t\treturn\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-360-\t}\npkg/metricstore/walCheckpoint.go-361-\tdones := make([]chan struct{}, 0, len(hostDirs))\npkg/metricstore/walCheckpoint.go-362-\tfor _, dir := range hostDirs {\n--\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-365-\t\tselect {\npkg/metricstore/walCheckpoint.go-366-\t\tcase walShardRotateChs[shard] <- walRotateReq{hostDir: dir, done: done}:\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-367-\t\t\tdones = append(dones, done)\npkg/metricstore/walCheckpoint.go-368-\t\tdefault:\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-369-\t\t\t// Channel full or goroutine not consuming — skip this host.\npkg/metricstore/walCheckpoint.go:370:\t\t\tcclog.Warnf(\"[METRICSTORE]> WAL rotation skipped for %s (channel full)\", dir)\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-371-\t\t}\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-372-\t}\npkg/metricstore/walCheckpoint.go-373-\tfor _, done := range dones {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-374-\t\tselect {\npkg/metricstore/walCheckpoint.go-375-\t\tcase <-done:\n--\npkg/metricstore/walCheckpoint.go-387-\tnode := path.Base(hostDir)\npkg/metricstore/walCheckpoint.go-388-\tcluster := path.Base(path.Dir(hostDir))\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-389-\treturn walShardIndex(cluster, node)\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-390-}\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-391-\npkg/metricstore/walCheckpoint.go:392:// RotateWALFiles sends rotation requests for the given host directories\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-393-// and blocks until all rotations complete.\npkg/metricstore/walCheckpoint.go:394:func RotateWALFilesAfterShutdown(hostDirs []string) {\npkg/metricstore/walCheckpoint.go-395-\tfor _, dir := range hostDirs {\npkg/metricstore/walCheckpoint.go-396-\t\twalPath := path.Join(dir, \"current.wal\")\npkg/metricstore/walCheckpoint.go-397-\t\tif err := os.Remove(walPath); err != nil && !os.IsNotExist(err) {\npkg/metricstore/walCheckpoint.go-398-\t\t\tcclog.Errorf(\"[METRICSTORE]> WAL: remove %s: %v\", walPath, err)\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-399-\t\t}"}]},"uuid":"c4514dd1-6442-4852-830d-9031945f388a","timestamp":"2026-03-28T05:50:26.364Z","toolUseResult":{"mode":"content","numFiles":0,"filenames":[],"content":"pkg/metricstore/checkpoint.go-134-\t\t\t\t\t\tcclog.Infof(\"[METRICSTORE]> done: %d binary snapshot files created\", n)\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-135-\t\t\t\t\t\tlastCheckpointMu.Lock()\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-136-\t\t\t\t\t\tlastCheckpoint = now\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-137-\t\t\t\t\t\tlastCheckpointMu.Unlock()\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-138-\t\t\t\t\t\t// Rotate WAL files for successfully checkpointed hosts.\npkg/metricstore/checkpoint.go:139:\t\t\t\t\t\tRotateWALFiles(hostDirs)\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-140-\t\t\t\t\t}\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-141-\t\t\t\t} else {\npkg/metricstore/checkpoint.go-142-\t\t\t\t\tn, err := ms.ToCheckpoint(Keys.Checkpoints.RootDir, from.Unix(), now.Unix())\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-143-\t\t\t\t\tif err != nil {\npkg/metricstore/checkpoint.go-144-\t\t\t\t\t\tcclog.Errorf(\"[METRICSTORE]> checkpointing failed: %s\", err.Error())\n--\npkg/metricstore/lineprotocol.go-360-\t\t\t\tSelector:   append([]string{}, st.selector...),\npkg/metricstore/lineprotocol.go-361-\t\t\t\tValue:      metric.Value,\npkg/metricstore/lineprotocol.go-362-\t\t\t\tTimestamp:  time,\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/lineprotocol.go-363-\t\t\t}\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/lineprotocol.go-364-\t\t\tif !SendWALMessage(msg) {\npkg/metricstore/lineprotocol.go:365:\t\t\t\t// WAL shard channel full — metric is written to memory store but not WAL.\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/lineprotocol.go-366-\t\t\t\t// Next binary snapshot will capture it.\npkg/metricstore/lineprotocol.go-367-\t\t\t\tif dropped := walDropped.Add(1); dropped%10000 == 1 {\npkg/metricstore/lineprotocol.go:368:\t\t\t\t\tcclog.Warnf(\"[METRICSTORE]> WAL shard channel full, dropped %d messages (data safe in memory, next snapshot will capture)\", dropped)\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/lineprotocol.go-369-\t\t\t\t}\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/lineprotocol.go-370-\t\t\t}\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/lineprotocol.go-371-\t\t}\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/lineprotocol.go-372-\npkg/metricstore/lineprotocol.go-373-\t\tif err := ms.WriteToLevel(lvl, st.selector, time, []Metric{metric}); err != nil {\n--\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-346-// flushed and closed before checkpoint writes begin.\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-347-func WaitForWALStagingDrain() {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-348-\twalStagingWg.Wait()\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-349-}\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-350-\npkg/metricstore/walCheckpoint.go:351:// RotateWALFiles sends rotation requests for the given host directories\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-352-// and blocks until all rotations complete. Each request is routed to the\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-353-// shard that owns the host directory.\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-354-//\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-355-// If shutdown is in progress (WAL staging goroutines may have exited),\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-356-// rotation is skipped to avoid deadlocking on abandoned channels.\npkg/metricstore/walCheckpoint.go:357:func RotateWALFiles(hostDirs []string) {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-358-\tif walShardRotateChs == nil || walShuttingDown.Load() {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-359-\t\treturn\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-360-\t}\npkg/metricstore/walCheckpoint.go-361-\tdones := make([]chan struct{}, 0, len(hostDirs))\npkg/metricstore/walCheckpoint.go-362-\tfor _, dir := range hostDirs {\n--\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-365-\t\tselect {\npkg/metricstore/walCheckpoint.go-366-\t\tcase walShardRotateChs[shard] <- walRotateReq{hostDir: dir, done: done}:\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-367-\t\t\tdones = append(dones, done)\npkg/metricstore/walCheckpoint.go-368-\t\tdefault:\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-369-\t\t\t// Channel full or goroutine not consuming — skip this host.\npkg/metricstore/walCheckpoint.go:370:\t\t\tcclog.Warnf(\"[METRICSTORE]> WAL rotation skipped for %s (channel full)\", dir)\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-371-\t\t}\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-372-\t}\npkg/metricstore/walCheckpoint.go-373-\tfor _, done := range dones {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-374-\t\tselect {\npkg/metricstore/walCheckpoint.go-375-\t\tcase <-done:\n--\npkg/metricstore/walCheckpoint.go-387-\tnode := path.Base(hostDir)\npkg/metricstore/walCheckpoint.go-388-\tcluster := path.Base(path.Dir(hostDir))\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-389-\treturn walShardIndex(cluster, node)\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-390-}\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-391-\npkg/metricstore/walCheckpoint.go:392:// RotateWALFiles sends rotation requests for the given host directories\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-393-// and blocks until all rotations complete.\npkg/metricstore/walCheckpoint.go:394:func RotateWALFilesAfterShutdown(hostDirs []string) {\npkg/metricstore/walCheckpoint.go-395-\tfor _, dir := range hostDirs {\npkg/metricstore/walCheckpoint.go-396-\t\twalPath := path.Join(dir, \"current.wal\")\npkg/metricstore/walCheckpoint.go-397-\t\tif err := os.Remove(walPath); err != nil && !os.IsNotExist(err) {\npkg/metricstore/walCheckpoint.go-398-\t\t\tcclog.Errorf(\"[METRICSTORE]> WAL: remove %s: %v\", walPath, err)\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-399-\t\t}","numLines":70},"sourceToolAssistantUUID":"d931a391-525f-40e5-ac1e-930852fd21af","userType":"external","entrypoint":"cli","cwd":"/Users/jan/prg/ClusterCockpit/cc-backend","sessionId":"88c65864-3f29-4b06-bbe1-7fab0c4a0142","version":"2.1.86","gitBranch":"hotfix","slug":"warm-enchanting-clarke"}
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+{"parentUuid":"27b689cc-aca8-469f-b4be-acb37c5a22e9","isSidechain":false,"promptId":"9eaa6266-c81c-429f-b399-58d96fa3743c","type":"user","message":{"role":"user","content":[{"tool_use_id":"toolu_018t7nzzks4F3CkqTZgPeEnz","type":"tool_result","content":"1\t// Copyright (C) NHR@FAU, University Erlangen-Nuremberg.\n2\t// All rights reserved. This file is part of cc-backend.\n3\t// Use of this source code is governed by a MIT-style\n4\t// license that can be found in the LICENSE file.\n5\t\n6\t// Package metricstore provides walCheckpoint.go: WAL-based checkpoint implementation.\n7\t//\n8\t// This replaces the Avro shadow tree with an append-only Write-Ahead Log (WAL)\n9\t// per host, eliminating the extra memory overhead of the AvroStore and providing\n10\t// truly continuous (per-write) crash safety.\n11\t//\n12\t// # Architecture\n13\t//\n14\t//\tMetric write (DecodeLine)\n15\t//\t      │\n16\t//\t      ├─► WriteToLevel()    → main MemoryStore (unchanged)\n17\t//\t      │\n18\t//\t      └─► WALMessages channel\n19\t//\t               │\n20\t//\t               ▼\n21\t//\t        WALStaging goroutine\n22\t//\t               │\n23\t//\t               ▼\n24\t//\t        checkpoints/cluster/host/current.wal  (append-only, binary)\n25\t//\n26\t//\tPeriodic checkpoint (Checkpointing goroutine):\n27\t//\t  1. Write <timestamp>.bin snapshot (column-oriented, from main tree)\n28\t//\t  2. Signal WALStaging to truncate current.wal per host\n29\t//\n30\t//\tOn restart (FromCheckpoint):\n31\t//\t  1. Load most recent <timestamp>.bin snapshot\n32\t//\t  2. Replay current.wal (overwrite-safe: buffer.write handles duplicate timestamps)\n33\t//\n34\t// # WAL Record Format\n35\t//\n36\t//\t[4B magic 0xCC1DA7A1][4B payload_len][payload][4B CRC32]\n37\t//\n38\t//\tpayload:\n39\t//\t  [8B timestamp int64]\n40\t//\t  [2B metric_name_len uint16][N metric name bytes]\n41\t//\t  [1B selector_count uint8]\n42\t//\t  per selector: [1B selector_len uint8][M selector bytes]\n43\t//\t  [4B value float32 bits]\n44\t//\n45\t// # Binary Snapshot Format\n46\t//\n47\t//\t[4B magic 0xCC5B0001][8B from int64][8B to int64]\n48\t//\tLevel tree (recursive):\n49\t//\t  [4B num_metrics uint32]\n50\t//\t  per metric:\n51\t//\t    [2B name_len uint16][N name bytes]\n52\t//\t    [8B frequency int64][8B start int64]\n53\t//\t    [4B num_values uint32][num_values × 4B float32]\n54\t//\t  [4B num_children uint32]\n55\t//\t  per child: [2B name_len uint16][N name bytes] + Level (recursive)\n56\tpackage metricstore\n57\t\n58\timport (\n59\t\t\"bufio\"\n60\t\t\"context\"\n61\t\t\"encoding/binary\"\n62\t\t\"fmt\"\n63\t\t\"hash/crc32\"\n64\t\t\"hash/fnv\"\n65\t\t\"io\"\n66\t\t\"math\"\n67\t\t\"os\"\n68\t\t\"path\"\n69\t\t\"strings\"\n70\t\t\"sync\"\n71\t\t\"sync/atomic\"\n72\t\t\"time\"\n73\t\n74\t\tcclog \"github.com/ClusterCockpit/cc-lib/v2/ccLogger\"\n75\t\t\"github.com/ClusterCockpit/cc-lib/v2/schema\"\n76\t)\n77\t\n78\t// Magic numbers for binary formats.\n79\tconst (\n80\t\twalFileMagic   = uint32(0xCC1DA701) // WAL file header magic\n81\t\twalRecordMagic = uint32(0xCC1DA7A1) // WAL record magic\n82\t\tsnapFileMagic  = uint32(0xCC5B0001) // Binary snapshot magic\n83\t)\n84\t\n85\t// walShardChs holds per-shard channels for WAL messages.\n86\t// Initialized by WALStaging; nil when WAL is not active.\n87\tvar walShardChs []chan *WALMessage\n88\t\n89\t// walShardRotateChs holds per-shard channels for WAL rotation requests.\n90\tvar walShardRotateChs []chan walRotateReq\n91\t\n92\t// walNumShards stores the number of shards (set during WALStaging init).\n93\tvar walNumShards int\n94\t\n95\t// walStagingWg tracks WALStaging goroutine exits for shutdown synchronization.\n96\tvar walStagingWg sync.WaitGroup\n97\t\n98\t// walShuttingDown is set before closing shard channels to prevent\n99\t// SendWALMessage from sending on a closed channel (which panics in Go).\n100\tvar walShuttingDown atomic.Bool"}]},"uuid":"6a8ab621-9191-42b8-ac89-e690aa523dc0","timestamp":"2026-03-28T05:50:28.559Z","toolUseResult":{"type":"text","file":{"filePath":"/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go","content":"// Copyright (C) NHR@FAU, University Erlangen-Nuremberg.\n// All rights reserved. This file is part of cc-backend.\n// Use of this source code is governed by a MIT-style\n// license that can be found in the LICENSE file.\n\n// Package metricstore provides walCheckpoint.go: WAL-based checkpoint implementation.\n//\n// This replaces the Avro shadow tree with an append-only Write-Ahead Log (WAL)\n// per host, eliminating the extra memory overhead of the AvroStore and providing\n// truly continuous (per-write) crash safety.\n//\n// # Architecture\n//\n//\tMetric write (DecodeLine)\n//\t      │\n//\t      ├─► WriteToLevel()    → main MemoryStore (unchanged)\n//\t      │\n//\t      └─► WALMessages channel\n//\t               │\n//\t               ▼\n//\t        WALStaging goroutine\n//\t               │\n//\t               ▼\n//\t        checkpoints/cluster/host/current.wal  (append-only, binary)\n//\n//\tPeriodic checkpoint (Checkpointing goroutine):\n//\t  1. Write <timestamp>.bin snapshot (column-oriented, from main tree)\n//\t  2. Signal WALStaging to truncate current.wal per host\n//\n//\tOn restart (FromCheckpoint):\n//\t  1. Load most recent <timestamp>.bin snapshot\n//\t  2. Replay current.wal (overwrite-safe: buffer.write handles duplicate timestamps)\n//\n// # WAL Record Format\n//\n//\t[4B magic 0xCC1DA7A1][4B payload_len][payload][4B CRC32]\n//\n//\tpayload:\n//\t  [8B timestamp int64]\n//\t  [2B metric_name_len uint16][N metric name bytes]\n//\t  [1B selector_count uint8]\n//\t  per selector: [1B selector_len uint8][M selector bytes]\n//\t  [4B value float32 bits]\n//\n// # Binary Snapshot Format\n//\n//\t[4B magic 0xCC5B0001][8B from int64][8B to int64]\n//\tLevel tree (recursive):\n//\t  [4B num_metrics uint32]\n//\t  per metric:\n//\t    [2B name_len uint16][N name bytes]\n//\t    [8B frequency int64][8B start int64]\n//\t    [4B num_values uint32][num_values × 4B float32]\n//\t  [4B num_children uint32]\n//\t  per child: [2B name_len uint16][N name bytes] + Level (recursive)\npackage metricstore\n\nimport (\n\t\"bufio\"\n\t\"context\"\n\t\"encoding/binary\"\n\t\"fmt\"\n\t\"hash/crc32\"\n\t\"hash/fnv\"\n\t\"io\"\n\t\"math\"\n\t\"os\"\n\t\"path\"\n\t\"strings\"\n\t\"sync\"\n\t\"sync/atomic\"\n\t\"time\"\n\n\tcclog \"github.com/ClusterCockpit/cc-lib/v2/ccLogger\"\n\t\"github.com/ClusterCockpit/cc-lib/v2/schema\"\n)\n\n// Magic numbers for binary formats.\nconst (\n\twalFileMagic   = uint32(0xCC1DA701) // WAL file header magic\n\twalRecordMagic = uint32(0xCC1DA7A1) // WAL record magic\n\tsnapFileMagic  = uint32(0xCC5B0001) // Binary snapshot magic\n)\n\n// walShardChs holds per-shard channels for WAL messages.\n// Initialized by WALStaging; nil when WAL is not active.\nvar walShardChs []chan *WALMessage\n\n// walShardRotateChs holds per-shard channels for WAL rotation requests.\nvar walShardRotateChs []chan walRotateReq\n\n// walNumShards stores the number of shards (set during WALStaging init).\nvar walNumShards int\n\n// walStagingWg tracks WALStaging goroutine exits for shutdown synchronization.\nvar walStagingWg sync.WaitGroup\n\n// walShuttingDown is set before closing shard channels to prevent\n// SendWALMessage from sending on a closed channel (which panics in Go).\nvar walShuttingDown atomic.Bool","numLines":100,"startLine":1,"totalLines":979}},"sourceToolAssistantUUID":"27b689cc-aca8-469f-b4be-acb37c5a22e9","userType":"external","entrypoint":"cli","cwd":"/Users/jan/prg/ClusterCockpit/cc-backend","sessionId":"88c65864-3f29-4b06-bbe1-7fab0c4a0142","version":"2.1.86","gitBranch":"hotfix","slug":"warm-enchanting-clarke"}
