Gate block-manager historical storage behind PROMPP feature flag#389
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Add compaction plan/result logs, restore missing block-manager TSDB gauges, and cap compaction ranges by max block duration so 2h block setups follow configured bounds. Co-authored-by: Cursor <cursoragent@cursor.com>
Default to the pre-PR-377 historical TSDB path and enable block-manager only with PROMPP_FEATURES=enable_block_manager, keeping PP head+adapter as the write path in both modes. Co-authored-by: Cursor <cursoragent@cursor.com>
Expose prometheus_tsdb_blocks_loaded_by_size to track loaded block size buckets after reload and help diagnose startup spikes caused by unexpected compaction output. Co-authored-by: Cursor <cursoragent@cursor.com>
Replace the size-based gauge with prometheus_tsdb_blocks_loaded_by_duration so legacy TSDB exposes the same block-duration view as block-manager during startup diagnostics. Co-authored-by: Cursor <cursoragent@cursor.com>
Add Grafana panels for loaded block layout and normalize loaded-block duration buckets to 5 minutes in both block-manager and legacy TSDB so duration heatmaps are stable and easy to read. Co-authored-by: Cursor <cursoragent@cursor.com>
Expose loaded-block duration labels in minutes with 1-minute rounding for both block-manager and legacy TSDB paths, and update Grafana panels to query duration_minutes for clearer heatmap grouping. Co-authored-by: Cursor <cursoragent@cursor.com>
Mirror legacy tsdb "Found healthy block" output so operators can see the on-disk block layout when the block manager starts, including each block's normalized duration in minutes. Co-authored-by: Cursor <cursoragent@cursor.com>
Run reload (with deletion) and a single compaction pass sequentially in one goroutine, mirroring tsdb's compact/reload loop. This removes the race where the compactor's independent loop could plan/compact blocks that the manager's reload was concurrently deleting (open meta.json: no such file or directory) and the resulting repeated re-compaction of overlapping blocks (CPU/mmap churn). The compactor no longer runs its own goroutine, ticker or shared mutex: it exposes a one-shot Compact() called by Manager after each reload. Also render the compaction plan as a string in logs (go-kit cannot encode []string). Co-authored-by: Cursor <cursoragent@cursor.com>
When the C++ scrape parser rejects a buffer with invalid UTF-8 (in a HELP text or a label value), print the containing line, the buffer size and the line start offset to stdout. The Go-side buffer is mutated in place during parsing, so the offending bytes can only be inspected reliably here. Co-authored-by: Cursor <cursoragent@cursor.com>
After a successful compaction, immediately reload and compact again instead of waiting for the next ticker interval, so multiple pending compactions converge in one tick (mirroring tsdb's compact/reload loop). Compact now reports whether it did any work to drive the loop. Co-authored-by: Cursor <cursoragent@cursor.com>
Revert the mixin panels and example dashboard JSON added for block duration observability; keep only the code-level metrics and logging. Co-authored-by: Cursor <cursoragent@cursor.com>
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u-veles-a
approved these changes
Jun 26, 2026
Mirror tsdb: if the reload that loads a newly compacted block fails, remove that block so a half-applied compaction does not leave orphaned blocks on disk. Compact now returns the created block ULIDs and the manager removes them on reload failure. Co-authored-by: Cursor <cursoragent@cursor.com>
vporoshok
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Jun 29, 2026
Open the historical backend (tsdb.DB or block.Manager) eagerly during setup for both schemes. The historical path does no WAL replay (the PP head + adapter is the only write path), so the open is as cheap as the block manager's initial reload and there is no need to defer it into the run group. Remove the now-unnecessary dbOpen channel and the startup gating on it in the config loader and head manager; the server storage actor only waits for shutdown and closes the fanout. Simplify tsdbHistoricalStorage now that its db is set at construction. Co-authored-by: Cursor <cursoragent@cursor.com>
Remove the scraper invalid-UTF-8 diagnostic logging (log_invalid_utf8 helper and its call sites) that was added only for stage diagnostics. Update the storage-scheme comment to reference the PROMPP_FEATURES=enable_block_manager feature flag instead of the removed CLI flag. Co-authored-by: Cursor <cursoragent@cursor.com>
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Summary
PROMPP_FEATURES=enable_block_managerWhy
A stage rollout showed a sharp CPU and mmap spike after switching storage behavior, so we need a safer migration path and better visibility before enabling the new scheme by default.
Test plan
devcontainer exec --workspace-folder . --config .devcontainer/arm/devcontainer.json go test -tags stringlabels ./pp/go/storage/block/...devcontainer exec --workspace-folder . --config .devcontainer/arm/devcontainer.json go test -tags stringlabels ./cmd/prometheus/...Made with Cursor