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+{"parentUuid":"dd405dc0-cf21-4c79-846a-ba0cad399945","isSidechain":false,"promptId":"9eaa6266-c81c-429f-b399-58d96fa3743c","type":"user","message":{"role":"user","content":[{"tool_use_id":"toolu_011wuAL5jiFgNrCep2gASmsM","type":"tool_result","content":"100\tvar walShuttingDown atomic.Bool\n101\t\n102\t// WALMessage represents a single metric write to be appended to the WAL.\n103\t// Cluster and Node are NOT stored in the WAL record (inferred from file path).\n104\ttype WALMessage struct {\n105\t\tMetricName string\n106\t\tCluster    string\n107\t\tNode       string\n108\t\tSelector   []string\n109\t\tValue      schema.Float\n110\t\tTimestamp  int64\n111\t}\n112\t\n113\t// walRotateReq requests WAL file rotation for a specific host directory.\n114\t// The done channel is closed by the WAL goroutine when rotation is complete.\n115\ttype walRotateReq struct {\n116\t\thostDir string\n117\t\tdone    chan struct{}\n118\t}\n119\t\n120\t// walFileState holds an open WAL file handle and buffered writer for one host directory.\n121\ttype walFileState struct {\n122\t\tf     *os.File\n123\t\tw     *bufio.Writer\n124\t\tdirty bool\n125\t\tsize  int64 // approximate bytes written (tracked from open + writes)\n126\t}\n127\t\n128\t// walFlushInterval controls how often dirty WAL files are flushed to disk.\n129\t// Decoupling flushes from message processing lets the consumer run at memory\n130\t// speed, amortizing syscall overhead across many writes.\n131\tconst walFlushInterval = 1 * time.Second\n132\t\n133\t// walShardIndex computes which shard a message belongs to based on cluster+node.\n134\t// Uses FNV-1a hash for fast, well-distributed mapping.\n135\tfunc walShardIndex(cluster, node string) int {\n136\t\th := fnv.New32a()\n137\t\th.Write([]byte(cluster))\n138\t\th.Write([]byte{0})\n139\t\th.Write([]byte(node))\n140\t\treturn int(h.Sum32()) % walNumShards\n141\t}\n142\t\n143\t// SendWALMessage routes a WAL message to the appropriate shard channel.\n144\t// Returns false if the channel is full or shutdown is in progress.\n145\tfunc SendWALMessage(msg *WALMessage) bool {\n146\t\tif walShardChs == nil || walShuttingDown.Load() {\n147\t\t\treturn false\n148\t\t}\n149\t\tshard := walShardIndex(msg.Cluster, msg.Node)\n150\t\tselect {\n151\t\tcase walShardChs[shard] <- msg:\n152\t\t\treturn true\n153\t\tdefault:\n154\t\t\treturn false\n155\t\t}\n156\t}\n157\t\n158\t// WALStaging starts N sharded background goroutines that receive WALMessage items\n159\t// and append binary WAL records to per-host current.wal files.\n160\t// Each shard owns a subset of hosts (determined by hash of cluster+node),\n161\t// parallelizing serialization and I/O while keeping per-host writes serial.\n162\tfunc WALStaging(wg *sync.WaitGroup, ctx context.Context) {\n163\t\tif Keys.Checkpoints.FileFormat == \"json\" {\n164\t\t\treturn\n165\t\t}\n166\t\n167\t\twalNumShards = max(Keys.NumWorkers, 1)\n168\t\tchBufSize := max(65536/walNumShards, 1024)\n169\t\n170\t\twalShardChs = make([]chan *WALMessage, walNumShards)\n171\t\twalShardRotateChs = make([]chan walRotateReq, walNumShards)\n172\t\n173\t\tfor i := range walNumShards {\n174\t\t\twalShardChs[i] = make(chan *WALMessage, chBufSize)\n175\t\t\twalShardRotateChs[i] = make(chan walRotateReq, 64)\n176\t\t}\n177\t\n178\t\tfor i := range walNumShards {\n179\t\t\tmsgCh := walShardChs[i]\n180\t\t\trotateCh := walShardRotateChs[i]\n181\t\n182\t\t\twalStagingWg.Add(1)\n183\t\t\twg.Go(func() {\n184\t\t\t\tdefer walStagingWg.Done()\n185\t\t\t\thostFiles := make(map[string]*walFileState)\n186\t\n187\t\t\t\tdefer func() {\n188\t\t\t\t\tfor _, ws := range hostFiles {\n189\t\t\t\t\t\tif ws.f != nil {\n190\t\t\t\t\t\t\tws.w.Flush()\n191\t\t\t\t\t\t\tws.f.Close()\n192\t\t\t\t\t\t}\n193\t\t\t\t\t}\n194\t\t\t\t}()\n195\t\n196\t\t\t\tgetOrOpenWAL := func(hostDir string) *walFileState {\n197\t\t\t\t\tws, ok := hostFiles[hostDir]\n198\t\t\t\t\tif ok {\n199\t\t\t\t\t\treturn ws"}]},"uuid":"2cef677e-d5dd-4c5e-8aa1-1f5aee7166a4","timestamp":"2026-03-28T05:50:31.804Z","toolUseResult":{"type":"text","file":{"filePath":"/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go","content":"var walShuttingDown atomic.Bool\n\n// WALMessage represents a single metric write to be appended to the WAL.\n// Cluster and Node are NOT stored in the WAL record (inferred from file path).\ntype WALMessage struct {\n\tMetricName string\n\tCluster    string\n\tNode       string\n\tSelector   []string\n\tValue      schema.Float\n\tTimestamp  int64\n}\n\n// walRotateReq requests WAL file rotation for a specific host directory.\n// The done channel is closed by the WAL goroutine when rotation is complete.\ntype walRotateReq struct {\n\thostDir string\n\tdone    chan struct{}\n}\n\n// walFileState holds an open WAL file handle and buffered writer for one host directory.\ntype walFileState struct {\n\tf     *os.File\n\tw     *bufio.Writer\n\tdirty bool\n\tsize  int64 // approximate bytes written (tracked from open + writes)\n}\n\n// walFlushInterval controls how often dirty WAL files are flushed to disk.\n// Decoupling flushes from message processing lets the consumer run at memory\n// speed, amortizing syscall overhead across many writes.\nconst walFlushInterval = 1 * time.Second\n\n// walShardIndex computes which shard a message belongs to based on cluster+node.\n// Uses FNV-1a hash for fast, well-distributed mapping.\nfunc walShardIndex(cluster, node string) int {\n\th := fnv.New32a()\n\th.Write([]byte(cluster))\n\th.Write([]byte{0})\n\th.Write([]byte(node))\n\treturn int(h.Sum32()) % walNumShards\n}\n\n// SendWALMessage routes a WAL message to the appropriate shard channel.\n// Returns false if the channel is full or shutdown is in progress.\nfunc SendWALMessage(msg *WALMessage) bool {\n\tif walShardChs == nil || walShuttingDown.Load() {\n\t\treturn false\n\t}\n\tshard := walShardIndex(msg.Cluster, msg.Node)\n\tselect {\n\tcase walShardChs[shard] <- msg:\n\t\treturn true\n\tdefault:\n\t\treturn false\n\t}\n}\n\n// WALStaging starts N sharded background goroutines that receive WALMessage items\n// and append binary WAL records to per-host current.wal files.\n// Each shard owns a subset of hosts (determined by hash of cluster+node),\n// parallelizing serialization and I/O while keeping per-host writes serial.\nfunc WALStaging(wg *sync.WaitGroup, ctx context.Context) {\n\tif Keys.Checkpoints.FileFormat == \"json\" {\n\t\treturn\n\t}\n\n\twalNumShards = max(Keys.NumWorkers, 1)\n\tchBufSize := max(65536/walNumShards, 1024)\n\n\twalShardChs = make([]chan *WALMessage, walNumShards)\n\twalShardRotateChs = make([]chan walRotateReq, walNumShards)\n\n\tfor i := range walNumShards {\n\t\twalShardChs[i] = make(chan *WALMessage, chBufSize)\n\t\twalShardRotateChs[i] = make(chan walRotateReq, 64)\n\t}\n\n\tfor i := range walNumShards {\n\t\tmsgCh := walShardChs[i]\n\t\trotateCh := walShardRotateChs[i]\n\n\t\twalStagingWg.Add(1)\n\t\twg.Go(func() {\n\t\t\tdefer walStagingWg.Done()\n\t\t\thostFiles := make(map[string]*walFileState)\n\n\t\t\tdefer func() {\n\t\t\t\tfor _, ws := range hostFiles {\n\t\t\t\t\tif ws.f != nil {\n\t\t\t\t\t\tws.w.Flush()\n\t\t\t\t\t\tws.f.Close()\n\t\t\t\t\t}\n\t\t\t\t}\n\t\t\t}()\n\n\t\t\tgetOrOpenWAL := func(hostDir string) *walFileState {\n\t\t\t\tws, ok := hostFiles[hostDir]\n\t\t\t\tif ok {\n\t\t\t\t\treturn ws","numLines":100,"startLine":100,"totalLines":979}},"sourceToolAssistantUUID":"dd405dc0-cf21-4c79-846a-ba0cad399945","userType":"external","entrypoint":"cli","cwd":"/Users/jan/prg/ClusterCockpit/cc-backend","sessionId":"88c65864-3f29-4b06-bbe1-7fab0c4a0142","version":"2.1.86","gitBranch":"hotfix","slug":"warm-enchanting-clarke"}
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+{"parentUuid":"3f2aa41a-602a-4d72-8f1e-c7852b215e07","isSidechain":false,"promptId":"9eaa6266-c81c-429f-b399-58d96fa3743c","type":"user","message":{"role":"user","content":[{"tool_use_id":"toolu_013N3hw2TianVcHKWwpDebEh","type":"tool_result","content":"200\t\t\t\t\t}\n201\t\n202\t\t\t\t\tif err := os.MkdirAll(hostDir, CheckpointDirPerms); err != nil {\n203\t\t\t\t\t\tcclog.Errorf(\"[METRICSTORE]> WAL: mkdir %s: %v\", hostDir, err)\n204\t\t\t\t\t\treturn nil\n205\t\t\t\t\t}\n206\t\n207\t\t\t\t\twalPath := path.Join(hostDir, \"current.wal\")\n208\t\t\t\t\tf, err := os.OpenFile(walPath, os.O_CREATE|os.O_APPEND|os.O_WRONLY, CheckpointFilePerms)\n209\t\t\t\t\tif err != nil {\n210\t\t\t\t\t\tcclog.Errorf(\"[METRICSTORE]> WAL: open %s: %v\", walPath, err)\n211\t\t\t\t\t\treturn nil\n212\t\t\t\t\t}\n213\t\n214\t\t\t\t\tw := bufio.NewWriter(f)\n215\t\n216\t\t\t\t\t// Write file header magic if file is new (empty).\n217\t\t\t\t\tinfo, err := f.Stat()\n218\t\t\t\t\tvar fileSize int64\n219\t\t\t\t\tif err == nil {\n220\t\t\t\t\t\tfileSize = info.Size()\n221\t\t\t\t\t}\n222\t\t\t\t\tif err == nil && fileSize == 0 {\n223\t\t\t\t\t\tvar hdr [4]byte\n224\t\t\t\t\t\tbinary.LittleEndian.PutUint32(hdr[:], walFileMagic)\n225\t\t\t\t\t\tif _, err := w.Write(hdr[:]); err != nil {\n226\t\t\t\t\t\t\tcclog.Errorf(\"[METRICSTORE]> WAL: write header %s: %v\", walPath, err)\n227\t\t\t\t\t\t\tf.Close()\n228\t\t\t\t\t\t\treturn nil\n229\t\t\t\t\t\t}\n230\t\t\t\t\t\tfileSize = 4\n231\t\t\t\t\t}\n232\t\n233\t\t\t\t\tws = &walFileState{f: f, w: w, size: fileSize}\n234\t\t\t\t\thostFiles[hostDir] = ws\n235\t\t\t\t\treturn ws\n236\t\t\t\t}\n237\t\n238\t\t\t\tprocessMsg := func(msg *WALMessage) {\n239\t\t\t\t\thostDir := path.Join(Keys.Checkpoints.RootDir, msg.Cluster, msg.Node)\n240\t\t\t\t\tws := getOrOpenWAL(hostDir)\n241\t\t\t\t\tif ws == nil {\n242\t\t\t\t\t\treturn\n243\t\t\t\t\t}\n244\t\n245\t\t\t\t\t// Enforce max WAL size: force-rotate before writing if limit is exceeded.\n246\t\t\t\t\t// The in-memory store still holds the data; only crash-recovery coverage is lost.\n247\t\t\t\t\tif maxSize := Keys.Checkpoints.MaxWALSize; maxSize > 0 && ws.size >= maxSize {\n248\t\t\t\t\t\tcclog.Warnf(\"[METRICSTORE]> WAL: force-rotating %s (size %d >= limit %d)\",\n249\t\t\t\t\t\t\thostDir, ws.size, maxSize)\n250\t\t\t\t\t\tws.w.Flush()\n251\t\t\t\t\t\tws.f.Close()\n252\t\t\t\t\t\twalPath := path.Join(hostDir, \"current.wal\")\n253\t\t\t\t\t\tif err := os.Remove(walPath); err != nil && !os.IsNotExist(err) {\n254\t\t\t\t\t\t\tcclog.Errorf(\"[METRICSTORE]> WAL: remove %s: %v\", walPath, err)\n255\t\t\t\t\t\t}\n256\t\t\t\t\t\tdelete(hostFiles, hostDir)\n257\t\t\t\t\t\tws = getOrOpenWAL(hostDir)\n258\t\t\t\t\t\tif ws == nil {\n259\t\t\t\t\t\t\treturn\n260\t\t\t\t\t\t}\n261\t\t\t\t\t}\n262\t\n263\t\t\t\t\tn, err := writeWALRecordDirect(ws.w, msg)\n264\t\t\t\t\tif err != nil {\n265\t\t\t\t\t\tcclog.Errorf(\"[METRICSTORE]> WAL: write record: %v\", err)\n266\t\t\t\t\t}\n267\t\t\t\t\tws.size += int64(n)\n268\t\t\t\t\tws.dirty = true\n269\t\t\t\t}\n270\t\n271\t\t\t\tprocessRotate := func(req walRotateReq) {\n272\t\t\t\t\tws, ok := hostFiles[req.hostDir]\n273\t\t\t\t\tif ok && ws.f != nil {\n274\t\t\t\t\t\tws.w.Flush()\n275\t\t\t\t\t\tws.f.Close()\n276\t\t\t\t\t\twalPath := path.Join(req.hostDir, \"current.wal\")\n277\t\t\t\t\t\tif err := os.Remove(walPath); err != nil && !os.IsNotExist(err) {\n278\t\t\t\t\t\t\tcclog.Errorf(\"[METRICSTORE]> WAL: remove %s: %v\", walPath, err)\n279\t\t\t\t\t\t}\n280\t\t\t\t\t\tdelete(hostFiles, req.hostDir)\n281\t\t\t\t\t}\n282\t\t\t\t\tclose(req.done)\n283\t\t\t\t}\n284\t\n285\t\t\t\tflushDirty := func() {\n286\t\t\t\t\tfor _, ws := range hostFiles {\n287\t\t\t\t\t\tif ws.dirty {\n288\t\t\t\t\t\t\tws.w.Flush()\n289\t\t\t\t\t\t\tws.dirty = false\n290\t\t\t\t\t\t}\n291\t\t\t\t\t}\n292\t\t\t\t}\n293\t\n294\t\t\t\tticker := time.NewTicker(walFlushInterval)\n295\t\t\t\tdefer ticker.Stop()\n296\t\n297\t\t\t\t// drainBatch processes up to 4096 pending messages without blocking.\n298\t\t\t\t// Returns false if the channel was closed.\n299\t\t\t\tdrainBatch := func() bool {"}]},"uuid":"e2197b8e-d5fc-4160-a3e0-c93fddd64003","timestamp":"2026-03-28T05:50:35.147Z","toolUseResult":{"type":"text","file":{"filePath":"/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go","content":"\t\t\t\t}\n\n\t\t\t\tif err := os.MkdirAll(hostDir, CheckpointDirPerms); err != nil {\n\t\t\t\t\tcclog.Errorf(\"[METRICSTORE]> WAL: mkdir %s: %v\", hostDir, err)\n\t\t\t\t\treturn nil\n\t\t\t\t}\n\n\t\t\t\twalPath := path.Join(hostDir, \"current.wal\")\n\t\t\t\tf, err := os.OpenFile(walPath, os.O_CREATE|os.O_APPEND|os.O_WRONLY, CheckpointFilePerms)\n\t\t\t\tif err != nil {\n\t\t\t\t\tcclog.Errorf(\"[METRICSTORE]> WAL: open %s: %v\", walPath, err)\n\t\t\t\t\treturn nil\n\t\t\t\t}\n\n\t\t\t\tw := bufio.NewWriter(f)\n\n\t\t\t\t// Write file header magic if file is new (empty).\n\t\t\t\tinfo, err := f.Stat()\n\t\t\t\tvar fileSize int64\n\t\t\t\tif err == nil {\n\t\t\t\t\tfileSize = info.Size()\n\t\t\t\t}\n\t\t\t\tif err == nil && fileSize == 0 {\n\t\t\t\t\tvar hdr [4]byte\n\t\t\t\t\tbinary.LittleEndian.PutUint32(hdr[:], walFileMagic)\n\t\t\t\t\tif _, err := w.Write(hdr[:]); err != nil {\n\t\t\t\t\t\tcclog.Errorf(\"[METRICSTORE]> WAL: write header %s: %v\", walPath, err)\n\t\t\t\t\t\tf.Close()\n\t\t\t\t\t\treturn nil\n\t\t\t\t\t}\n\t\t\t\t\tfileSize = 4\n\t\t\t\t}\n\n\t\t\t\tws = &walFileState{f: f, w: w, size: fileSize}\n\t\t\t\thostFiles[hostDir] = ws\n\t\t\t\treturn ws\n\t\t\t}\n\n\t\t\tprocessMsg := func(msg *WALMessage) {\n\t\t\t\thostDir := path.Join(Keys.Checkpoints.RootDir, msg.Cluster, msg.Node)\n\t\t\t\tws := getOrOpenWAL(hostDir)\n\t\t\t\tif ws == nil {\n\t\t\t\t\treturn\n\t\t\t\t}\n\n\t\t\t\t// Enforce max WAL size: force-rotate before writing if limit is exceeded.\n\t\t\t\t// The in-memory store still holds the data; only crash-recovery coverage is lost.\n\t\t\t\tif maxSize := Keys.Checkpoints.MaxWALSize; maxSize > 0 && ws.size >= maxSize {\n\t\t\t\t\tcclog.Warnf(\"[METRICSTORE]> WAL: force-rotating %s (size %d >= limit %d)\",\n\t\t\t\t\t\thostDir, ws.size, maxSize)\n\t\t\t\t\tws.w.Flush()\n\t\t\t\t\tws.f.Close()\n\t\t\t\t\twalPath := path.Join(hostDir, \"current.wal\")\n\t\t\t\t\tif err := os.Remove(walPath); err != nil && !os.IsNotExist(err) {\n\t\t\t\t\t\tcclog.Errorf(\"[METRICSTORE]> WAL: remove %s: %v\", walPath, err)\n\t\t\t\t\t}\n\t\t\t\t\tdelete(hostFiles, hostDir)\n\t\t\t\t\tws = getOrOpenWAL(hostDir)\n\t\t\t\t\tif ws == nil {\n\t\t\t\t\t\treturn\n\t\t\t\t\t}\n\t\t\t\t}\n\n\t\t\t\tn, err := writeWALRecordDirect(ws.w, msg)\n\t\t\t\tif err != nil {\n\t\t\t\t\tcclog.Errorf(\"[METRICSTORE]> WAL: write record: %v\", err)\n\t\t\t\t}\n\t\t\t\tws.size += int64(n)\n\t\t\t\tws.dirty = true\n\t\t\t}\n\n\t\t\tprocessRotate := func(req walRotateReq) {\n\t\t\t\tws, ok := hostFiles[req.hostDir]\n\t\t\t\tif ok && ws.f != nil {\n\t\t\t\t\tws.w.Flush()\n\t\t\t\t\tws.f.Close()\n\t\t\t\t\twalPath := path.Join(req.hostDir, \"current.wal\")\n\t\t\t\t\tif err := os.Remove(walPath); err != nil && !os.IsNotExist(err) {\n\t\t\t\t\t\tcclog.Errorf(\"[METRICSTORE]> WAL: remove %s: %v\", walPath, err)\n\t\t\t\t\t}\n\t\t\t\t\tdelete(hostFiles, req.hostDir)\n\t\t\t\t}\n\t\t\t\tclose(req.done)\n\t\t\t}\n\n\t\t\tflushDirty := func() {\n\t\t\t\tfor _, ws := range hostFiles {\n\t\t\t\t\tif ws.dirty {\n\t\t\t\t\t\tws.w.Flush()\n\t\t\t\t\t\tws.dirty = false\n\t\t\t\t\t}\n\t\t\t\t}\n\t\t\t}\n\n\t\t\tticker := time.NewTicker(walFlushInterval)\n\t\t\tdefer ticker.Stop()\n\n\t\t\t// drainBatch processes up to 4096 pending messages without blocking.\n\t\t\t// Returns false if the channel was closed.\n\t\t\tdrainBatch := func() bool {","numLines":100,"startLine":200,"totalLines":979}},"sourceToolAssistantUUID":"3f2aa41a-602a-4d72-8f1e-c7852b215e07","userType":"external","entrypoint":"cli","cwd":"/Users/jan/prg/ClusterCockpit/cc-backend","sessionId":"88c65864-3f29-4b06-bbe1-7fab0c4a0142","version":"2.1.86","gitBranch":"hotfix","slug":"warm-enchanting-clarke"}
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Each request is routed to the\n353\t// shard that owns the host directory.\n354\t//\n355\t// If shutdown is in progress (WAL staging goroutines may have exited),\n356\t// rotation is skipped to avoid deadlocking on abandoned channels.\n357\tfunc RotateWALFiles(hostDirs []string) {\n358\t\tif walShardRotateChs == nil || walShuttingDown.Load() {\n359\t\t\treturn\n360\t\t}\n361\t\tdones := make([]chan struct{}, 0, len(hostDirs))\n362\t\tfor _, dir := range hostDirs {\n363\t\t\tdone := make(chan struct{})\n364\t\t\tshard := walShardIndexFromDir(dir)\n365\t\t\tselect {\n366\t\t\tcase walShardRotateChs[shard] <- walRotateReq{hostDir: dir, done: done}:\n367\t\t\t\tdones = append(dones, done)\n368\t\t\tdefault:\n369\t\t\t\t// Channel full or goroutine not consuming — skip this host.\n370\t\t\t\tcclog.Warnf(\"[METRICSTORE]> WAL rotation skipped for %s (channel full)\", dir)\n371\t\t\t}\n372\t\t}\n373\t\tfor _, done := range dones {\n374\t\t\tselect {\n375\t\t\tcase <-done:\n376\t\t\tcase <-time.After(30 * time.Second):\n377\t\t\t\tcclog.Warn(\"[METRICSTORE]> WAL rotation timed out, continuing\")\n378\t\t\t\treturn\n379\t\t\t}\n380\t\t}\n381\t}\n382\t\n383\t// walShardIndexFromDir extracts cluster and node from a host directory path\n384\t// and returns the shard index. The path format is: rootDir/cluster/node\n385\tfunc walShardIndexFromDir(hostDir string) int {\n386\t\t// hostDir = .../cluster/node — extract last two path components\n387\t\tnode := path.Base(hostDir)\n388\t\tcluster := path.Base(path.Dir(hostDir))\n389\t\treturn walShardIndex(cluster, node)\n390\t}\n391\t\n392\t// RotateWALFiles sends rotation requests for the given host directories\n393\t// and blocks until all rotations complete.\n394\tfunc RotateWALFilesAfterShutdown(hostDirs []string) {\n395\t\tfor _, dir := range hostDirs {\n396\t\t\twalPath := path.Join(dir, \"current.wal\")\n397\t\t\tif err := os.Remove(walPath); err != nil && !os.IsNotExist(err) {\n398\t\t\t\tcclog.Errorf(\"[METRICSTORE]> WAL: remove %s: %v\", walPath, err)\n399\t\t\t}\n400\t\t}\n401\t}\n402\t\n403\t// writeWALRecordDirect encodes a WAL record into a contiguous buffer first,\n404\t// then writes it to the bufio.Writer in a single call. This prevents partial\n405\t// records in the write buffer if a write error occurs mid-record (e.g. disk full).\n406\t// Returns the number of bytes written and any error.\n407\tfunc writeWALRecordDirect(w *bufio.Writer, msg *WALMessage) (int, error) {\n408\t\t// Compute payload and total record size.\n409\t\tpayloadSize := 8 + 2 + len(msg.MetricName) + 1 + 4"}]},"uuid":"48bcfee3-44bb-4154-8cb5-cf8c5051f426","timestamp":"2026-03-28T05:50:38.000Z","toolUseResult":{"type":"text","file":{"filePath":"/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go","content":"\t\t\t\tfor range 4096 {\n\t\t\t\t\tselect {\n\t\t\t\t\tcase msg, ok := <-msgCh:\n\t\t\t\t\t\tif !ok {\n\t\t\t\t\t\t\tflushDirty()\n\t\t\t\t\t\t\treturn false\n\t\t\t\t\t\t}\n\t\t\t\t\t\tprocessMsg(msg)\n\t\t\t\t\tcase req := <-rotateCh:\n\t\t\t\t\t\tprocessRotate(req)\n\t\t\t\t\tdefault:\n\t\t\t\t\t\treturn true\n\t\t\t\t\t}\n\t\t\t\t}\n\t\t\t\treturn true\n\t\t\t}\n\n\t\t\tfor {\n\t\t\t\tselect {\n\t\t\t\tcase <-ctx.Done():\n\t\t\t\t\t// On shutdown, skip draining buffered messages — a full binary\n\t\t\t\t\t// checkpoint will be written from in-memory state, making\n\t\t\t\t\t// buffered WAL records redundant.\n\t\t\t\t\tflushDirty()\n\t\t\t\t\treturn\n\t\t\t\tcase msg, ok := <-msgCh:\n\t\t\t\t\tif !ok {\n\t\t\t\t\t\treturn\n\t\t\t\t\t}\n\t\t\t\t\tprocessMsg(msg)\n\t\t\t\t\tif !drainBatch() {\n\t\t\t\t\t\treturn\n\t\t\t\t\t}\n\t\t\t\t\t// No flush here — timer handles periodic flushing.\n\t\t\t\tcase <-ticker.C:\n\t\t\t\t\tflushDirty()\n\t\t\t\tcase req := <-rotateCh:\n\t\t\t\t\tprocessRotate(req)\n\t\t\t\t}\n\t\t\t}\n\t\t})\n\t}\n}\n\n// WaitForWALStagingDrain blocks until all WALStaging goroutines have exited.\n// Must be called after closing walShardChs to ensure all file handles are\n// flushed and closed before checkpoint writes begin.\nfunc WaitForWALStagingDrain() {\n\twalStagingWg.Wait()\n}\n\n// RotateWALFiles sends rotation requests for the given host directories\n// and blocks until all rotations complete. Each request is routed to the\n// shard that owns the host directory.\n//\n// If shutdown is in progress (WAL staging goroutines may have exited),\n// rotation is skipped to avoid deadlocking on abandoned channels.\nfunc RotateWALFiles(hostDirs []string) {\n\tif walShardRotateChs == nil || walShuttingDown.Load() {\n\t\treturn\n\t}\n\tdones := make([]chan struct{}, 0, len(hostDirs))\n\tfor _, dir := range hostDirs {\n\t\tdone := make(chan struct{})\n\t\tshard := walShardIndexFromDir(dir)\n\t\tselect {\n\t\tcase walShardRotateChs[shard] <- walRotateReq{hostDir: dir, done: done}:\n\t\t\tdones = append(dones, done)\n\t\tdefault:\n\t\t\t// Channel full or goroutine not consuming — skip this host.\n\t\t\tcclog.Warnf(\"[METRICSTORE]> WAL rotation skipped for %s (channel full)\", dir)\n\t\t}\n\t}\n\tfor _, done := range dones {\n\t\tselect {\n\t\tcase <-done:\n\t\tcase <-time.After(30 * time.Second):\n\t\t\tcclog.Warn(\"[METRICSTORE]> WAL rotation timed out, continuing\")\n\t\t\treturn\n\t\t}\n\t}\n}\n\n// walShardIndexFromDir extracts cluster and node from a host directory path\n// and returns the shard index. The path format is: rootDir/cluster/node\nfunc walShardIndexFromDir(hostDir string) int {\n\t// hostDir = .../cluster/node — extract last two path components\n\tnode := path.Base(hostDir)\n\tcluster := path.Base(path.Dir(hostDir))\n\treturn walShardIndex(cluster, node)\n}\n\n// RotateWALFiles sends rotation requests for the given host directories\n// and blocks until all rotations complete.\nfunc RotateWALFilesAfterShutdown(hostDirs []string) {\n\tfor _, dir := range hostDirs {\n\t\twalPath := path.Join(dir, \"current.wal\")\n\t\tif err := os.Remove(walPath); err != nil && !os.IsNotExist(err) {\n\t\t\tcclog.Errorf(\"[METRICSTORE]> WAL: remove %s: %v\", walPath, err)\n\t\t}\n\t}\n}\n\n// writeWALRecordDirect encodes a WAL record into a contiguous buffer first,\n// then writes it to the bufio.Writer in a single call. This prevents partial\n// records in the write buffer if a write error occurs mid-record (e.g. disk full).\n// Returns the number of bytes written and any error.\nfunc writeWALRecordDirect(w *bufio.Writer, msg *WALMessage) (int, error) {\n\t// Compute payload and total record size.\n\tpayloadSize := 8 + 2 + len(msg.MetricName) + 1 + 4","numLines":110,"startLine":300,"totalLines":979}},"sourceToolAssistantUUID":"8b165441-4f66-4ba8-ac6f-3435bb4f2d8e","userType":"external","entrypoint":"cli","cwd":"/Users/jan/prg/ClusterCockpit/cc-backend","sessionId":"88c65864-3f29-4b06-bbe1-7fab0c4a0142","version":"2.1.86","gitBranch":"hotfix","slug":"warm-enchanting-clarke"}
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+{"parentUuid":"181fa5c5-522f-48ee-bc98-9b0202ec5082","isSidechain":false,"promptId":"9eaa6266-c81c-429f-b399-58d96fa3743c","type":"user","message":{"role":"user","content":[{"tool_use_id":"toolu_01JgWxKAd1Ni1hpK1xHY8kQM","type":"tool_result","content":"/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-136-\t\t\t\t\t\tlastCheckpoint = now\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-137-\t\t\t\t\t\tlastCheckpointMu.Unlock()\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-138-\t\t\t\t\t\t// Rotate WAL files for successfully checkpointed hosts.\npkg/metricstore/checkpoint.go:139:\t\t\t\t\t\tRotateWALFiles(hostDirs)\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-140-\t\t\t\t\t}\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-141-\t\t\t\t} else {\npkg/metricstore/checkpoint.go-142-\t\t\t\t\tn, err := ms.ToCheckpoint(Keys.Checkpoints.RootDir, from.Unix(), now.Unix())\n--\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-354-//\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-355-// If shutdown is in progress (WAL staging goroutines may have exited),\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-356-// rotation is skipped to avoid deadlocking on abandoned channels.\npkg/metricstore/walCheckpoint.go:357:func RotateWALFiles(hostDirs []string) {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-358-\tif walShardRotateChs == nil || walShuttingDown.Load() {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-359-\t\treturn\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-360-\t}"}]},"uuid":"ce3cd07b-fa5c-4d09-8554-f2c52e066e22","timestamp":"2026-03-28T05:50:54.405Z","toolUseResult":{"mode":"content","numFiles":0,"filenames":[],"content":"/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-136-\t\t\t\t\t\tlastCheckpoint = now\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-137-\t\t\t\t\t\tlastCheckpointMu.Unlock()\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-138-\t\t\t\t\t\t// Rotate WAL files for successfully checkpointed hosts.\npkg/metricstore/checkpoint.go:139:\t\t\t\t\t\tRotateWALFiles(hostDirs)\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-140-\t\t\t\t\t}\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-141-\t\t\t\t} else {\npkg/metricstore/checkpoint.go-142-\t\t\t\t\tn, err := ms.ToCheckpoint(Keys.Checkpoints.RootDir, from.Unix(), now.Unix())\n--\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-354-//\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-355-// If shutdown is in progress (WAL staging goroutines may have exited),\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-356-// rotation is skipped to avoid deadlocking on abandoned channels.\npkg/metricstore/walCheckpoint.go:357:func RotateWALFiles(hostDirs []string) {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-358-\tif walShardRotateChs == nil || walShuttingDown.Load() {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-359-\t\treturn\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-360-\t}","numLines":15},"sourceToolAssistantUUID":"181fa5c5-522f-48ee-bc98-9b0202ec5082","userType":"external","entrypoint":"cli","cwd":"/Users/jan/prg/ClusterCockpit/cc-backend","sessionId":"88c65864-3f29-4b06-bbe1-7fab0c4a0142","version":"2.1.86","gitBranch":"hotfix","slug":"warm-enchanting-clarke"}
+{"parentUuid":"ce3cd07b-fa5c-4d09-8554-f2c52e066e22","isSidechain":false,"message":{"model":"claude-opus-4-6","id":"msg_01T6zjxgP39XYUhCMfW8ftXs","type":"message","role":"assistant","content":[{"type":"tool_use","id":"toolu_01XwbXtztENuuHNHP5eDECCp","name":"Grep","input":{"pattern":"hostDirs|ToBinaryCheckpoint","path":"/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go","output_mode":"content","-C":3},"caller":{"type":"direct"}}],"stop_reason":"tool_use","stop_sequence":null,"usage":{"input_tokens":1,"cache_creation_input_tokens":1199,"cache_read_input_tokens":29069,"output_tokens":140,"server_tool_use":{"web_search_requests":0,"web_fetch_requests":0},"service_tier":"standard","cache_creation":{"ephemeral_1h_input_tokens":1199,"ephemeral_5m_input_tokens":0},"inference_geo":"","iterations":[],"speed":"standard"}},"requestId":"req_011CZUxNv3XEf6gygw6pdqAD","type":"assistant","uuid":"8bf142f4-8e59-45eb-894a-4efeaa6aab36","timestamp":"2026-03-28T05:50:57.446Z","userType":"external","entrypoint":"cli","cwd":"/Users/jan/prg/ClusterCockpit/cc-backend","sessionId":"88c65864-3f29-4b06-bbe1-7fab0c4a0142","version":"2.1.86","gitBranch":"hotfix","slug":"warm-enchanting-clarke"}
+{"parentUuid":"8bf142f4-8e59-45eb-894a-4efeaa6aab36","isSidechain":false,"promptId":"9eaa6266-c81c-429f-b399-58d96fa3743c","type":"user","message":{"role":"user","content":[{"tool_use_id":"toolu_01XwbXtztENuuHNHP5eDECCp","type":"tool_result","content":"126-\t\t\t\tcclog.Infof(\"[METRICSTORE]> start checkpointing (starting at %s)...\", from.Format(time.RFC3339))\n127-\n128-\t\t\t\tif Keys.Checkpoints.FileFormat == \"wal\" {\n129:\t\t\t\t\tn, hostDirs, err := ms.ToCheckpointWAL(Keys.Checkpoints.RootDir, from.Unix(), now.Unix())\n130-\t\t\t\t\tif err != nil {\n131-\t\t\t\t\t\tcclog.Errorf(\"[METRICSTORE]> binary checkpointing failed: %s\", err.Error())\n132-\t\t\t\t\t}\n--\n136-\t\t\t\t\t\tlastCheckpoint = now\n137-\t\t\t\t\t\tlastCheckpointMu.Unlock()\n138-\t\t\t\t\t\t// Rotate WAL files for successfully checkpointed hosts.\n139:\t\t\t\t\t\tRotateWALFiles(hostDirs)\n140-\t\t\t\t\t}\n141-\t\t\t\t} else {\n142-\t\t\t\t\tn, err := ms.ToCheckpoint(Keys.Checkpoints.RootDir, from.Unix(), now.Unix())"}]},"uuid":"f1618640-04a1-40fb-9f6c-3ed63b3db6b9","timestamp":"2026-03-28T05:50:57.466Z","toolUseResult":{"mode":"content","numFiles":0,"filenames":[],"content":"126-\t\t\t\tcclog.Infof(\"[METRICSTORE]> start checkpointing (starting at %s)...\", from.Format(time.RFC3339))\n127-\n128-\t\t\t\tif Keys.Checkpoints.FileFormat == \"wal\" {\n129:\t\t\t\t\tn, hostDirs, err := ms.ToCheckpointWAL(Keys.Checkpoints.RootDir, from.Unix(), now.Unix())\n130-\t\t\t\t\tif err != nil {\n131-\t\t\t\t\t\tcclog.Errorf(\"[METRICSTORE]> binary checkpointing failed: %s\", err.Error())\n132-\t\t\t\t\t}\n--\n136-\t\t\t\t\t\tlastCheckpoint = now\n137-\t\t\t\t\t\tlastCheckpointMu.Unlock()\n138-\t\t\t\t\t\t// Rotate WAL files for successfully checkpointed hosts.\n139:\t\t\t\t\t\tRotateWALFiles(hostDirs)\n140-\t\t\t\t\t}\n141-\t\t\t\t} else {\n142-\t\t\t\t\tn, err := ms.ToCheckpoint(Keys.Checkpoints.RootDir, from.Unix(), now.Unix())","numLines":15},"sourceToolAssistantUUID":"8bf142f4-8e59-45eb-894a-4efeaa6aab36","userType":"external","entrypoint":"cli","cwd":"/Users/jan/prg/ClusterCockpit/cc-backend","sessionId":"88c65864-3f29-4b06-bbe1-7fab0c4a0142","version":"2.1.86","gitBranch":"hotfix","slug":"warm-enchanting-clarke"}
+{"parentUuid":"f1618640-04a1-40fb-9f6c-3ed63b3db6b9","isSidechain":false,"message":{"model":"claude-opus-4-6","id":"msg_01AQ2xzvTEUTQoDiWAaFD6vR","type":"message","role":"assistant","content":[{"type":"tool_use","id":"toolu_01TgUSWpXVWPw5gbaJxJYXzN","name":"Grep","input":{"pattern":"func.*ToCheckpointWAL","path":"/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore","output_mode":"content","-C":5},"caller":{"type":"direct"}}],"stop_reason":"tool_use","stop_sequence":null,"usage":{"input_tokens":1,"cache_creation_input_tokens":398,"cache_read_input_tokens":30268,"output_tokens":136,"server_tool_use":{"web_search_requests":0,"web_fetch_requests":0},"service_tier":"standard","cache_creation":{"ephemeral_1h_input_tokens":398,"ephemeral_5m_input_tokens":0},"inference_geo":"","iterations":[],"speed":"standard"}},"requestId":"req_011CZUxP92NdHZZmnyEcP2Hz","type":"assistant","uuid":"c990ca93-d4f9-4d71-8769-190a2df3c19a","timestamp":"2026-03-28T05:50:59.962Z","userType":"external","entrypoint":"cli","cwd":"/Users/jan/prg/ClusterCockpit/cc-backend","sessionId":"88c65864-3f29-4b06-bbe1-7fab0c4a0142","version":"2.1.86","gitBranch":"hotfix","slug":"warm-enchanting-clarke"}
+{"parentUuid":"c990ca93-d4f9-4d71-8769-190a2df3c19a","isSidechain":false,"promptId":"9eaa6266-c81c-429f-b399-58d96fa3743c","type":"user","message":{"role":"user","content":[{"tool_use_id":"toolu_01TgUSWpXVWPw5gbaJxJYXzN","type":"tool_result","content":"/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-650-}\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-651-\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-652-// ToCheckpointWAL writes binary snapshot files for all hosts in parallel.\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-653-// Returns the number of files written, the list of host directories that were\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-654-// successfully checkpointed (for WAL rotation), and any errors.\npkg/metricstore/walCheckpoint.go:655:func (m *MemoryStore) ToCheckpointWAL(dir string, from, to int64) (int, []string, error) {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-656-\t// Collect all cluster/host pairs.\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-657-\tm.root.lock.RLock()\npkg/metricstore/walCheckpoint.go-658-\ttotalHosts := 0\npkg/metricstore/walCheckpoint.go-659-\tfor _, l1 := range m.root.children {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-660-\t\tl1.lock.RLock()"}]},"uuid":"752c85d1-eb9c-43c4-b75a-aab0feb31922","timestamp":"2026-03-28T05:50:59.977Z","toolUseResult":{"mode":"content","numFiles":0,"filenames":[],"content":"/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-650-}\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-651-\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-652-// ToCheckpointWAL writes binary snapshot files for all hosts in parallel.\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-653-// Returns the number of files written, the list of host directories that were\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-654-// successfully checkpointed (for WAL rotation), and any errors.\npkg/metricstore/walCheckpoint.go:655:func (m *MemoryStore) ToCheckpointWAL(dir string, from, to int64) (int, []string, error) {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-656-\t// Collect all cluster/host pairs.\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-657-\tm.root.lock.RLock()\npkg/metricstore/walCheckpoint.go-658-\ttotalHosts := 0\npkg/metricstore/walCheckpoint.go-659-\tfor _, l1 := range m.root.children {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-660-\t\tl1.lock.RLock()","numLines":11},"sourceToolAssistantUUID":"c990ca93-d4f9-4d71-8769-190a2df3c19a","userType":"external","entrypoint":"cli","cwd":"/Users/jan/prg/ClusterCockpit/cc-backend","sessionId":"88c65864-3f29-4b06-bbe1-7fab0c4a0142","version":"2.1.86","gitBranch":"hotfix","slug":"warm-enchanting-clarke"}
+{"parentUuid":"752c85d1-eb9c-43c4-b75a-aab0feb31922","isSidechain":false,"message":{"model":"claude-opus-4-6","id":"msg_018xnNbC8iJkmGqJN2F5teus","type":"message","role":"assistant","content":[{"type":"text","text":"Now let me check how many hosts we're dealing with (the `NumWorkers` config that determines shard count)."}],"stop_reason":null,"stop_sequence":null,"usage":{"input_tokens":1,"cache_creation_input_tokens":701,"cache_read_input_tokens":30666,"cache_creation":{"ephemeral_5m_input_tokens":0,"ephemeral_1h_input_tokens":701},"output_tokens":1,"service_tier":"standard","inference_geo":"not_available"}},"requestId":"req_011CZUxPKqk3D5gAgwFV4je9","type":"assistant","uuid":"314a41a3-d74f-4975-9927-70cc4ef0aa91","timestamp":"2026-03-28T05:51:02.613Z","userType":"external","entrypoint":"cli","cwd":"/Users/jan/prg/ClusterCockpit/cc-backend","sessionId":"88c65864-3f29-4b06-bbe1-7fab0c4a0142","version":"2.1.86","gitBranch":"hotfix","slug":"warm-enchanting-clarke"}
+{"parentUuid":"314a41a3-d74f-4975-9927-70cc4ef0aa91","isSidechain":false,"message":{"model":"claude-opus-4-6","id":"msg_018xnNbC8iJkmGqJN2F5teus","type":"message","role":"assistant","content":[{"type":"tool_use","id":"toolu_019DyCewr83NRMGJ8ttgiu5u","name":"Grep","input":{"pattern":"NumWorkers","path":"/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore","output_mode":"content","-C":2},"caller":{"type":"direct"}}],"stop_reason":"tool_use","stop_sequence":null,"usage":{"input_tokens":1,"cache_creation_input_tokens":701,"cache_read_input_tokens":30666,"output_tokens":156,"server_tool_use":{"web_search_requests":0,"web_fetch_requests":0},"service_tier":"standard","cache_creation":{"ephemeral_1h_input_tokens":701,"ephemeral_5m_input_tokens":0},"inference_geo":"","iterations":[],"speed":"standard"}},"requestId":"req_011CZUxPKqk3D5gAgwFV4je9","type":"assistant","uuid":"5963218f-c1b5-4503-82c3-900f23673a25","timestamp":"2026-03-28T05:51:03.102Z","userType":"external","entrypoint":"cli","cwd":"/Users/jan/prg/ClusterCockpit/cc-backend","sessionId":"88c65864-3f29-4b06-bbe1-7fab0c4a0142","version":"2.1.86","gitBranch":"hotfix","slug":"warm-enchanting-clarke"}
+{"parentUuid":"5963218f-c1b5-4503-82c3-900f23673a25","isSidechain":false,"promptId":"9eaa6266-c81c-429f-b399-58d96fa3743c","type":"user","message":{"role":"user","content":[{"tool_use_id":"toolu_019DyCewr83NRMGJ8ttgiu5u","type":"tool_result","content":"/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/metricstore.go-134-\t}\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/metricstore.go-135-\npkg/metricstore/metricstore.go:136:\t// Set NumWorkers from config or use default\npkg/metricstore/metricstore.go:137:\tif Keys.NumWorkers <= 0 {\npkg/metricstore/metricstore.go:138:\t\tKeys.NumWorkers = min(runtime.NumCPU()/2+1, DefaultMaxWorkers)\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/metricstore.go-139-\t}\npkg/metricstore/metricstore.go:140:\tcclog.Debugf(\"[METRICSTORE]> Using %d workers for checkpoint/archive operations\\n\", Keys.NumWorkers)\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/metricstore.go-141-\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/metricstore.go-142-\t// Pass the config.MetricStoreKeys\n--\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/metricstore.go-186-\tif Keys.Subscriptions != nil {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/metricstore.go-187-\t\twg.Go(func() {\npkg/metricstore/metricstore.go:188:\t\t\tif err := ReceiveNats(ms, Keys.NumWorkers, ctx); err != nil {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/metricstore.go-189-\t\t\t\tcclog.Fatal(err)\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/metricstore.go-190-\t\t\t}\n--\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/archive.go-107-\tvar wg sync.WaitGroup\npkg/metricstore/archive.go-108-\tn, errs := int32(0), int32(0)\npkg/metricstore/archive.go:109:\twork := make(chan workItem, Keys.NumWorkers)\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/archive.go-110-\npkg/metricstore/archive.go:111:\twg.Add(Keys.NumWorkers)\npkg/metricstore/archive.go:112:\tfor worker := 0; worker < Keys.NumWorkers; worker++ {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/archive.go-113-\t\tgo func() {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/archive.go-114-\t\t\tdefer wg.Done()\n--\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/archive.go-206-\t\t}\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/archive.go-207-\npkg/metricstore/archive.go:208:\t\t// Small buffer provides back-pressure: at most NumWorkers+2 results in flight.\npkg/metricstore/archive.go-209-\t\tresults := make(chan hostResult, 2)\npkg/metricstore/archive.go-210-\t\twork := make(chan struct {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/archive.go-211-\t\t\tdir, host string\npkg/metricstore/archive.go:212:\t\t}, Keys.NumWorkers)\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/archive.go-213-\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/archive.go-214-\t\tvar wg sync.WaitGroup\npkg/metricstore/archive.go-215-\t\terrs := int32(0)\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/archive.go-216-\npkg/metricstore/archive.go:217:\t\twg.Add(Keys.NumWorkers)\npkg/metricstore/archive.go:218:\t\tfor w := 0; w < Keys.NumWorkers; w++ {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/archive.go-219-\t\t\tgo func() {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/archive.go-220-\t\t\t\tdefer wg.Done()\n--\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-183-//\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-184-// Metrics at root and cluster levels are skipped. One file per host is created.\npkg/metricstore/checkpoint.go:185:// Uses worker pool (Keys.NumWorkers) for parallel processing. Only locks one host\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-186-// at a time, allowing concurrent writes/reads to other hosts.\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-187-//\n--\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-221-\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-222-\tvar wg sync.WaitGroup\npkg/metricstore/checkpoint.go:223:\twg.Add(Keys.NumWorkers)\npkg/metricstore/checkpoint.go:224:\twork := make(chan workItem, Keys.NumWorkers*2)\npkg/metricstore/checkpoint.go:225:\tfor worker := 0; worker < Keys.NumWorkers; worker++ {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-226-\t\tgo func() {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-227-\t\t\tdefer wg.Done()\n--\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-396-func (m *MemoryStore) FromCheckpoint(dir string, from int64) (int, error) {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-397-\tvar wg sync.WaitGroup\npkg/metricstore/checkpoint.go:398:\twork := make(chan [2]string, Keys.NumWorkers*4)\npkg/metricstore/checkpoint.go-399-\tn, errs := int32(0), int32(0)\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-400-\npkg/metricstore/checkpoint.go:401:\twg.Add(Keys.NumWorkers)\npkg/metricstore/checkpoint.go:402:\tfor worker := 0; worker < Keys.NumWorkers; worker++ {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-403-\t\tgo func() {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-404-\t\t\tdefer wg.Done()\n--\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-165-\t}\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-166-\npkg/metricstore/walCheckpoint.go:167:\twalNumShards = max(Keys.NumWorkers, 1)\npkg/metricstore/walCheckpoint.go-168-\tchBufSize := max(65536/walNumShards, 1024)\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-169-\n--\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-685-\npkg/metricstore/walCheckpoint.go-686-\ttotalWork := len(levels)\npkg/metricstore/walCheckpoint.go:687:\tcclog.Infof(\"[METRICSTORE]> Starting binary checkpoint for %d hosts with %d workers\", totalWork, Keys.NumWorkers)\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-688-\npkg/metricstore/walCheckpoint.go-689-\tn, errs, completed := int32(0), int32(0), int32(0)\n--\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-692-\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-693-\tvar wg sync.WaitGroup\npkg/metricstore/walCheckpoint.go:694:\twg.Add(Keys.NumWorkers)\npkg/metricstore/walCheckpoint.go:695:\twork := make(chan workItem, Keys.NumWorkers*2)\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-696-\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-697-\t// Progress logging goroutine.\n--\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-711-\t}()\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-712-\npkg/metricstore/walCheckpoint.go:713:\tfor range Keys.NumWorkers {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-714-\t\tgo func() {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-715-\t\t\tdefer wg.Done()\n--\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/config.go-11-//\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/config.go-12-//\tMetricStoreConfig (Keys)\npkg/metricstore/config.go:13://\t├─ NumWorkers: Parallel checkpoint/archive workers\npkg/metricstore/config.go-14-/\t├─ RetentionInMemory: How long to keep data in RAM (also used as cleanup interval)\npkg/metricstore/config.go-15-/\t├─ MemoryCap: Memory limit in bytes (triggers forceFree)\n--\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/config.go-115-//\npkg/metricstore/config.go-116-/ Fields:\npkg/metricstore/config.go:117://   - NumWorkers:        Parallel workers for checkpoint/archive (0 = auto: min(NumCPU/2+1, 10))\npkg/metricstore/config.go-118-/   - RetentionInMemory: Duration string (e.g., \"48h\") for in-memory data retention\npkg/metricstore/config.go-119-/   - MemoryCap:         Max memory in GB for buffer data (0 = unlimited); triggers forceFree when exceeded\n--\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/config.go-125-\t// Number of concurrent workers for checkpoint and archive operations.\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/config.go-126-\t// If not set or 0, defaults to min(runtime.NumCPU()/2+1, 10)\npkg/metricstore/config.go:127:\tNumWorkers         int            `json:\"num-workers\"`\npkg/metricstore/config.go-128-\tRetentionInMemory  string         `json:\"retention-in-memory\"`\npkg/metricstore/config.go-129-\tCheckpointInterval string         `json:\"checkpoint-interval,omitempty\"`"}]},"uuid":"d129a339-af74-41fb-9081-b8c492b8abb9","timestamp":"2026-03-28T05:51:03.113Z","toolUseResult":{"mode":"content","numFiles":0,"filenames":[],"content":"/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/metricstore.go-134-\t}\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/metricstore.go-135-\npkg/metricstore/metricstore.go:136:\t// Set NumWorkers from config or use default\npkg/metricstore/metricstore.go:137:\tif Keys.NumWorkers <= 0 {\npkg/metricstore/metricstore.go:138:\t\tKeys.NumWorkers = min(runtime.NumCPU()/2+1, DefaultMaxWorkers)\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/metricstore.go-139-\t}\npkg/metricstore/metricstore.go:140:\tcclog.Debugf(\"[METRICSTORE]> Using %d workers for checkpoint/archive operations\\n\", Keys.NumWorkers)\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/metricstore.go-141-\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/metricstore.go-142-\t// Pass the config.MetricStoreKeys\n--\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/metricstore.go-186-\tif Keys.Subscriptions != nil {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/metricstore.go-187-\t\twg.Go(func() {\npkg/metricstore/metricstore.go:188:\t\t\tif err := ReceiveNats(ms, Keys.NumWorkers, ctx); err != nil {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/metricstore.go-189-\t\t\t\tcclog.Fatal(err)\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/metricstore.go-190-\t\t\t}\n--\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/archive.go-107-\tvar wg sync.WaitGroup\npkg/metricstore/archive.go-108-\tn, errs := int32(0), int32(0)\npkg/metricstore/archive.go:109:\twork := make(chan workItem, Keys.NumWorkers)\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/archive.go-110-\npkg/metricstore/archive.go:111:\twg.Add(Keys.NumWorkers)\npkg/metricstore/archive.go:112:\tfor worker := 0; worker < Keys.NumWorkers; worker++ {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/archive.go-113-\t\tgo func() {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/archive.go-114-\t\t\tdefer wg.Done()\n--\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/archive.go-206-\t\t}\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/archive.go-207-\npkg/metricstore/archive.go:208:\t\t// Small buffer provides back-pressure: at most NumWorkers+2 results in flight.\npkg/metricstore/archive.go-209-\t\tresults := make(chan hostResult, 2)\npkg/metricstore/archive.go-210-\t\twork := make(chan struct {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/archive.go-211-\t\t\tdir, host string\npkg/metricstore/archive.go:212:\t\t}, Keys.NumWorkers)\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/archive.go-213-\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/archive.go-214-\t\tvar wg sync.WaitGroup\npkg/metricstore/archive.go-215-\t\terrs := int32(0)\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/archive.go-216-\npkg/metricstore/archive.go:217:\t\twg.Add(Keys.NumWorkers)\npkg/metricstore/archive.go:218:\t\tfor w := 0; w < Keys.NumWorkers; w++ {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/archive.go-219-\t\t\tgo func() {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/archive.go-220-\t\t\t\tdefer wg.Done()\n--\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-183-//\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-184-// Metrics at root and cluster levels are skipped. One file per host is created.\npkg/metricstore/checkpoint.go:185:// Uses worker pool (Keys.NumWorkers) for parallel processing. Only locks one host\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-186-// at a time, allowing concurrent writes/reads to other hosts.\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-187-//\n--\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-221-\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-222-\tvar wg sync.WaitGroup\npkg/metricstore/checkpoint.go:223:\twg.Add(Keys.NumWorkers)\npkg/metricstore/checkpoint.go:224:\twork := make(chan workItem, Keys.NumWorkers*2)\npkg/metricstore/checkpoint.go:225:\tfor worker := 0; worker < Keys.NumWorkers; worker++ {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-226-\t\tgo func() {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-227-\t\t\tdefer wg.Done()\n--\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-396-func (m *MemoryStore) FromCheckpoint(dir string, from int64) (int, error) {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-397-\tvar wg sync.WaitGroup\npkg/metricstore/checkpoint.go:398:\twork := make(chan [2]string, Keys.NumWorkers*4)\npkg/metricstore/checkpoint.go-399-\tn, errs := int32(0), int32(0)\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-400-\npkg/metricstore/checkpoint.go:401:\twg.Add(Keys.NumWorkers)\npkg/metricstore/checkpoint.go:402:\tfor worker := 0; worker < Keys.NumWorkers; worker++ {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-403-\t\tgo func() {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/checkpoint.go-404-\t\t\tdefer wg.Done()\n--\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-165-\t}\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-166-\npkg/metricstore/walCheckpoint.go:167:\twalNumShards = max(Keys.NumWorkers, 1)\npkg/metricstore/walCheckpoint.go-168-\tchBufSize := max(65536/walNumShards, 1024)\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-169-\n--\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-685-\npkg/metricstore/walCheckpoint.go-686-\ttotalWork := len(levels)\npkg/metricstore/walCheckpoint.go:687:\tcclog.Infof(\"[METRICSTORE]> Starting binary checkpoint for %d hosts with %d workers\", totalWork, Keys.NumWorkers)\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-688-\npkg/metricstore/walCheckpoint.go-689-\tn, errs, completed := int32(0), int32(0), int32(0)\n--\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-692-\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-693-\tvar wg sync.WaitGroup\npkg/metricstore/walCheckpoint.go:694:\twg.Add(Keys.NumWorkers)\npkg/metricstore/walCheckpoint.go:695:\twork := make(chan workItem, Keys.NumWorkers*2)\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-696-\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-697-\t// Progress logging goroutine.\n--\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-711-\t}()\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-712-\npkg/metricstore/walCheckpoint.go:713:\tfor range Keys.NumWorkers {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-714-\t\tgo func() {\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go-715-\t\t\tdefer wg.Done()\n--\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/config.go-11-//\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/config.go-12-//\tMetricStoreConfig (Keys)\npkg/metricstore/config.go:13://\t├─ NumWorkers: Parallel checkpoint/archive workers\npkg/metricstore/config.go-14-/\t├─ RetentionInMemory: How long to keep data in RAM (also used as cleanup interval)\npkg/metricstore/config.go-15-/\t├─ MemoryCap: Memory limit in bytes (triggers forceFree)\n--\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/config.go-115-//\npkg/metricstore/config.go-116-/ Fields:\npkg/metricstore/config.go:117://   - NumWorkers:        Parallel workers for checkpoint/archive (0 = auto: min(NumCPU/2+1, 10))\npkg/metricstore/config.go-118-/   - RetentionInMemory: Duration string (e.g., \"48h\") for in-memory data retention\npkg/metricstore/config.go-119-/   - MemoryCap:         Max memory in GB for buffer data (0 = unlimited); triggers forceFree when exceeded\n--\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/config.go-125-\t// Number of concurrent workers for checkpoint and archive operations.\n/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/config.go-126-\t// If not set or 0, defaults to min(runtime.NumCPU()/2+1, 10)\npkg/metricstore/config.go:127:\tNumWorkers         int            `json:\"num-workers\"`\npkg/metricstore/config.go-128-\tRetentionInMemory  string         `json:\"retention-in-memory\"`\npkg/metricstore/config.go-129-\tCheckpointInterval string         `json:\"checkpoint-interval,omitempty\"`","numLines":107},"sourceToolAssistantUUID":"5963218f-c1b5-4503-82c3-900f23673a25","userType":"external","entrypoint":"cli","cwd":"/Users/jan/prg/ClusterCockpit/cc-backend","sessionId":"88c65864-3f29-4b06-bbe1-7fab0c4a0142","version":"2.1.86","gitBranch":"hotfix","slug":"warm-enchanting-clarke"}
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+{"parentUuid":"9dc97e6b-2533-42e0-89fd-1a7e66c425a4","isSidechain":false,"message":{"model":"claude-opus-4-6","id":"msg_01GSDQnXz2EGQVXCp6FA1YNx","type":"message","role":"assistant","content":[{"type":"tool_use","id":"toolu_01LwhtdmVec8eNDUfLaBxMGU","name":"Write","input":{"file_path":"/Users/jan/.claude/plans/warm-enchanting-clarke.md","content":"# Fix: WAL rotation \"channel full\" warnings for all nodes\n\n## Context\n\nAfter every checkpoint, **all** nodes log `WAL rotation skipped for ... (channel full)`. This means WAL files are never rotated (deleted after a successful binary snapshot), causing unbounded WAL file growth — effectively defeating the purpose of checkpointing.\n\n## Root Cause\n\nIn `pkg/metricstore/walCheckpoint.go`:\n\n1. **Rotation channels are small** (line 175): `walShardRotateChs[i] = make(chan walRotateReq, 64)` — buffer of 64 per shard.\n2. **Shards are few** (line 167): `walNumShards = max(Keys.NumWorkers, 1)` — typically 5-10 shards.\n3. **Hundreds of hosts per shard**: A large cluster like \"fritz\" has many hundreds of nodes. With ~10 shards, each shard handles ~100+ hosts.\n4. **Non-blocking send** (lines 365-371): `RotateWALFiles` uses `select { case ch <- req: ... default: skip }`. It sends all rotation requests in a tight loop without waiting.\n5. **Slow consumer**: The WAL staging goroutine processes one rotation at a time (flush + close + delete = I/O), interleaved with incoming metric messages.\n\nResult: The first 64 rotation requests per shard succeed (fill the buffer), then every subsequent host is skipped with the warning. Since the staging goroutine can't drain 64 I/O-bound rotations fast enough during the tight loop, nearly all nodes are skipped.\n\n## Fix\n\n**Change the non-blocking send to a blocking send with a timeout** in `RotateWALFiles` (line 365-371).\n\nThe checkpoint goroutine is a background task — it can afford to wait. This ensures all hosts get their WAL rotated.\n\n### File to modify\n\n`pkg/metricstore/walCheckpoint.go` — `RotateWALFiles` function (lines 357-381)\n\n### Change\n\nReplace the non-blocking `select` with a blocking send + timeout:\n\n```go\nfunc RotateWALFiles(hostDirs []string) {\n\tif walShardRotateChs == nil || walShuttingDown.Load() {\n\t\treturn\n\t}\n\tdones := make([]chan struct{}, 0, len(hostDirs))\n\tfor _, dir := range hostDirs {\n\t\tdone := make(chan struct{})\n\t\tshard := walShardIndexFromDir(dir)\n\t\tselect {\n\t\tcase walShardRotateChs[shard] <- walRotateReq{hostDir: dir, done: done}:\n\t\t\tdones = append(dones, done)\n\t\tcase <-time.After(30 * time.Second):\n\t\t\tcclog.Warnf(\"[METRICSTORE]> WAL rotation send timed out for %s\", dir)\n\t\t}\n\t}\n\tfor _, done := range dones {\n\t\tselect {\n\t\tcase <-done:\n\t\tcase <-time.After(30 * time.Second):\n\t\t\tcclog.Warn(\"[METRICSTORE]> WAL rotation timed out, continuing\")\n\t\t\treturn\n\t\t}\n\t}\n}\n```\n\nKey change: `default:` (non-blocking skip) becomes `case <-time.After(30 * time.Second):` (blocking with timeout). This allows the staging goroutine time to drain the channel.\n\n**Note**: Using `time.After` in a loop over potentially thousands of hosts creates a timer per iteration. Since this runs once per checkpoint interval (not a hot path), this is acceptable. If preferred, a single shared deadline can be used instead:\n\n```go\ndeadline := time.After(2 * time.Minute) // single deadline for all sends\nfor _, dir := range hostDirs {\n    done := make(chan struct{})\n    shard := walShardIndexFromDir(dir)\n    select {\n    case walShardRotateChs[shard] <- walRotateReq{hostDir: dir, done: done}:\n        dones = append(dones, done)\n    case <-deadline:\n        cclog.Warnf(\"[METRICSTORE]> WAL rotation send timed out after deadline, %d hosts remaining\", len(hostDirs)-len(dones))\n        goto waitDones\n    }\n}\n```\n\nI'd recommend the single-deadline approach for cleanliness.\n\n## Verification\n\n1. Build: `go build ./pkg/metricstore/...`\n2. Run tests: `go test ./pkg/metricstore/...`\n3. Deploy and observe: after checkpoint, no more \"channel full\" warnings; WAL files should be deleted for all hosts after each successful checkpoint.\n"},"caller":{"type":"direct"}}],"stop_reason":"tool_use","stop_sequence":null,"usage":{"input_tokens":1,"cache_creation_input_tokens":3433,"cache_read_input_tokens":31367,"output_tokens":1876,"server_tool_use":{"web_search_requests":0,"web_fetch_requests":0},"service_tier":"standard","cache_creation":{"ephemeral_1h_input_tokens":3433,"ephemeral_5m_input_tokens":0},"inference_geo":"","iterations":[],"speed":"standard"}},"requestId":"req_011CZUxPZHNv6DtbpiqjbUEC","type":"assistant","uuid":"958fcf4b-ba15-4f90-b22c-a81cd57411b2","timestamp":"2026-03-28T05:51:45.282Z","userType":"external","entrypoint":"cli","cwd":"/Users/jan/prg/ClusterCockpit/cc-backend","sessionId":"88c65864-3f29-4b06-bbe1-7fab0c4a0142","version":"2.1.86","gitBranch":"hotfix","slug":"warm-enchanting-clarke"}
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+{"parentUuid":"958fcf4b-ba15-4f90-b22c-a81cd57411b2","isSidechain":false,"promptId":"9eaa6266-c81c-429f-b399-58d96fa3743c","type":"user","message":{"role":"user","content":[{"tool_use_id":"toolu_01LwhtdmVec8eNDUfLaBxMGU","type":"tool_result","content":"File created successfully at: /Users/jan/.claude/plans/warm-enchanting-clarke.md"}]},"uuid":"b928a2ef-f93c-4144-99ad-bb5c8eccffd7","timestamp":"2026-03-28T05:51:45.299Z","toolUseResult":{"type":"create","filePath":"/Users/jan/.claude/plans/warm-enchanting-clarke.md","content":"# Fix: WAL rotation \"channel full\" warnings for all nodes\n\n## Context\n\nAfter every checkpoint, **all** nodes log `WAL rotation skipped for ... (channel full)`. This means WAL files are never rotated (deleted after a successful binary snapshot), causing unbounded WAL file growth — effectively defeating the purpose of checkpointing.\n\n## Root Cause\n\nIn `pkg/metricstore/walCheckpoint.go`:\n\n1. **Rotation channels are small** (line 175): `walShardRotateChs[i] = make(chan walRotateReq, 64)` — buffer of 64 per shard.\n2. **Shards are few** (line 167): `walNumShards = max(Keys.NumWorkers, 1)` — typically 5-10 shards.\n3. **Hundreds of hosts per shard**: A large cluster like \"fritz\" has many hundreds of nodes. With ~10 shards, each shard handles ~100+ hosts.\n4. **Non-blocking send** (lines 365-371): `RotateWALFiles` uses `select { case ch <- req: ... default: skip }`. It sends all rotation requests in a tight loop without waiting.\n5. **Slow consumer**: The WAL staging goroutine processes one rotation at a time (flush + close + delete = I/O), interleaved with incoming metric messages.\n\nResult: The first 64 rotation requests per shard succeed (fill the buffer), then every subsequent host is skipped with the warning. Since the staging goroutine can't drain 64 I/O-bound rotations fast enough during the tight loop, nearly all nodes are skipped.\n\n## Fix\n\n**Change the non-blocking send to a blocking send with a timeout** in `RotateWALFiles` (line 365-371).\n\nThe checkpoint goroutine is a background task — it can afford to wait. This ensures all hosts get their WAL rotated.\n\n### File to modify\n\n`pkg/metricstore/walCheckpoint.go` — `RotateWALFiles` function (lines 357-381)\n\n### Change\n\nReplace the non-blocking `select` with a blocking send + timeout:\n\n```go\nfunc RotateWALFiles(hostDirs []string) {\n\tif walShardRotateChs == nil || walShuttingDown.Load() {\n\t\treturn\n\t}\n\tdones := make([]chan struct{}, 0, len(hostDirs))\n\tfor _, dir := range hostDirs {\n\t\tdone := make(chan struct{})\n\t\tshard := walShardIndexFromDir(dir)\n\t\tselect {\n\t\tcase walShardRotateChs[shard] <- walRotateReq{hostDir: dir, done: done}:\n\t\t\tdones = append(dones, done)\n\t\tcase <-time.After(30 * time.Second):\n\t\t\tcclog.Warnf(\"[METRICSTORE]> WAL rotation send timed out for %s\", dir)\n\t\t}\n\t}\n\tfor _, done := range dones {\n\t\tselect {\n\t\tcase <-done:\n\t\tcase <-time.After(30 * time.Second):\n\t\t\tcclog.Warn(\"[METRICSTORE]> WAL rotation timed out, continuing\")\n\t\t\treturn\n\t\t}\n\t}\n}\n```\n\nKey change: `default:` (non-blocking skip) becomes `case <-time.After(30 * time.Second):` (blocking with timeout). This allows the staging goroutine time to drain the channel.\n\n**Note**: Using `time.After` in a loop over potentially thousands of hosts creates a timer per iteration. Since this runs once per checkpoint interval (not a hot path), this is acceptable. If preferred, a single shared deadline can be used instead:\n\n```go\ndeadline := time.After(2 * time.Minute) // single deadline for all sends\nfor _, dir := range hostDirs {\n    done := make(chan struct{})\n    shard := walShardIndexFromDir(dir)\n    select {\n    case walShardRotateChs[shard] <- walRotateReq{hostDir: dir, done: done}:\n        dones = append(dones, done)\n    case <-deadline:\n        cclog.Warnf(\"[METRICSTORE]> WAL rotation send timed out after deadline, %d hosts remaining\", len(hostDirs)-len(dones))\n        goto waitDones\n    }\n}\n```\n\nI'd recommend the single-deadline approach for cleanliness.\n\n## Verification\n\n1. Build: `go build ./pkg/metricstore/...`\n2. Run tests: `go test ./pkg/metricstore/...`\n3. Deploy and observe: after checkpoint, no more \"channel full\" warnings; WAL files should be deleted for all hosts after each successful checkpoint.\n","structuredPatch":[],"originalFile":null},"sourceToolAssistantUUID":"958fcf4b-ba15-4f90-b22c-a81cd57411b2","userType":"external","entrypoint":"cli","cwd":"/Users/jan/prg/ClusterCockpit/cc-backend","sessionId":"88c65864-3f29-4b06-bbe1-7fab0c4a0142","version":"2.1.86","gitBranch":"hotfix","slug":"warm-enchanting-clarke"}
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With thousands of nodes continuously sending metrics, the rotation channel may drain slowly because the goroutine alternates between large message batches and individual rotations.\n\nWith a blocking send + 2-minute deadline this should still work (each rotation is fast I/O — flush/close/delete), but if it proves tight, we could also process pending rotation requests inside `drainBatch()`. For now, the blocking-send fix alone should resolve the issue.\n\n## Verification","originalFile":"# Fix: WAL rotation \"channel full\" warnings for all nodes\n\n## Context\n\nAfter every checkpoint, **all** nodes log `WAL rotation skipped for ... (channel full)`. This means WAL files are never rotated (deleted after a successful binary snapshot), causing unbounded WAL file growth — effectively defeating the purpose of checkpointing.\n\n## Root Cause\n\nIn `pkg/metricstore/walCheckpoint.go`:\n\n1. **Rotation channels are small** (line 175): `walShardRotateChs[i] = make(chan walRotateReq, 64)` — buffer of 64 per shard.\n2. **Shards are few** (line 167): `walNumShards = max(Keys.NumWorkers, 1)` — typically 5-10 shards.\n3. **Hundreds of hosts per shard**: A large cluster like \"fritz\" has many hundreds of nodes. With ~10 shards, each shard handles ~100+ hosts.\n4. **Non-blocking send** (lines 365-371): `RotateWALFiles` uses `select { case ch <- req: ... default: skip }`. It sends all rotation requests in a tight loop without waiting.\n5. **Slow consumer**: The WAL staging goroutine processes one rotation at a time (flush + close + delete = I/O), interleaved with incoming metric messages.\n\nResult: The first 64 rotation requests per shard succeed (fill the buffer), then every subsequent host is skipped with the warning. Since the staging goroutine can't drain 64 I/O-bound rotations fast enough during the tight loop, nearly all nodes are skipped.\n\n## Fix\n\n**Change the non-blocking send to a blocking send with a timeout** in `RotateWALFiles` (line 365-371).\n\nThe checkpoint goroutine is a background task — it can afford to wait. This ensures all hosts get their WAL rotated.\n\n### File to modify\n\n`pkg/metricstore/walCheckpoint.go` — `RotateWALFiles` function (lines 357-381)\n\n### Change\n\nReplace the non-blocking `select` with a blocking send + timeout:\n\n```go\nfunc RotateWALFiles(hostDirs []string) {\n\tif walShardRotateChs == nil || walShuttingDown.Load() {\n\t\treturn\n\t}\n\tdones := make([]chan struct{}, 0, len(hostDirs))\n\tfor _, dir := range hostDirs {\n\t\tdone := make(chan struct{})\n\t\tshard := walShardIndexFromDir(dir)\n\t\tselect {\n\t\tcase walShardRotateChs[shard] <- walRotateReq{hostDir: dir, done: done}:\n\t\t\tdones = append(dones, done)\n\t\tcase <-time.After(30 * time.Second):\n\t\t\tcclog.Warnf(\"[METRICSTORE]> WAL rotation send timed out for %s\", dir)\n\t\t}\n\t}\n\tfor _, done := range dones {\n\t\tselect {\n\t\tcase <-done:\n\t\tcase <-time.After(30 * time.Second):\n\t\t\tcclog.Warn(\"[METRICSTORE]> WAL rotation timed out, continuing\")\n\t\t\treturn\n\t\t}\n\t}\n}\n```\n\nKey change: `default:` (non-blocking skip) becomes `case <-time.After(30 * time.Second):` (blocking with timeout). This allows the staging goroutine time to drain the channel.\n\n**Note**: Using `time.After` in a loop over potentially thousands of hosts creates a timer per iteration. Since this runs once per checkpoint interval (not a hot path), this is acceptable. If preferred, a single shared deadline can be used instead:\n\n```go\ndeadline := time.After(2 * time.Minute) // single deadline for all sends\nfor _, dir := range hostDirs {\n    done := make(chan struct{})\n    shard := walShardIndexFromDir(dir)\n    select {\n    case walShardRotateChs[shard] <- walRotateReq{hostDir: dir, done: done}:\n        dones = append(dones, done)\n    case <-deadline:\n        cclog.Warnf(\"[METRICSTORE]> WAL rotation send timed out after deadline, %d hosts remaining\", len(hostDirs)-len(dones))\n        goto waitDones\n    }\n}\n```\n\nI'd recommend the single-deadline approach for cleanliness.\n\n## Verification\n\n1. Build: `go build ./pkg/metricstore/...`\n2. Run tests: `go test ./pkg/metricstore/...`\n3. Deploy and observe: after checkpoint, no more \"channel full\" warnings; WAL files should be deleted for all hosts after each successful checkpoint.\n","structuredPatch":[{"oldStart":78,"oldLines":6,"newStart":78,"newLines":12,"lines":[" "," I'd recommend the single-deadline approach for cleanliness."," ","+### Additional consideration: rotation starvation under load","+","+The WAL staging goroutine's `drainBatch()` processes up to 4096 messages before yielding back to the main `select` (which can then pick a rotation request). With thousands of nodes continuously sending metrics, the rotation channel may drain slowly because the goroutine alternates between large message batches and individual rotations.","+","+With a blocking send + 2-minute deadline this should still work (each rotation is fast I/O — flush/close/delete), but if it proves tight, we could also process pending rotation requests inside `drainBatch()`. 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+{"parentUuid":"c2970bf1-27a3-478e-a8c8-33fada67a5e2","isSidechain":false,"message":{"model":"claude-opus-4-6","id":"msg_01WxF4Vp1u5wvLj2EKGm2uTV","type":"message","role":"assistant","content":[{"type":"text","text":"\n\nThe root cause is clear: `RotateWALFiles` uses a **non-blocking send** (`default:` case) on rotation channels buffered at only 64. With thousands of nodes and ~10 shards, the tight loop fills each shard's buffer instantly, and every remaining host is skipped. WAL files are never deleted.\n\nThe fix is simple: change the non-blocking send to a **blocking send with a timeout**, so the checkpoint goroutine waits for the staging goroutine to drain the channel instead of immediately giving up."}],"stop_reason":null,"stop_sequence":null,"usage":{"input_tokens":3,"cache_creation_input_tokens":738,"cache_read_input_tokens":37636,"cache_creation":{"ephemeral_5m_input_tokens":0,"ephemeral_1h_input_tokens":738},"output_tokens":2,"service_tier":"standard","inference_geo":"not_available"}},"requestId":"req_011CZUxURQzgK1V14iWcTLvf","type":"assistant","uuid":"d4013167-1587-449c-a79a-c9cbd120f3ea","timestamp":"2026-03-28T05:52:15.446Z","userType":"external","entrypoint":"cli","cwd":"/Users/jan/prg/ClusterCockpit/cc-backend","sessionId":"88c65864-3f29-4b06-bbe1-7fab0c4a0142","version":"2.1.86","gitBranch":"hotfix","slug":"warm-enchanting-clarke"}
+{"parentUuid":"d4013167-1587-449c-a79a-c9cbd120f3ea","isSidechain":false,"message":{"model":"claude-opus-4-6","id":"msg_01WxF4Vp1u5wvLj2EKGm2uTV","type":"message","role":"assistant","content":[{"type":"tool_use","id":"toolu_019oJpD2SSZYHL2k2bAeMXnC","name":"ExitPlanMode","input":{"allowedPrompts":[{"tool":"Bash","prompt":"build Go packages"},{"tool":"Bash","prompt":"run Go tests"}],"plan":"# Fix: WAL rotation \"channel full\" warnings for all nodes\n\n## Context\n\nAfter every checkpoint, **all** nodes log `WAL rotation skipped for ... (channel full)`. This means WAL files are never rotated (deleted after a successful binary snapshot), causing unbounded WAL file growth — effectively defeating the purpose of checkpointing.\n\n## Root Cause\n\nIn `pkg/metricstore/walCheckpoint.go`:\n\n1. **Rotation channels are small** (line 175): `walShardRotateChs[i] = make(chan walRotateReq, 64)` — buffer of 64 per shard.\n2. **Shards are few** (line 167): `walNumShards = max(Keys.NumWorkers, 1)` — typically 5-10 shards.\n3. **Hundreds of hosts per shard**: A large cluster like \"fritz\" has many hundreds of nodes. With ~10 shards, each shard handles ~100+ hosts.\n4. **Non-blocking send** (lines 365-371): `RotateWALFiles` uses `select { case ch <- req: ... default: skip }`. It sends all rotation requests in a tight loop without waiting.\n5. **Slow consumer**: The WAL staging goroutine processes one rotation at a time (flush + close + delete = I/O), interleaved with incoming metric messages.\n\nResult: The first 64 rotation requests per shard succeed (fill the buffer), then every subsequent host is skipped with the warning. Since the staging goroutine can't drain 64 I/O-bound rotations fast enough during the tight loop, nearly all nodes are skipped.\n\n## Fix\n\n**Change the non-blocking send to a blocking send with a timeout** in `RotateWALFiles` (line 365-371).\n\nThe checkpoint goroutine is a background task — it can afford to wait. This ensures all hosts get their WAL rotated.\n\n### File to modify\n\n`pkg/metricstore/walCheckpoint.go` — `RotateWALFiles` function (lines 357-381)\n\n### Change\n\nReplace the non-blocking `select` with a blocking send + timeout:\n\n```go\nfunc RotateWALFiles(hostDirs []string) {\n\tif walShardRotateChs == nil || walShuttingDown.Load() {\n\t\treturn\n\t}\n\tdones := make([]chan struct{}, 0, len(hostDirs))\n\tfor _, dir := range hostDirs {\n\t\tdone := make(chan struct{})\n\t\tshard := walShardIndexFromDir(dir)\n\t\tselect {\n\t\tcase walShardRotateChs[shard] <- walRotateReq{hostDir: dir, done: done}:\n\t\t\tdones = append(dones, done)\n\t\tcase <-time.After(30 * time.Second):\n\t\t\tcclog.Warnf(\"[METRICSTORE]> WAL rotation send timed out for %s\", dir)\n\t\t}\n\t}\n\tfor _, done := range dones {\n\t\tselect {\n\t\tcase <-done:\n\t\tcase <-time.After(30 * time.Second):\n\t\t\tcclog.Warn(\"[METRICSTORE]> WAL rotation timed out, continuing\")\n\t\t\treturn\n\t\t}\n\t}\n}\n```\n\nKey change: `default:` (non-blocking skip) becomes `case <-time.After(30 * time.Second):` (blocking with timeout). This allows the staging goroutine time to drain the channel.\n\n**Note**: Using `time.After` in a loop over potentially thousands of hosts creates a timer per iteration. Since this runs once per checkpoint interval (not a hot path), this is acceptable. If preferred, a single shared deadline can be used instead:\n\n```go\ndeadline := time.After(2 * time.Minute) // single deadline for all sends\nfor _, dir := range hostDirs {\n    done := make(chan struct{})\n    shard := walShardIndexFromDir(dir)\n    select {\n    case walShardRotateChs[shard] <- walRotateReq{hostDir: dir, done: done}:\n        dones = append(dones, done)\n    case <-deadline:\n        cclog.Warnf(\"[METRICSTORE]> WAL rotation send timed out after deadline, %d hosts remaining\", len(hostDirs)-len(dones))\n        goto waitDones\n    }\n}\n```\n\nI'd recommend the single-deadline approach for cleanliness.\n\n### Additional consideration: rotation starvation under load\n\nThe WAL staging goroutine's `drainBatch()` processes up to 4096 messages before yielding back to the main `select` (which can then pick a rotation request). With thousands of nodes continuously sending metrics, the rotation channel may drain slowly because the goroutine alternates between large message batches and individual rotations.\n\nWith a blocking send + 2-minute deadline this should still work (each rotation is fast I/O — flush/close/delete), but if it proves tight, we could also process pending rotation requests inside `drainBatch()`. For now, the blocking-send fix alone should resolve the issue.\n\n## Verification\n\n1. Build: `go build ./pkg/metricstore/...`\n2. Run tests: `go test ./pkg/metricstore/...`\n3. Deploy and observe: after checkpoint, no more \"channel full\" warnings; WAL files should be deleted for all hosts after each successful checkpoint.\n","planFilePath":"/Users/jan/.claude/plans/warm-enchanting-clarke.md"},"caller":{"type":"direct"}}],"stop_reason":"tool_use","stop_sequence":null,"usage":{"input_tokens":3,"cache_creation_input_tokens":738,"cache_read_input_tokens":37636,"output_tokens":213,"server_tool_use":{"web_search_requests":0,"web_fetch_requests":0},"service_tier":"standard","cache_creation":{"ephemeral_1h_input_tokens":738,"ephemeral_5m_input_tokens":0},"inference_geo":"","iterations":[],"speed":"standard"}},"requestId":"req_011CZUxURQzgK1V14iWcTLvf","type":"assistant","uuid":"e0691385-5568-4b68-83f7-64747a3fcd14","timestamp":"2026-03-28T05:52:15.862Z","userType":"external","entrypoint":"cli","cwd":"/Users/jan/prg/ClusterCockpit/cc-backend","sessionId":"88c65864-3f29-4b06-bbe1-7fab0c4a0142","version":"2.1.86","gitBranch":"hotfix","slug":"warm-enchanting-clarke"}
+{"parentUuid":"e0691385-5568-4b68-83f7-64747a3fcd14","isSidechain":false,"promptId":"9eaa6266-c81c-429f-b399-58d96fa3743c","type":"user","message":{"role":"user","content":[{"type":"tool_result","content":"User has approved your plan. You can now start coding. Start with updating your todo list if applicable\n\nYour plan has been saved to: /Users/jan/.claude/plans/warm-enchanting-clarke.md\nYou can refer back to it if needed during implementation.\n\n## Approved Plan:\n# Fix: WAL rotation \"channel full\" warnings for all nodes\n\n## Context\n\nAfter every checkpoint, **all** nodes log `WAL rotation skipped for ... (channel full)`. This means WAL files are never rotated (deleted after a successful binary snapshot), causing unbounded WAL file growth — effectively defeating the purpose of checkpointing.\n\n## Root Cause\n\nIn `pkg/metricstore/walCheckpoint.go`:\n\n1. **Rotation channels are small** (line 175): `walShardRotateChs[i] = make(chan walRotateReq, 64)` — buffer of 64 per shard.\n2. **Shards are few** (line 167): `walNumShards = max(Keys.NumWorkers, 1)` — typically 5-10 shards.\n3. **Hundreds of hosts per shard**: A large cluster like \"fritz\" has many hundreds of nodes. With ~10 shards, each shard handles ~100+ hosts.\n4. **Non-blocking send** (lines 365-371): `RotateWALFiles` uses `select { case ch <- req: ... default: skip }`. It sends all rotation requests in a tight loop without waiting.\n5. **Slow consumer**: The WAL staging goroutine processes one rotation at a time (flush + close + delete = I/O), interleaved with incoming metric messages.\n\nResult: The first 64 rotation requests per shard succeed (fill the buffer), then every subsequent host is skipped with the warning. Since the staging goroutine can't drain 64 I/O-bound rotations fast enough during the tight loop, nearly all nodes are skipped.\n\n## Fix\n\n**Change the non-blocking send to a blocking send with a timeout** in `RotateWALFiles` (line 365-371).\n\nThe checkpoint goroutine is a background task — it can afford to wait. This ensures all hosts get their WAL rotated.\n\n### File to modify\n\n`pkg/metricstore/walCheckpoint.go` — `RotateWALFiles` function (lines 357-381)\n\n### Change\n\nReplace the non-blocking `select` with a blocking send + timeout:\n\n```go\nfunc RotateWALFiles(hostDirs []string) {\n\tif walShardRotateChs == nil || walShuttingDown.Load() {\n\t\treturn\n\t}\n\tdones := make([]chan struct{}, 0, len(hostDirs))\n\tfor _, dir := range hostDirs {\n\t\tdone := make(chan struct{})\n\t\tshard := walShardIndexFromDir(dir)\n\t\tselect {\n\t\tcase walShardRotateChs[shard] <- walRotateReq{hostDir: dir, done: done}:\n\t\t\tdones = append(dones, done)\n\t\tcase <-time.After(30 * time.Second):\n\t\t\tcclog.Warnf(\"[METRICSTORE]> WAL rotation send timed out for %s\", dir)\n\t\t}\n\t}\n\tfor _, done := range dones {\n\t\tselect {\n\t\tcase <-done:\n\t\tcase <-time.After(30 * time.Second):\n\t\t\tcclog.Warn(\"[METRICSTORE]> WAL rotation timed out, continuing\")\n\t\t\treturn\n\t\t}\n\t}\n}\n```\n\nKey change: `default:` (non-blocking skip) becomes `case <-time.After(30 * time.Second):` (blocking with timeout). This allows the staging goroutine time to drain the channel.\n\n**Note**: Using `time.After` in a loop over potentially thousands of hosts creates a timer per iteration. Since this runs once per checkpoint interval (not a hot path), this is acceptable. If preferred, a single shared deadline can be used instead:\n\n```go\ndeadline := time.After(2 * time.Minute) // single deadline for all sends\nfor _, dir := range hostDirs {\n    done := make(chan struct{})\n    shard := walShardIndexFromDir(dir)\n    select {\n    case walShardRotateChs[shard] <- walRotateReq{hostDir: dir, done: done}:\n        dones = append(dones, done)\n    case <-deadline:\n        cclog.Warnf(\"[METRICSTORE]> WAL rotation send timed out after deadline, %d hosts remaining\", len(hostDirs)-len(dones))\n        goto waitDones\n    }\n}\n```\n\nI'd recommend the single-deadline approach for cleanliness.\n\n### Additional consideration: rotation starvation under load\n\nThe WAL staging goroutine's `drainBatch()` processes up to 4096 messages before yielding back to the main `select` (which can then pick a rotation request). With thousands of nodes continuously sending metrics, the rotation channel may drain slowly because the goroutine alternates between large message batches and individual rotations.\n\nWith a blocking send + 2-minute deadline this should still work (each rotation is fast I/O — flush/close/delete), but if it proves tight, we could also process pending rotation requests inside `drainBatch()`. For now, the blocking-send fix alone should resolve the issue.\n\n## Verification\n\n1. Build: `go build ./pkg/metricstore/...`\n2. Run tests: `go test ./pkg/metricstore/...`\n3. Deploy and observe: after checkpoint, no more \"channel full\" warnings; WAL files should be deleted for all hosts after each successful checkpoint.\n","tool_use_id":"toolu_019oJpD2SSZYHL2k2bAeMXnC"}]},"uuid":"af5eb298-22ee-460d-ac78-91cfd90b1dc6","timestamp":"2026-03-28T05:54:19.334Z","toolUseResult":{"plan":"# Fix: WAL rotation \"channel full\" warnings for all nodes\n\n## Context\n\nAfter every checkpoint, **all** nodes log `WAL rotation skipped for ... (channel full)`. This means WAL files are never rotated (deleted after a successful binary snapshot), causing unbounded WAL file growth — effectively defeating the purpose of checkpointing.\n\n## Root Cause\n\nIn `pkg/metricstore/walCheckpoint.go`:\n\n1. **Rotation channels are small** (line 175): `walShardRotateChs[i] = make(chan walRotateReq, 64)` — buffer of 64 per shard.\n2. **Shards are few** (line 167): `walNumShards = max(Keys.NumWorkers, 1)` — typically 5-10 shards.\n3. **Hundreds of hosts per shard**: A large cluster like \"fritz\" has many hundreds of nodes. With ~10 shards, each shard handles ~100+ hosts.\n4. **Non-blocking send** (lines 365-371): `RotateWALFiles` uses `select { case ch <- req: ... default: skip }`. It sends all rotation requests in a tight loop without waiting.\n5. **Slow consumer**: The WAL staging goroutine processes one rotation at a time (flush + close + delete = I/O), interleaved with incoming metric messages.\n\nResult: The first 64 rotation requests per shard succeed (fill the buffer), then every subsequent host is skipped with the warning. Since the staging goroutine can't drain 64 I/O-bound rotations fast enough during the tight loop, nearly all nodes are skipped.\n\n## Fix\n\n**Change the non-blocking send to a blocking send with a timeout** in `RotateWALFiles` (line 365-371).\n\nThe checkpoint goroutine is a background task — it can afford to wait. This ensures all hosts get their WAL rotated.\n\n### File to modify\n\n`pkg/metricstore/walCheckpoint.go` — `RotateWALFiles` function (lines 357-381)\n\n### Change\n\nReplace the non-blocking `select` with a blocking send + timeout:\n\n```go\nfunc RotateWALFiles(hostDirs []string) {\n\tif walShardRotateChs == nil || walShuttingDown.Load() {\n\t\treturn\n\t}\n\tdones := make([]chan struct{}, 0, len(hostDirs))\n\tfor _, dir := range hostDirs {\n\t\tdone := make(chan struct{})\n\t\tshard := walShardIndexFromDir(dir)\n\t\tselect {\n\t\tcase walShardRotateChs[shard] <- walRotateReq{hostDir: dir, done: done}:\n\t\t\tdones = append(dones, done)\n\t\tcase <-time.After(30 * time.Second):\n\t\t\tcclog.Warnf(\"[METRICSTORE]> WAL rotation send timed out for %s\", dir)\n\t\t}\n\t}\n\tfor _, done := range dones {\n\t\tselect {\n\t\tcase <-done:\n\t\tcase <-time.After(30 * time.Second):\n\t\t\tcclog.Warn(\"[METRICSTORE]> WAL rotation timed out, continuing\")\n\t\t\treturn\n\t\t}\n\t}\n}\n```\n\nKey change: `default:` (non-blocking skip) becomes `case <-time.After(30 * time.Second):` (blocking with timeout). This allows the staging goroutine time to drain the channel.\n\n**Note**: Using `time.After` in a loop over potentially thousands of hosts creates a timer per iteration. Since this runs once per checkpoint interval (not a hot path), this is acceptable. If preferred, a single shared deadline can be used instead:\n\n```go\ndeadline := time.After(2 * time.Minute) // single deadline for all sends\nfor _, dir := range hostDirs {\n    done := make(chan struct{})\n    shard := walShardIndexFromDir(dir)\n    select {\n    case walShardRotateChs[shard] <- walRotateReq{hostDir: dir, done: done}:\n        dones = append(dones, done)\n    case <-deadline:\n        cclog.Warnf(\"[METRICSTORE]> WAL rotation send timed out after deadline, %d hosts remaining\", len(hostDirs)-len(dones))\n        goto waitDones\n    }\n}\n```\n\nI'd recommend the single-deadline approach for cleanliness.\n\n### Additional consideration: rotation starvation under load\n\nThe WAL staging goroutine's `drainBatch()` processes up to 4096 messages before yielding back to the main `select` (which can then pick a rotation request). With thousands of nodes continuously sending metrics, the rotation channel may drain slowly because the goroutine alternates between large message batches and individual rotations.\n\nWith a blocking send + 2-minute deadline this should still work (each rotation is fast I/O — flush/close/delete), but if it proves tight, we could also process pending rotation requests inside `drainBatch()`. For now, the blocking-send fix alone should resolve the issue.\n\n## Verification\n\n1. Build: `go build ./pkg/metricstore/...`\n2. Run tests: `go test ./pkg/metricstore/...`\n3. Deploy and observe: after checkpoint, no more \"channel full\" warnings; WAL files should be deleted for all hosts after each successful checkpoint.\n","isAgent":false,"filePath":"/Users/jan/.claude/plans/warm-enchanting-clarke.md"},"sourceToolAssistantUUID":"e0691385-5568-4b68-83f7-64747a3fcd14","userType":"external","entrypoint":"cli","cwd":"/Users/jan/prg/ClusterCockpit/cc-backend","sessionId":"88c65864-3f29-4b06-bbe1-7fab0c4a0142","version":"2.1.86","gitBranch":"hotfix","slug":"warm-enchanting-clarke"}
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+{"parentUuid":"7e469f12-0e0c-4250-8784-6f4e81a1795c","isSidechain":false,"promptId":"9eaa6266-c81c-429f-b399-58d96fa3743c","type":"user","message":{"role":"user","content":[{"tool_use_id":"toolu_01TvzNev4xR9wCq5XUmdCyqo","type":"tool_result","content":"The file /Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go has been updated successfully."}]},"uuid":"0e833fd6-04da-4543-b754-50e6179bf163","timestamp":"2026-03-28T05:54:28.394Z","toolUseResult":{"filePath":"/Users/jan/prg/ClusterCockpit/cc-backend/pkg/metricstore/walCheckpoint.go","oldString":"func RotateWALFiles(hostDirs []string) {\n\tif walShardRotateChs == nil || walShuttingDown.Load() {\n\t\treturn\n\t}\n\tdones := make([]chan struct{}, 0, len(hostDirs))\n\tfor _, dir := range hostDirs {\n\t\tdone := make(chan struct{})\n\t\tshard := walShardIndexFromDir(dir)\n\t\tselect {\n\t\tcase walShardRotateChs[shard] <- walRotateReq{hostDir: dir, done: done}:\n\t\t\tdones = append(dones, done)\n\t\tdefault:\n\t\t\t// Channel full or goroutine not consuming — skip this host.\n\t\t\tcclog.Warnf(\"[METRICSTORE]> WAL rotation skipped for %s (channel full)\", dir)\n\t\t}\n\t}\n\tfor _, done := range dones {\n\t\tselect {\n\t\tcase <-done:\n\t\tcase <-time.After(30 * time.Second):\n\t\t\tcclog.Warn(\"[METRICSTORE]> WAL rotation timed out, continuing\")\n\t\t\treturn\n\t\t}\n\t}\n}","newString":"func RotateWALFiles(hostDirs []string) {\n\tif walShardRotateChs == nil || walShuttingDown.Load() {\n\t\treturn\n\t}\n\tdeadline := time.After(2 * time.Minute)\n\tdones := make([]chan struct{}, 0, len(hostDirs))\n\tfor _, dir := range hostDirs {\n\t\tdone := make(chan struct{})\n\t\tshard := walShardIndexFromDir(dir)\n\t\tselect {\n\t\tcase walShardRotateChs[shard] <- walRotateReq{hostDir: dir, done: done}:\n\t\t\tdones = append(dones, done)\n\t\tcase <-deadline:\n\t\t\tcclog.Warnf(\"[METRICSTORE]> WAL rotation send timed out, %d of %d hosts remaining\",\n\t\t\t\tlen(hostDirs)-len(dones), len(hostDirs))\n\t\t\tgoto waitDones\n\t\t}\n\t}\nwaitDones:\n\tfor _, done := range dones {\n\t\tselect {\n\t\tcase <-done:\n\t\tcase <-time.After(30 * time.Second):\n\t\t\tcclog.Warn(\"[METRICSTORE]> WAL rotation completion timed out, continuing\")\n\t\t\treturn\n\t\t}\n\t}\n}","originalFile":"// Copyright (C) NHR@FAU, University Erlangen-Nuremberg.\n// All rights reserved. This file is part of cc-backend.\n// Use of this source code is governed by a MIT-style\n// license that can be found in the LICENSE file.\n\n// Package metricstore provides walCheckpoint.go: WAL-based checkpoint implementation.\n//\n// This replaces the Avro shadow tree with an append-only Write-Ahead Log (WAL)\n// per host, eliminating the extra memory overhead of the AvroStore and providing\n// truly continuous (per-write) crash safety.\n//\n// # Architecture\n//\n//\tMetric write (DecodeLine)\n//\t      │\n//\t      ├─► WriteToLevel()    → main MemoryStore (unchanged)\n//\t      │\n//\t      └─► WALMessages channel\n//\t               │\n//\t               ▼\n//\t        WALStaging goroutine\n//\t               │\n//\t               ▼\n//\t        checkpoints/cluster/host/current.wal  (append-only, binary)\n//\n//\tPeriodic checkpoint (Checkpointing goroutine):\n//\t  1. Write <timestamp>.bin snapshot (column-oriented, from main tree)\n//\t  2. Signal WALStaging to truncate current.wal per host\n//\n//\tOn restart (FromCheckpoint):\n//\t  1. Load most recent <timestamp>.bin snapshot\n//\t  2. Replay current.wal (overwrite-safe: buffer.write handles duplicate timestamps)\n//\n// # WAL Record Format\n//\n//\t[4B magic 0xCC1DA7A1][4B payload_len][payload][4B CRC32]\n//\n//\tpayload:\n//\t  [8B timestamp int64]\n//\t  [2B metric_name_len uint16][N metric name bytes]\n//\t  [1B selector_count uint8]\n//\t  per selector: [1B selector_len uint8][M selector bytes]\n//\t  [4B value float32 bits]\n//\n// # Binary Snapshot Format\n//\n//\t[4B magic 0xCC5B0001][8B from int64][8B to int64]\n//\tLevel tree (recursive):\n//\t  [4B num_metrics uint32]\n//\t  per metric:\n//\t    [2B name_len uint16][N name bytes]\n//\t    [8B frequency int64][8B start int64]\n//\t    [4B num_values uint32][num_values × 4B float32]\n//\t  [4B num_children uint32]\n//\t  per child: [2B name_len uint16][N name bytes] + Level (recursive)\npackage metricstore\n\nimport (\n\t\"bufio\"\n\t\"context\"\n\t\"encoding/binary\"\n\t\"fmt\"\n\t\"hash/crc32\"\n\t\"hash/fnv\"\n\t\"io\"\n\t\"math\"\n\t\"os\"\n\t\"path\"\n\t\"strings\"\n\t\"sync\"\n\t\"sync/atomic\"\n\t\"time\"\n\n\tcclog \"github.com/ClusterCockpit/cc-lib/v2/ccLogger\"\n\t\"github.com/ClusterCockpit/cc-lib/v2/schema\"\n)\n\n// Magic numbers for binary formats.\nconst (\n\twalFileMagic   = uint32(0xCC1DA701) // WAL file header magic\n\twalRecordMagic = uint32(0xCC1DA7A1) // WAL record magic\n\tsnapFileMagic  = uint32(0xCC5B0001) // Binary snapshot magic\n)\n\n// walShardChs holds per-shard channels for WAL messages.\n// Initialized by WALStaging; nil when WAL is not active.\nvar walShardChs []chan *WALMessage\n\n// walShardRotateChs holds per-shard channels for WAL rotation requests.\nvar walShardRotateChs []chan walRotateReq\n\n// walNumShards stores the number of shards (set during WALStaging init).\nvar walNumShards int\n\n// walStagingWg tracks WALStaging goroutine exits for shutdown synchronization.\nvar walStagingWg sync.WaitGroup\n\n// walShuttingDown is set before closing shard channels to prevent\n// SendWALMessage from sending on a closed channel (which panics in Go).\nvar walShuttingDown atomic.Bool\n\n// WALMessage represents a single metric write to be appended to the WAL.\n// Cluster and Node are NOT stored in the WAL record (inferred from file path).\ntype WALMessage struct {\n\tMetricName string\n\tCluster    string\n\tNode       string\n\tSelector   []string\n\tValue      schema.Float\n\tTimestamp  int64\n}\n\n// walRotateReq requests WAL file rotation for a specific host directory.\n// The done channel is closed by the WAL goroutine when rotation is complete.\ntype walRotateReq struct {\n\thostDir string\n\tdone    chan struct{}\n}\n\n// walFileState holds an open WAL file handle and buffered writer for one host directory.\ntype walFileState struct {\n\tf     *os.File\n\tw     *bufio.Writer\n\tdirty bool\n\tsize  int64 // approximate bytes written (tracked from open + writes)\n}\n\n// walFlushInterval controls how often dirty WAL files are flushed to disk.\n// Decoupling flushes from message processing lets the consumer run at memory\n// speed, amortizing syscall overhead across many writes.\nconst walFlushInterval = 1 * time.Second\n\n// walShardIndex computes which shard a message belongs to based on cluster+node.\n// Uses FNV-1a hash for fast, well-distributed mapping.\nfunc walShardIndex(cluster, node string) int {\n\th := fnv.New32a()\n\th.Write([]byte(cluster))\n\th.Write([]byte{0})\n\th.Write([]byte(node))\n\treturn int(h.Sum32()) % walNumShards\n}\n\n// SendWALMessage routes a WAL message to the appropriate shard channel.\n// Returns false if the channel is full or shutdown is in progress.\nfunc SendWALMessage(msg *WALMessage) bool {\n\tif walShardChs == nil || walShuttingDown.Load() {\n\t\treturn false\n\t}\n\tshard := walShardIndex(msg.Cluster, msg.Node)\n\tselect {\n\tcase walShardChs[shard] <- msg:\n\t\treturn true\n\tdefault:\n\t\treturn false\n\t}\n}\n\n// WALStaging starts N sharded background goroutines that receive WALMessage items\n// and append binary WAL records to per-host current.wal files.\n// Each shard owns a subset of hosts (determined by hash of cluster+node),\n// parallelizing serialization and I/O while keeping per-host writes serial.\nfunc WALStaging(wg *sync.WaitGroup, ctx context.Context) {\n\tif Keys.Checkpoints.FileFormat == \"json\" {\n\t\treturn\n\t}\n\n\twalNumShards = max(Keys.NumWorkers, 1)\n\tchBufSize := max(65536/walNumShards, 1024)\n\n\twalShardChs = make([]chan *WALMessage, walNumShards)\n\twalShardRotateChs = make([]chan walRotateReq, walNumShards)\n\n\tfor i := range walNumShards {\n\t\twalShardChs[i] = make(chan *WALMessage, chBufSize)\n\t\twalShardRotateChs[i] = make(chan walRotateReq, 64)\n\t}\n\n\tfor i := range walNumShards {\n\t\tmsgCh := walShardChs[i]\n\t\trotateCh := walShardRotateChs[i]\n\n\t\twalStagingWg.Add(1)\n\t\twg.Go(func() {\n\t\t\tdefer walStagingWg.Done()\n\t\t\thostFiles := make(map[string]*walFileState)\n\n\t\t\tdefer func() {\n\t\t\t\tfor _, ws := range hostFiles {\n\t\t\t\t\tif ws.f != nil {\n\t\t\t\t\t\tws.w.Flush()\n\t\t\t\t\t\tws.f.Close()\n\t\t\t\t\t}\n\t\t\t\t}\n\t\t\t}()\n\n\t\t\tgetOrOpenWAL := func(hostDir string) *walFileState {\n\t\t\t\tws, ok := hostFiles[hostDir]\n\t\t\t\tif ok {\n\t\t\t\t\treturn ws\n\t\t\t\t}\n\n\t\t\t\tif err := os.MkdirAll(hostDir, CheckpointDirPerms); err != nil {\n\t\t\t\t\tcclog.Errorf(\"[METRICSTORE]> WAL: mkdir %s: %v\", hostDir, err)\n\t\t\t\t\treturn nil\n\t\t\t\t}\n\n\t\t\t\twalPath := path.Join(hostDir, \"current.wal\")\n\t\t\t\tf, err := os.OpenFile(walPath, os.O_CREATE|os.O_APPEND|os.O_WRONLY, CheckpointFilePerms)\n\t\t\t\tif err != nil {\n\t\t\t\t\tcclog.Errorf(\"[METRICSTORE]> WAL: open %s: %v\", walPath, err)\n\t\t\t\t\treturn nil\n\t\t\t\t}\n\n\t\t\t\tw := bufio.NewWriter(f)\n\n\t\t\t\t// Write file header magic if file is new (empty).\n\t\t\t\tinfo, err := f.Stat()\n\t\t\t\tvar fileSize int64\n\t\t\t\tif err == nil {\n\t\t\t\t\tfileSize = info.Size()\n\t\t\t\t}\n\t\t\t\tif err == nil && fileSize == 0 {\n\t\t\t\t\tvar hdr [4]byte\n\t\t\t\t\tbinary.LittleEndian.PutUint32(hdr[:], walFileMagic)\n\t\t\t\t\tif _, err := w.Write(hdr[:]); err != nil {\n\t\t\t\t\t\tcclog.Errorf(\"[METRICSTORE]> WAL: write header %s: %v\", walPath, err)\n\t\t\t\t\t\tf.Close()\n\t\t\t\t\t\treturn nil\n\t\t\t\t\t}\n\t\t\t\t\tfileSize = 4\n\t\t\t\t}\n\n\t\t\t\tws = &walFileState{f: f, w: w, size: fileSize}\n\t\t\t\thostFiles[hostDir] = ws\n\t\t\t\treturn ws\n\t\t\t}\n\n\t\t\tprocessMsg := func(msg *WALMessage) {\n\t\t\t\thostDir := path.Join(Keys.Checkpoints.RootDir, msg.Cluster, msg.Node)\n\t\t\t\tws := getOrOpenWAL(hostDir)\n\t\t\t\tif ws == nil {\n\t\t\t\t\treturn\n\t\t\t\t}\n\n\t\t\t\t// Enforce max WAL size: force-rotate before writing if limit is exceeded.\n\t\t\t\t// The in-memory store still holds the data; only crash-recovery coverage is lost.\n\t\t\t\tif maxSize := Keys.Checkpoints.MaxWALSize; maxSize > 0 && ws.size >= maxSize {\n\t\t\t\t\tcclog.Warnf(\"[METRICSTORE]> WAL: force-rotating %s (size %d >= limit %d)\",\n\t\t\t\t\t\thostDir, ws.size, maxSize)\n\t\t\t\t\tws.w.Flush()\n\t\t\t\t\tws.f.Close()\n\t\t\t\t\twalPath := path.Join(hostDir, \"current.wal\")\n\t\t\t\t\tif err := os.Remove(walPath); err != nil && !os.IsNotExist(err) {\n\t\t\t\t\t\tcclog.Errorf(\"[METRICSTORE]> WAL: remove %s: %v\", walPath, err)\n\t\t\t\t\t}\n\t\t\t\t\tdelete(hostFiles, hostDir)\n\t\t\t\t\tws = getOrOpenWAL(hostDir)\n\t\t\t\t\tif ws == nil {\n\t\t\t\t\t\treturn\n\t\t\t\t\t}\n\t\t\t\t}\n\n\t\t\t\tn, err := writeWALRecordDirect(ws.w, msg)\n\t\t\t\tif err != nil {\n\t\t\t\t\tcclog.Errorf(\"[METRICSTORE]> WAL: write record: %v\", err)\n\t\t\t\t}\n\t\t\t\tws.size += int64(n)\n\t\t\t\tws.dirty = true\n\t\t\t}\n\n\t\t\tprocessRotate := func(req walRotateReq) {\n\t\t\t\tws, ok := hostFiles[req.hostDir]\n\t\t\t\tif ok && ws.f != nil {\n\t\t\t\t\tws.w.Flush()\n\t\t\t\t\tws.f.Close()\n\t\t\t\t\twalPath := path.Join(req.hostDir, \"current.wal\")\n\t\t\t\t\tif err := os.Remove(walPath); err != nil && !os.IsNotExist(err) {\n\t\t\t\t\t\tcclog.Errorf(\"[METRICSTORE]> WAL: remove %s: %v\", walPath, err)\n\t\t\t\t\t}\n\t\t\t\t\tdelete(hostFiles, req.hostDir)\n\t\t\t\t}\n\t\t\t\tclose(req.done)\n\t\t\t}\n\n\t\t\tflushDirty := func() {\n\t\t\t\tfor _, ws := range hostFiles {\n\t\t\t\t\tif ws.dirty {\n\t\t\t\t\t\tws.w.Flush()\n\t\t\t\t\t\tws.dirty = false\n\t\t\t\t\t}\n\t\t\t\t}\n\t\t\t}\n\n\t\t\tticker := time.NewTicker(walFlushInterval)\n\t\t\tdefer ticker.Stop()\n\n\t\t\t// drainBatch processes up to 4096 pending messages without blocking.\n\t\t\t// Returns false if the channel was closed.\n\t\t\tdrainBatch := func() bool {\n\t\t\t\tfor range 4096 {\n\t\t\t\t\tselect {\n\t\t\t\t\tcase msg, ok := <-msgCh:\n\t\t\t\t\t\tif !ok {\n\t\t\t\t\t\t\tflushDirty()\n\t\t\t\t\t\t\treturn false\n\t\t\t\t\t\t}\n\t\t\t\t\t\tprocessMsg(msg)\n\t\t\t\t\tcase req := <-rotateCh:\n\t\t\t\t\t\tprocessRotate(req)\n\t\t\t\t\tdefault:\n\t\t\t\t\t\treturn true\n\t\t\t\t\t}\n\t\t\t\t}\n\t\t\t\treturn true\n\t\t\t}\n\n\t\t\tfor {\n\t\t\t\tselect {\n\t\t\t\tcase <-ctx.Done():\n\t\t\t\t\t// On shutdown, skip draining buffered messages — a full binary\n\t\t\t\t\t// checkpoint will be written from in-memory state, making\n\t\t\t\t\t// buffered WAL records redundant.\n\t\t\t\t\tflushDirty()\n\t\t\t\t\treturn\n\t\t\t\tcase msg, ok := <-msgCh:\n\t\t\t\t\tif !ok {\n\t\t\t\t\t\treturn\n\t\t\t\t\t}\n\t\t\t\t\tprocessMsg(msg)\n\t\t\t\t\tif !drainBatch() {\n\t\t\t\t\t\treturn\n\t\t\t\t\t}\n\t\t\t\t\t// No flush here — timer handles periodic flushing.\n\t\t\t\tcase <-ticker.C:\n\t\t\t\t\tflushDirty()\n\t\t\t\tcase req := <-rotateCh:\n\t\t\t\t\tprocessRotate(req)\n\t\t\t\t}\n\t\t\t}\n\t\t})\n\t}\n}\n\n// WaitForWALStagingDrain blocks until all WALStaging goroutines have exited.\n// Must be called after closing walShardChs to ensure all file handles are\n// flushed and closed before checkpoint writes begin.\nfunc WaitForWALStagingDrain() {\n\twalStagingWg.Wait()\n}\n\n// RotateWALFiles sends rotation requests for the given host directories\n// and blocks until all rotations complete. Each request is routed to the\n// shard that owns the host directory.\n//\n// If shutdown is in progress (WAL staging goroutines may have exited),\n// rotation is skipped to avoid deadlocking on abandoned channels.\nfunc RotateWALFiles(hostDirs []string) {\n\tif walShardRotateChs == nil || walShuttingDown.Load() {\n\t\treturn\n\t}\n\tdones := make([]chan struct{}, 0, len(hostDirs))\n\tfor _, dir := range hostDirs {\n\t\tdone := make(chan struct{})\n\t\tshard := walShardIndexFromDir(dir)\n\t\tselect {\n\t\tcase walShardRotateChs[shard] <- walRotateReq{hostDir: dir, done: done}:\n\t\t\tdones = append(dones, done)\n\t\tdefault:\n\t\t\t// Channel full or goroutine not consuming — skip this host.\n\t\t\tcclog.Warnf(\"[METRICSTORE]> WAL rotation skipped for %s (channel full)\", dir)\n\t\t}\n\t}\n\tfor _, done := range dones {\n\t\tselect {\n\t\tcase <-done:\n\t\tcase <-time.After(30 * time.Second):\n\t\t\tcclog.Warn(\"[METRICSTORE]> WAL rotation timed out, continuing\")\n\t\t\treturn\n\t\t}\n\t}\n}\n\n// walShardIndexFromDir extracts cluster and node from a host directory path\n// and returns the shard index. The path format is: rootDir/cluster/node\nfunc walShardIndexFromDir(hostDir string) int {\n\t// hostDir = .../cluster/node — extract last two path components\n\tnode := path.Base(hostDir)\n\tcluster := path.Base(path.Dir(hostDir))\n\treturn walShardIndex(cluster, node)\n}\n\n// RotateWALFiles sends rotation requests for the given host directories\n// and blocks until all rotations complete.\nfunc RotateWALFilesAfterShutdown(hostDirs []string) {\n\tfor _, dir := range hostDirs {\n\t\twalPath := path.Join(dir, \"current.wal\")\n\t\tif err := os.Remove(walPath); err != nil && !os.IsNotExist(err) {\n\t\t\tcclog.Errorf(\"[METRICSTORE]> WAL: remove %s: %v\", walPath, err)\n\t\t}\n\t}\n}\n\n// writeWALRecordDirect encodes a WAL record into a contiguous buffer first,\n// then writes it to the bufio.Writer in a single call. This prevents partial\n// records in the write buffer if a write error occurs mid-record (e.g. disk full).\n// Returns the number of bytes written and any error.\nfunc writeWALRecordDirect(w *bufio.Writer, msg *WALMessage) (int, error) {\n\t// Compute payload and total record size.\n\tpayloadSize := 8 + 2 + len(msg.MetricName) + 1 + 4\n\tfor _, s := range msg.Selector {\n\t\tpayloadSize += 1 + len(s)\n\t}\n\t// Total: 8 (header) + payload + 4 (CRC).\n\ttotalSize := 8 + payloadSize + 4\n\n\t// Use stack buffer for typical small records, heap-allocate only for large ones.\n\tvar stackBuf [256]byte\n\tvar buf []byte\n\tif totalSize <= len(stackBuf) {\n\t\tbuf = stackBuf[:totalSize]\n\t} else {\n\t\tbuf = make([]byte, totalSize)\n\t}\n\n\t// Header: magic + payload length.\n\tbinary.LittleEndian.PutUint32(buf[0:4], walRecordMagic)\n\tbinary.LittleEndian.PutUint32(buf[4:8], uint32(payloadSize))\n\n\t// Payload starts at offset 8.\n\tp := 8\n\n\t// Timestamp (8 bytes).\n\tbinary.LittleEndian.PutUint64(buf[p:p+8], uint64(msg.Timestamp))\n\tp += 8\n\n\t// Metric name length (2 bytes) + metric name.\n\tbinary.LittleEndian.PutUint16(buf[p:p+2], uint16(len(msg.MetricName)))\n\tp += 2\n\tp += copy(buf[p:], msg.MetricName)\n\n\t// Selector count (1 byte).\n\tbuf[p] = byte(len(msg.Selector))\n\tp++\n\n\t// Selectors (1-byte length + bytes each).\n\tfor _, sel := range msg.Selector {\n\t\tbuf[p] = byte(len(sel))\n\t\tp++\n\t\tp += copy(buf[p:], sel)\n\t}\n\n\t// Value (4 bytes, float32 bits).\n\tbinary.LittleEndian.PutUint32(buf[p:p+4], math.Float32bits(float32(msg.Value)))\n\tp += 4\n\n\t// CRC32 over payload (bytes 8..8+payloadSize).\n\tcrc := crc32.ChecksumIEEE(buf[8 : 8+payloadSize])\n\tbinary.LittleEndian.PutUint32(buf[p:p+4], crc)\n\n\t// Single atomic write to the buffered writer.\n\tn, err := w.Write(buf)\n\treturn n, err\n}\n\n// readWALRecord reads one WAL record from the reader.\n// Returns (nil, nil) on clean EOF. Returns error on data corruption.\n// A CRC mismatch indicates a truncated trailing record (expected on crash).\nfunc readWALRecord(r io.Reader) (*WALMessage, error) {\n\tvar magic uint32\n\tif err := binary.Read(r, binary.LittleEndian, &magic); err != nil {\n\t\tif err == io.EOF {\n\t\t\treturn nil, nil // Clean EOF\n\t\t}\n\t\treturn nil, fmt.Errorf(\"read record magic: %w\", err)\n\t}\n\n\tif magic != walRecordMagic {\n\t\treturn nil, fmt.Errorf(\"invalid record magic 0x%08X (expected 0x%08X)\", magic, walRecordMagic)\n\t}\n\n\tvar payloadLen uint32\n\tif err := binary.Read(r, binary.LittleEndian, &payloadLen); err != nil {\n\t\treturn nil, fmt.Errorf(\"read payload length: %w\", err)\n\t}\n\n\tif payloadLen > 1<<20 { // 1 MB sanity limit\n\t\treturn nil, fmt.Errorf(\"record payload too large: %d bytes\", payloadLen)\n\t}\n\n\tpayload := make([]byte, payloadLen)\n\tif _, err := io.ReadFull(r, payload); err != nil {\n\t\treturn nil, fmt.Errorf(\"read payload: %w\", err)\n\t}\n\n\tvar storedCRC uint32\n\tif err := binary.Read(r, binary.LittleEndian, &storedCRC); err != nil {\n\t\treturn nil, fmt.Errorf(\"read CRC: %w\", err)\n\t}\n\n\tif crc32.ChecksumIEEE(payload) != storedCRC {\n\t\treturn nil, fmt.Errorf(\"CRC mismatch (truncated write or corruption)\")\n\t}\n\n\treturn parseWALPayload(payload)\n}\n\n// parseWALPayload decodes a binary payload into a WALMessage.\nfunc parseWALPayload(payload []byte) (*WALMessage, error) {\n\tif len(payload) < 8+2+1+4 {\n\t\treturn nil, fmt.Errorf(\"payload too short: %d bytes\", len(payload))\n\t}\n\n\toffset := 0\n\n\t// Timestamp (8 bytes)\n\tts := int64(binary.LittleEndian.Uint64(payload[offset : offset+8]))\n\toffset += 8\n\n\t// Metric name (2-byte length + bytes)\n\tif offset+2 > len(payload) {\n\t\treturn nil, fmt.Errorf(\"metric name length overflows payload\")\n\t}\n\tmLen := int(binary.LittleEndian.Uint16(payload[offset : offset+2]))\n\toffset += 2\n\n\tif offset+mLen > len(payload) {\n\t\treturn nil, fmt.Errorf(\"metric name overflows payload\")\n\t}\n\tmetricName := string(payload[offset : offset+mLen])\n\toffset += mLen\n\n\t// Selector count (1 byte)\n\tif offset >= len(payload) {\n\t\treturn nil, fmt.Errorf(\"selector count overflows payload\")\n\t}\n\tselCount := int(payload[offset])\n\toffset++\n\n\tselectors := make([]string, selCount)\n\tfor i := range selCount {\n\t\tif offset >= len(payload) {\n\t\t\treturn nil, fmt.Errorf(\"selector[%d] length overflows payload\", i)\n\t\t}\n\t\tsLen := int(payload[offset])\n\t\toffset++\n\n\t\tif offset+sLen > len(payload) {\n\t\t\treturn nil, fmt.Errorf(\"selector[%d] data overflows payload\", i)\n\t\t}\n\t\tselectors[i] = string(payload[offset : offset+sLen])\n\t\toffset += sLen\n\t}\n\n\t// Value (4 bytes, float32 bits)\n\tif offset+4 > len(payload) {\n\t\treturn nil, fmt.Errorf(\"value overflows payload\")\n\t}\n\tbits := binary.LittleEndian.Uint32(payload[offset : offset+4])\n\tvalue := schema.Float(math.Float32frombits(bits))\n\n\treturn &WALMessage{\n\t\tMetricName: metricName,\n\t\tTimestamp:  ts,\n\t\tSelector:   selectors,\n\t\tValue:      value,\n\t}, nil\n}\n\n// loadWALFile reads a WAL file and replays all valid records into the Level tree.\n// l is the host-level node. Corrupt or partial trailing records are silently skipped\n// (expected on crash). Records older than 'from' are skipped.\nfunc (l *Level) loadWALFile(m *MemoryStore, f *os.File, from int64) error {\n\tbr := bufio.NewReader(f)\n\n\t// Verify file header magic.\n\tvar fileMagic uint32\n\tif err := binary.Read(br, binary.LittleEndian, &fileMagic); err != nil {\n\t\tif err == io.EOF {\n\t\t\treturn nil // Empty file, no data\n\t\t}\n\t\treturn fmt.Errorf(\"[METRICSTORE]> WAL: read file header: %w\", err)\n\t}\n\n\tif fileMagic != walFileMagic {\n\t\treturn fmt.Errorf(\"[METRICSTORE]> WAL: invalid file magic 0x%08X (expected 0x%08X)\", fileMagic, walFileMagic)\n\t}\n\n\t// Cache level lookups to avoid repeated tree traversal.\n\tlvlCache := make(map[string]*Level)\n\n\tfor {\n\t\tmsg, err := readWALRecord(br)\n\t\tif err != nil {\n\t\t\t// Truncated trailing record is expected after a crash; stop replaying.\n\t\t\tcclog.Debugf(\"[METRICSTORE]> WAL: stopping replay at corrupted/partial record: %v\", err)\n\t\t\tbreak\n\t\t}\n\t\tif msg == nil {\n\t\t\tbreak // Clean EOF\n\t\t}\n\n\t\tif msg.Timestamp < from {\n\t\t\tcontinue // Older than retention window\n\t\t}\n\n\t\tminfo, ok := m.Metrics[msg.MetricName]\n\t\tif !ok {\n\t\t\tcontinue // Unknown metric (config may have changed)\n\t\t}\n\n\t\t// Cache key is the null-separated selector path.\n\t\tcacheKey := joinSelector(msg.Selector)\n\t\tlvl, ok := lvlCache[cacheKey]\n\t\tif !ok {\n\t\t\tlvl = l.findLevelOrCreate(msg.Selector, len(m.Metrics))\n\t\t\tlvlCache[cacheKey] = lvl\n\t\t}\n\n\t\t// Write directly to the buffer, same as WriteToLevel but without the\n\t\t// global level lookup (we already have the right level).\n\t\tlvl.lock.Lock()\n\t\tb := lvl.metrics[minfo.offset]\n\t\tif b == nil {\n\t\t\tb = newBuffer(msg.Timestamp, minfo.Frequency)\n\t\t\tlvl.metrics[minfo.offset] = b\n\t\t}\n\t\tnb, writeErr := b.write(msg.Timestamp, msg.Value)\n\t\tif writeErr == nil && b != nb {\n\t\t\tlvl.metrics[minfo.offset] = nb\n\t\t}\n\t\t// Ignore write errors for timestamps before buffer start (can happen when\n\t\t// replaying WAL entries that predate a loaded snapshot's start time).\n\t\tlvl.lock.Unlock()\n\t}\n\n\treturn nil\n}\n\n// joinSelector builds a cache key from a selector slice using null bytes as separators.\nfunc joinSelector(sel []string) string {\n\tif len(sel) == 0 {\n\t\treturn \"\"\n\t}\n\tvar result strings.Builder\n\tresult.WriteString(sel[0])\n\tfor i := 1; i < len(sel); i++ {\n\t\tresult.WriteString(\"\\x00\" + sel[i])\n\t}\n\treturn result.String()\n}\n\n// ToCheckpointWAL writes binary snapshot files for all hosts in parallel.\n// Returns the number of files written, the list of host directories that were\n// successfully checkpointed (for WAL rotation), and any errors.\nfunc (m *MemoryStore) ToCheckpointWAL(dir string, from, to int64) (int, []string, error) {\n\t// Collect all cluster/host pairs.\n\tm.root.lock.RLock()\n\ttotalHosts := 0\n\tfor _, l1 := range m.root.children {\n\t\tl1.lock.RLock()\n\t\ttotalHosts += len(l1.children)\n\t\tl1.lock.RUnlock()\n\t}\n\tm.root.lock.RUnlock()\n\n\tlevels := make([]*Level, 0, totalHosts)\n\tselectors := make([][]string, 0, totalHosts)\n\n\tm.root.lock.RLock()\n\tfor sel1, l1 := range m.root.children {\n\t\tl1.lock.RLock()\n\t\tfor sel2, l2 := range l1.children {\n\t\t\tlevels = append(levels, l2)\n\t\t\tselectors = append(selectors, []string{sel1, sel2})\n\t\t}\n\t\tl1.lock.RUnlock()\n\t}\n\tm.root.lock.RUnlock()\n\n\ttype workItem struct {\n\t\tlevel    *Level\n\t\thostDir  string\n\t\tselector []string\n\t}\n\n\ttotalWork := len(levels)\n\tcclog.Infof(\"[METRICSTORE]> Starting binary checkpoint for %d hosts with %d workers\", totalWork, Keys.NumWorkers)\n\n\tn, errs, completed := int32(0), int32(0), int32(0)\n\tvar successDirs []string\n\tvar successMu sync.Mutex\n\n\tvar wg sync.WaitGroup\n\twg.Add(Keys.NumWorkers)\n\twork := make(chan workItem, Keys.NumWorkers*2)\n\n\t// Progress logging goroutine.\n\tstopProgress := make(chan struct{})\n\tgo func() {\n\t\tticker := time.NewTicker(10 * time.Second)\n\t\tdefer ticker.Stop()\n\t\tfor {\n\t\t\tselect {\n\t\t\tcase <-ticker.C:\n\t\t\t\tcclog.Infof(\"[METRICSTORE]> Checkpoint progress: %d/%d hosts (%d written, %d errors)\",\n\t\t\t\t\tatomic.LoadInt32(&completed), totalWork, atomic.LoadInt32(&n), atomic.LoadInt32(&errs))\n\t\t\tcase <-stopProgress:\n\t\t\t\treturn\n\t\t\t}\n\t\t}\n\t}()\n\n\tfor range Keys.NumWorkers {\n\t\tgo func() {\n\t\t\tdefer wg.Done()\n\t\t\tfor wi := range work {\n\t\t\t\terr := wi.level.toCheckpointBinary(wi.hostDir, from, to, m)\n\t\t\t\tif err != nil {\n\t\t\t\t\tif err == ErrNoNewArchiveData {\n\t\t\t\t\t\tatomic.AddInt32(&completed, 1)\n\t\t\t\t\t\tcontinue\n\t\t\t\t\t}\n\t\t\t\t\tcclog.Errorf(\"[METRICSTORE]> binary checkpoint error for %s: %v\", wi.hostDir, err)\n\t\t\t\t\tatomic.AddInt32(&errs, 1)\n\t\t\t\t} else {\n\t\t\t\t\tatomic.AddInt32(&n, 1)\n\t\t\t\t\t// Delete WAL immediately after successful snapshot.\n\t\t\t\t\twalPath := path.Join(wi.hostDir, \"current.wal\")\n\t\t\t\t\tif err := os.Remove(walPath); err != nil && !os.IsNotExist(err) {\n\t\t\t\t\t\tcclog.Errorf(\"[METRICSTORE]> WAL remove %s: %v\", walPath, err)\n\t\t\t\t\t}\n\t\t\t\t\tsuccessMu.Lock()\n\t\t\t\t\tsuccessDirs = append(successDirs, wi.hostDir)\n\t\t\t\t\tsuccessMu.Unlock()\n\t\t\t\t}\n\t\t\t\tatomic.AddInt32(&completed, 1)\n\t\t\t}\n\t\t}()\n\t}\n\n\tfor i := range levels {\n\t\thostDir := path.Join(dir, path.Join(selectors[i]...))\n\t\twork <- workItem{\n\t\t\tlevel:    levels[i],\n\t\t\thostDir:  hostDir,\n\t\t\tselector: selectors[i],\n\t\t}\n\t}\n\tclose(work)\n\twg.Wait()\n\tclose(stopProgress)\n\n\tif errs > 0 {\n\t\treturn int(n), successDirs, fmt.Errorf(\"[METRICSTORE]> %d errors during binary checkpoint (%d successes)\", errs, n)\n\t}\n\treturn int(n), successDirs, nil\n}\n\n// toCheckpointBinary writes a binary snapshot file for a single host-level node.\n// Uses atomic rename (write to .tmp then rename) to avoid partial reads on crash.\nfunc (l *Level) toCheckpointBinary(dir string, from, to int64, m *MemoryStore) error {\n\tcf, err := l.toCheckpointFile(from, to, m)\n\tif err != nil {\n\t\treturn err\n\t}\n\tif cf == nil {\n\t\treturn ErrNoNewArchiveData\n\t}\n\n\tif err := os.MkdirAll(dir, CheckpointDirPerms); err != nil {\n\t\treturn fmt.Errorf(\"mkdir %s: %w\", dir, err)\n\t}\n\n\t// Write to a temp file first, then rename (atomic on POSIX).\n\ttmpPath := path.Join(dir, fmt.Sprintf(\"%d.bin.tmp\", from))\n\tfinalPath := path.Join(dir, fmt.Sprintf(\"%d.bin\", from))\n\n\tf, err := os.OpenFile(tmpPath, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, CheckpointFilePerms)\n\tif err != nil {\n\t\treturn fmt.Errorf(\"open binary snapshot %s: %w\", tmpPath, err)\n\t}\n\n\tbw := bufio.NewWriter(f)\n\tif err := writeBinarySnapshotFile(bw, cf); err != nil {\n\t\tf.Close()\n\t\tos.Remove(tmpPath)\n\t\treturn fmt.Errorf(\"write binary snapshot: %w\", err)\n\t}\n\tif err := bw.Flush(); err != nil {\n\t\tf.Close()\n\t\tos.Remove(tmpPath)\n\t\treturn err\n\t}\n\tf.Close()\n\n\treturn os.Rename(tmpPath, finalPath)\n}\n\n// writeBinarySnapshotFile writes the binary snapshot file header and level tree.\nfunc writeBinarySnapshotFile(w io.Writer, cf *CheckpointFile) error {\n\tif err := binary.Write(w, binary.LittleEndian, snapFileMagic); err != nil {\n\t\treturn err\n\t}\n\tif err := binary.Write(w, binary.LittleEndian, cf.From); err != nil {\n\t\treturn err\n\t}\n\tif err := binary.Write(w, binary.LittleEndian, cf.To); err != nil {\n\t\treturn err\n\t}\n\treturn writeBinaryLevel(w, cf)\n}\n\n// writeBinaryLevel recursively writes a CheckpointFile level in binary format.\nfunc writeBinaryLevel(w io.Writer, cf *CheckpointFile) error {\n\tif err := binary.Write(w, binary.LittleEndian, uint32(len(cf.Metrics))); err != nil {\n\t\treturn err\n\t}\n\n\tfor name, metric := range cf.Metrics {\n\t\tif err := writeString16(w, name); err != nil {\n\t\t\treturn err\n\t\t}\n\t\tif err := binary.Write(w, binary.LittleEndian, metric.Frequency); err != nil {\n\t\t\treturn err\n\t\t}\n\t\tif err := binary.Write(w, binary.LittleEndian, metric.Start); err != nil {\n\t\t\treturn err\n\t\t}\n\t\tif err := binary.Write(w, binary.LittleEndian, uint32(len(metric.Data))); err != nil {\n\t\t\treturn err\n\t\t}\n\t\tfor _, v := range metric.Data {\n\t\t\tif err := binary.Write(w, binary.LittleEndian, math.Float32bits(float32(v))); err != nil {\n\t\t\t\treturn err\n\t\t\t}\n\t\t}\n\t}\n\n\tif err := binary.Write(w, binary.LittleEndian, uint32(len(cf.Children))); err != nil {\n\t\treturn err\n\t}\n\n\tfor name, child := range cf.Children {\n\t\tif err := writeString16(w, name); err != nil {\n\t\t\treturn err\n\t\t}\n\t\tif err := writeBinaryLevel(w, child); err != nil {\n\t\t\treturn err\n\t\t}\n\t}\n\n\treturn nil\n}\n\n// writeString16 writes a 2-byte length-prefixed string to w.\nfunc writeString16(w io.Writer, s string) error {\n\tif err := binary.Write(w, binary.LittleEndian, uint16(len(s))); err != nil {\n\t\treturn err\n\t}\n\t_, err := io.WriteString(w, s)\n\treturn err\n}\n\n// loadBinaryFile reads a binary snapshot file and loads data into the Level tree.\n// The retention check (from) is applied to the file's 'to' timestamp.\nfunc (l *Level) loadBinaryFile(m *MemoryStore, f *os.File, from int64) error {\n\tbr := bufio.NewReader(f)\n\n\tvar magic uint32\n\tif err := binary.Read(br, binary.LittleEndian, &magic); err != nil {\n\t\treturn fmt.Errorf(\"[METRICSTORE]> binary snapshot: read magic: %w\", err)\n\t}\n\tif magic != snapFileMagic {\n\t\treturn fmt.Errorf(\"[METRICSTORE]> binary snapshot: invalid magic 0x%08X (expected 0x%08X)\", magic, snapFileMagic)\n\t}\n\n\tvar fileFrom, fileTo int64\n\tif err := binary.Read(br, binary.LittleEndian, &fileFrom); err != nil {\n\t\treturn fmt.Errorf(\"[METRICSTORE]> binary snapshot: read from: %w\", err)\n\t}\n\tif err := binary.Read(br, binary.LittleEndian, &fileTo); err != nil {\n\t\treturn fmt.Errorf(\"[METRICSTORE]> binary snapshot: read to: %w\", err)\n\t}\n\n\tif fileTo != 0 && fileTo < from {\n\t\treturn nil // File is older than retention window, skip it\n\t}\n\n\tcf, err := readBinaryLevel(br)\n\tif err != nil {\n\t\treturn fmt.Errorf(\"[METRICSTORE]> binary snapshot: read level tree: %w\", err)\n\t}\n\tcf.From = fileFrom\n\tcf.To = fileTo\n\n\treturn l.loadFile(cf, m)\n}\n\n// readBinaryLevel recursively reads a level from the binary snapshot format.\nfunc readBinaryLevel(r io.Reader) (*CheckpointFile, error) {\n\tcf := &CheckpointFile{\n\t\tMetrics:  make(map[string]*CheckpointMetrics),\n\t\tChildren: make(map[string]*CheckpointFile),\n\t}\n\n\tvar numMetrics uint32\n\tif err := binary.Read(r, binary.LittleEndian, &numMetrics); err != nil {\n\t\treturn nil, fmt.Errorf(\"read num_metrics: %w\", err)\n\t}\n\n\tfor range numMetrics {\n\t\tname, err := readString16(r)\n\t\tif err != nil {\n\t\t\treturn nil, fmt.Errorf(\"read metric name: %w\", err)\n\t\t}\n\n\t\tvar freq, start int64\n\t\tif err := binary.Read(r, binary.LittleEndian, &freq); err != nil {\n\t\t\treturn nil, fmt.Errorf(\"read frequency for %s: %w\", name, err)\n\t\t}\n\t\tif err := binary.Read(r, binary.LittleEndian, &start); err != nil {\n\t\t\treturn nil, fmt.Errorf(\"read start for %s: %w\", name, err)\n\t\t}\n\n\t\tvar numValues uint32\n\t\tif err := binary.Read(r, binary.LittleEndian, &numValues); err != nil {\n\t\t\treturn nil, fmt.Errorf(\"read num_values for %s: %w\", name, err)\n\t\t}\n\n\t\tdata := make([]schema.Float, numValues)\n\t\tfor i := range numValues {\n\t\t\tvar bits uint32\n\t\t\tif err := binary.Read(r, binary.LittleEndian, &bits); err != nil {\n\t\t\t\treturn nil, fmt.Errorf(\"read value[%d] for %s: %w\", i, name, err)\n\t\t\t}\n\t\t\tdata[i] = schema.Float(math.Float32frombits(bits))\n\t\t}\n\n\t\tcf.Metrics[name] = &CheckpointMetrics{\n\t\t\tFrequency: freq,\n\t\t\tStart:     start,\n\t\t\tData:      data,\n\t\t}\n\t}\n\n\tvar numChildren uint32\n\tif err := binary.Read(r, binary.LittleEndian, &numChildren); err != nil {\n\t\treturn nil, fmt.Errorf(\"read num_children: %w\", err)\n\t}\n\n\tfor range numChildren {\n\t\tchildName, err := readString16(r)\n\t\tif err != nil {\n\t\t\treturn nil, fmt.Errorf(\"read child name: %w\", err)\n\t\t}\n\n\t\tchild, err := readBinaryLevel(r)\n\t\tif err != nil {\n\t\t\treturn nil, fmt.Errorf(\"read child %s: %w\", childName, err)\n\t\t}\n\t\tcf.Children[childName] = child\n\t}\n\n\treturn cf, nil\n}\n\n// readString16 reads a 2-byte length-prefixed string from r.\nfunc readString16(r io.Reader) (string, error) {\n\tvar sLen uint16\n\tif err := binary.Read(r, binary.LittleEndian, &sLen); err != nil {\n\t\treturn \"\", err\n\t}\n\tbuf := make([]byte, sLen)\n\tif _, err := io.ReadFull(r, buf); err != nil {\n\t\treturn \"\", err\n\t}\n\treturn string(buf), nil\n}\n","structuredPatch":[{"oldStart":358,"oldLines":6,"newStart":358,"newLines":7,"lines":["   if walShardRotateChs == nil || walShuttingDown.Load() {","     return","   }","+  deadline := time.After(2 * time.Minute)","   dones := make([]chan struct{}, 0, len(hostDirs))","   for _, dir := range hostDirs {","     done := make(chan struct{})"]},{"oldStart":365,"oldLines":16,"newStart":366,"newLines":18,"lines":["     select {","     case walShardRotateChs[shard] <- walRotateReq{hostDir: dir, done: done}:","       dones = append(dones, done)","-    default:","-      // Channel full or goroutine not consuming — skip this host.","-      cclog.Warnf(\"[METRICSTORE]> WAL rotation skipped for %s (channel full)\", dir)","+    case <-deadline:","+      cclog.Warnf(\"[METRICSTORE]> WAL rotation send timed out, %d of %d hosts remaining\",","+        len(hostDirs)-len(dones), len(hostDirs))","+      goto waitDones","     }","   }","+waitDones:","   for _, done := range dones {","     select {","     case <-done:","     case <-time.After(30 * time.Second):","-      cclog.Warn(\"[METRICSTORE]> WAL rotation timed out, continuing\")","+      cclog.Warn(\"[METRICSTORE]> WAL rotation completion timed out, continuing\")","       return","     }","   }"]}],"userModified":false,"replaceAll":false},"sourceToolAssistantUUID":"7e469f12-0e0c-4250-8784-6f4e81a1795c","userType":"external","entrypoint":"cli","cwd":"/Users/jan/prg/ClusterCockpit/cc-backend","sessionId":"88c65864-3f29-4b06-bbe1-7fab0c4a0142","version":"2.1.86","gitBranch":"hotfix","slug":"warm-enchanting-clarke"}
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+{"parentUuid":"2bf2085c-2b4d-4d27-aa94-da302f37335f","isSidechain":false,"message":{"model":"claude-opus-4-6","id":"msg_013dwx5Ka9Ea8jyFeSeh6mes","type":"message","role":"assistant","content":[{"type":"text","text":"Builds and tests pass. Here's what changed:\n\n**`pkg/metricstore/walCheckpoint.go` — `RotateWALFiles`**:\n- **Before**: Non-blocking send (`default:` skip) — instantly gives up when the 64-slot channel buffer is full, skipping nearly all nodes on large clusters.\n- **After**: Blocking send with a shared 2-minute deadline — waits for the staging goroutine to drain the channel, ensuring all hosts get their WAL rotated. If the deadline expires (shouldn't happen under normal conditions), it logs a warning with the count of remaining hosts and proceeds to wait for already-submitted rotations."}],"stop_reason":"end_turn","stop_sequence":null,"usage":{"input_tokens":1,"cache_creation_input_tokens":138,"cache_read_input_tokens":41001,"output_tokens":153,"server_tool_use":{"web_search_requests":0,"web_fetch_requests":0},"service_tier":"standard","cache_creation":{"ephemeral_1h_input_tokens":138,"ephemeral_5m_input_tokens":0},"inference_geo":"","iterations":[],"speed":"standard"}},"requestId":"req_011CZUxfGvaBXrZXPMKNd1ZC","type":"assistant","uuid":"00485f77-b2fd-43cc-83c9-8ce6d2d5accb","timestamp":"2026-03-28T05:54:42.392Z","userType":"external","entrypoint":"cli","cwd":"/Users/jan/prg/ClusterCockpit/cc-backend","sessionId":"88c65864-3f29-4b06-bbe1-7fab0c4a0142","version":"2.1.86","gitBranch":"hotfix","slug":"warm-enchanting-clarke"}
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+{"type":"file-history-snapshot","messageId":"1c7d6c3e-373a-47aa-9143-dc3d86ea9006","snapshot":{"messageId":"1c7d6c3e-373a-47aa-9143-dc3d86ea9006","trackedFileBackups":{"/Users/jan/.claude/plans/warm-enchanting-clarke.md":{"backupFileName":"0f2be4ae7b984e17@v2","version":2,"backupTime":"2026-03-28T05:55:32.679Z"},"pkg/metricstore/walCheckpoint.go":{"backupFileName":"f5b5b4bac0274f50@v2","version":2,"backupTime":"2026-03-28T05:55:32.679Z"}},"timestamp":"2026-03-28T05:55:32.679Z"},"isSnapshotUpdate":false}
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+{"parentUuid":"040323e0-6933-46d3-a513-b3a01b332a1c","isSidechain":false,"promptId":"c2838676-6c64-4882-8741-21046aae316c","type":"user","message":{"role":"user","content":[{"tool_use_id":"toolu_01HjwVCnrZyq3LuEWn9ntSAA","type":"tool_result","content":"On branch hotfix\nYour branch is up to date with 'origin/hotfix'.\n\nChanges not staged for commit:\n  (use \"git add <file>...\" to update what will be committed)\n  (use \"git restore <file>...\" to discard changes in working directory)\n\tmodified:   pkg/metricstore/walCheckpoint.go\n\nno changes added to commit (use \"git add\" and/or \"git commit -a\")","is_error":false}]},"uuid":"b5453f13-7bfe-4870-b912-e63eb330d5b3","timestamp":"2026-03-28T05:55:35.427Z","toolUseResult":{"stdout":"On branch hotfix\nYour branch is up to date with 'origin/hotfix'.\n\nChanges not staged for commit:\n  (use \"git add <file>...\" to update what will be committed)\n  (use \"git restore <file>...\" to discard changes in working directory)\n\tmodified:   pkg/metricstore/walCheckpoint.go\n\nno changes added to commit (use \"git add\" and/or \"git commit -a\")","stderr":"","interrupted":false,"isImage":false,"noOutputExpected":false},"sourceToolAssistantUUID":"040323e0-6933-46d3-a513-b3a01b332a1c","userType":"external","entrypoint":"cli","cwd":"/Users/jan/prg/ClusterCockpit/cc-backend","sessionId":"88c65864-3f29-4b06-bbe1-7fab0c4a0142","version":"2.1.86","gitBranch":"hotfix","slug":"warm-enchanting-clarke"}
+{"parentUuid":"b5453f13-7bfe-4870-b912-e63eb330d5b3","isSidechain":false,"message":{"model":"claude-opus-4-6","id":"msg_01HzHQDEr2EMyMGs9wnCGqNH","type":"message","role":"assistant","content":[{"type":"tool_use","id":"toolu_013frH2uR4VjftR6QUdaXwsd","name":"Bash","input":{"command":"git diff","description":"Show staged and unstaged changes"},"caller":{"type":"direct"}}],"stop_reason":null,"stop_sequence":null,"usage":{"input_tokens":3,"cache_creation_input_tokens":220,"cache_read_input_tokens":41139,"cache_creation":{"ephemeral_5m_input_tokens":0,"ephemeral_1h_input_tokens":220},"output_tokens":67,"service_tier":"standard","inference_geo":"not_available"}},"requestId":"req_011CZUxjRcZxyw5oA9LYCxQS","type":"assistant","uuid":"79f1093f-ef09-415b-9efa-9a0dbcd842e6","timestamp":"2026-03-28T05:55:36.339Z","userType":"external","entrypoint":"cli","cwd":"/Users/jan/prg/ClusterCockpit/cc-backend","sessionId":"88c65864-3f29-4b06-bbe1-7fab0c4a0142","version":"2.1.86","gitBranch":"hotfix","slug":"warm-enchanting-clarke"}
+{"parentUuid":"79f1093f-ef09-415b-9efa-9a0dbcd842e6","isSidechain":false,"promptId":"c2838676-6c64-4882-8741-21046aae316c","type":"user","message":{"role":"user","content":[{"tool_use_id":"toolu_013frH2uR4VjftR6QUdaXwsd","type":"tool_result","content":"diff --git a/pkg/metricstore/walCheckpoint.go b/pkg/metricstore/walCheckpoint.go\nindex 35a5d6d5..749ff756 100644\n--- a/pkg/metricstore/walCheckpoint.go\n+++ b/pkg/metricstore/walCheckpoint.go\n@@ -358,6 +358,7 @@ func RotateWALFiles(hostDirs []string) {\n \tif walShardRotateChs == nil || walShuttingDown.Load() {\n \t\treturn\n \t}\n+\tdeadline := time.After(2 * time.Minute)\n \tdones := make([]chan struct{}, 0, len(hostDirs))\n \tfor _, dir := range hostDirs {\n \t\tdone := make(chan struct{})\n@@ -365,16 +366,18 @@ func RotateWALFiles(hostDirs []string) {\n \t\tselect {\n \t\tcase walShardRotateChs[shard] <- walRotateReq{hostDir: dir, done: done}:\n \t\t\tdones = append(dones, done)\n-\t\tdefault:\n-\t\t\t// Channel full or goroutine not consuming — skip this host.\n-\t\t\tcclog.Warnf(\"[METRICSTORE]> WAL rotation skipped for %s (channel full)\", dir)\n+\t\tcase <-deadline:\n+\t\t\tcclog.Warnf(\"[METRICSTORE]> WAL rotation send timed out, %d of %d hosts remaining\",\n+\t\t\t\tlen(hostDirs)-len(dones), len(hostDirs))\n+\t\t\tgoto waitDones\n \t\t}\n \t}\n+waitDones:\n \tfor _, done := range dones {\n \t\tselect {\n \t\tcase <-done:\n \t\tcase <-time.After(30 * time.Second):\n-\t\t\tcclog.Warn(\"[METRICSTORE]> WAL rotation timed out, continuing\")\n+\t\t\tcclog.Warn(\"[METRICSTORE]> WAL rotation completion timed out, continuing\")\n \t\t\treturn\n \t\t}\n \t}","is_error":false}]},"uuid":"42d34672-619d-4d9f-b979-b22d35ec8edb","timestamp":"2026-03-28T05:55:36.415Z","toolUseResult":{"stdout":"diff --git a/pkg/metricstore/walCheckpoint.go b/pkg/metricstore/walCheckpoint.go\nindex 35a5d6d5..749ff756 100644\n--- a/pkg/metricstore/walCheckpoint.go\n+++ b/pkg/metricstore/walCheckpoint.go\n@@ -358,6 +358,7 @@ func RotateWALFiles(hostDirs []string) {\n \tif walShardRotateChs == nil || walShuttingDown.Load() {\n \t\treturn\n \t}\n+\tdeadline := time.After(2 * time.Minute)\n \tdones := make([]chan struct{}, 0, len(hostDirs))\n \tfor _, dir := range hostDirs {\n \t\tdone := make(chan struct{})\n@@ -365,16 +366,18 @@ func RotateWALFiles(hostDirs []string) {\n \t\tselect {\n \t\tcase walShardRotateChs[shard] <- walRotateReq{hostDir: dir, done: done}:\n \t\t\tdones = append(dones, done)\n-\t\tdefault:\n-\t\t\t// Channel full or goroutine not consuming — skip this host.\n-\t\t\tcclog.Warnf(\"[METRICSTORE]> WAL rotation skipped for %s (channel full)\", dir)\n+\t\tcase <-deadline:\n+\t\t\tcclog.Warnf(\"[METRICSTORE]> WAL rotation send timed out, %d of %d hosts remaining\",\n+\t\t\t\tlen(hostDirs)-len(dones), len(hostDirs))\n+\t\t\tgoto waitDones\n \t\t}\n \t}\n+waitDones:\n \tfor _, done := range dones {\n \t\tselect {\n \t\tcase <-done:\n \t\tcase <-time.After(30 * time.Second):\n-\t\t\tcclog.Warn(\"[METRICSTORE]> WAL rotation timed out, continuing\")\n+\t\t\tcclog.Warn(\"[METRICSTORE]> WAL rotation completion timed out, continuing\")\n \t\t\treturn\n \t\t}\n \t}","stderr":"","interrupted":false,"isImage":false,"noOutputExpected":false},"sourceToolAssistantUUID":"79f1093f-ef09-415b-9efa-9a0dbcd842e6","userType":"external","entrypoint":"cli","cwd":"/Users/jan/prg/ClusterCockpit/cc-backend","sessionId":"88c65864-3f29-4b06-bbe1-7fab0c4a0142","version":"2.1.86","gitBranch":"hotfix","slug":"warm-enchanting-clarke"}
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diff --git a/a1/ec897216fa/0/metadata.json b/a1/ec897216fa/0/metadata.json
new file mode 100644
index 00000000..0df506d7
--- /dev/null
+++ b/a1/ec897216fa/0/metadata.json
@@ -0,0 +1,33 @@
+{
+  "cli_version": "0.5.0",
+  "checkpoint_id": "a1ec897216fa",
+  "session_id": "88c65864-3f29-4b06-bbe1-7fab0c4a0142",
+  "strategy": "manual-commit",
+  "created_at": "2026-03-28T05:55:48.342411Z",
+  "branch": "hotfix",
+  "checkpoints_count": 1,
+  "files_touched": [
+    "pkg/metricstore/walCheckpoint.go"
+  ],
+  "agent": "Claude Code",
+  "turn_id": "8801a6561e06",
+  "token_usage": {
+    "input_tokens": 26,
+    "cache_creation_tokens": 33789,
+    "cache_read_tokens": 626723,
+    "output_tokens": 6339,
+    "api_call_count": 20
+  },
+  "session_metrics": {
+    "turn_count": 1
+  },
+  "initial_attribution": {
+    "calculated_at": "2026-03-28T05:55:48.263611Z",
+    "agent_lines": 7,
+    "human_added": 0,
+    "human_modified": 0,
+    "human_removed": 0,
+    "total_committed": 7,
+    "agent_percentage": 100
+  }
+}
diff --git a/a1/ec897216fa/0/prompt.txt b/a1/ec897216fa/0/prompt.txt
new file mode 100644
index 00000000..af3082e6
--- /dev/null
+++ b/a1/ec897216fa/0/prompt.txt
@@ -0,0 +1,5 @@
+After a regular checkpoint the following log warning is writte nfor all nodes:  [WARNING]  walCheckpoint.go:343: [METRICSTORE]> WAL rotation skipped for var/metric-checkpoints/fritz/f0748 (channel full)
+Mar 28 06:39:43 monitoring cc-backend[45645]: [WARNING]  walCheckpoint.go:343: [METRICSTORE]> WAL rotation skipped for var/metric-checkpoints/fritz/f2263 (channel full)
+Mar 28 06:39:43 monitoring cc-backend[45645]: [WARNING]  walCheckpoint.go:343: [METRICSTORE]> WAL rotation skipped for var/metric-checkpoints/fritz/f0481 (channel full)
+Mar 28 06:39:43 monitoring cc-backend[45645]: [WARNING]  walCheckpoint.go:343: [METRICSTORE]> WAL rotation skipped for var/metric-checkpoints/fritz/f0708 (channel full)
+Mar 28 06:39:43 monitoring cc-backend[45645]: [WARNING]  walCheckpoint.go:343: [METRICSTORE]> WAL rotation skipped for var/metric-checkpoints/fritz/f0373 (channel full) . Investigate and issue and suggest fixes.
\ No newline at end of file
diff --git a/a1/ec897216fa/metadata.json b/a1/ec897216fa/metadata.json
new file mode 100644
index 00000000..01967545
--- /dev/null
+++ b/a1/ec897216fa/metadata.json
@@ -0,0 +1,25 @@
+{
+  "cli_version": "0.5.0",
+  "checkpoint_id": "a1ec897216fa",
+  "strategy": "manual-commit",
+  "branch": "hotfix",
+  "checkpoints_count": 1,
+  "files_touched": [
+    "pkg/metricstore/walCheckpoint.go"
+  ],
+  "sessions": [
+    {
+      "metadata": "/a1/ec897216fa/0/metadata.json",
+      "transcript": "/a1/ec897216fa/0/full.jsonl",
+      "content_hash": "/a1/ec897216fa/0/content_hash.txt",
+      "prompt": "/a1/ec897216fa/0/prompt.txt"
+    }
+  ],
+  "token_usage": {
+    "input_tokens": 26,
+    "cache_creation_tokens": 33789,
+    "cache_read_tokens": 626723,
+    "output_tokens": 6339,
+    "api_call_count": 20
+  }
+}