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Metric time series data expires via the pcp:values:series: stream TTL
(stream.expire, default 86400s), but the ~10 ancillary keys per series
(pcp:desc:series:, pcp:series:metric.name:, pcp:series:label.*.value:,
etc.) accumulated indefinitely, causing unbounded key server growth.
Add pmSeriesGC() to libpcp_web and a --gc / --dryrun mode to pmseries
that scans pcp:desc:series:* for all known series, checks whether each
stream is still alive, and for stale series removes:
- pcp:desc:series:H, pcp:metric.name:series:H
- pcp:instances:series:H, pcp:labelvalue:series:H, pcp:labelflags:series:H
- membership in pcp:series:metric.name:*, pcp:series:inst.name:*,
pcp:series:label.<name>.value:*, pcp:series:context.name:*
- orphaned pcp:inst:series:* hashes when their inst-name set empties
All key server operations are fully async using the existing
baton/callback infrastructure. Three new pmproxy MMV metrics track GC
activity: series.gc.calls, series.gc.scanned, series.gc.cleaned.
Output uses the standard info callback so results appear on stdout for
the CLI and in the pmproxy log when invoked from a timer.
Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>
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Summary
pcp:desc:series:,pcp:series:metric.name:,pcp:series:label.*.value:, etc.) accumulated indefinitely after stream TTL expiry, causing unbounded key server growthpmSeriesGC()to libpcp_web andpmseries --gc/--dryrunto scan for expired series and remove all associated keys asynchronouslyseries.gc.calls,series.gc.scanned,series.gc.cleanedDetails
When
pcp:values:series:Hexpires (viastream.expire, default 86400s) the raw data is reclaimed but ~10 ancillary keys per series remain.--gcscanspcp:desc:series:*, checks each stream's liveness, and for dead series removes:pcp:desc:series:H,pcp:metric.name:series:H,pcp:instances:series:H,pcp:labelvalue:series:H,pcp:labelflags:series:Hpcp:series:metric.name:*,pcp:series:inst.name:*,pcp:series:label.<name>.value:*,pcp:series:context.name:*pcp:inst:series:*hashes when their inst-name set becomes emptyOutput goes through the standard info callback (stdout for CLI, pmproxy log for timer use). A
--dryrunflag logs what would be removed without writing anything.Tested against a local Valkey instance: 9547 series scanned, 8402 identified for cleanup.
Known limitation: SCAN is sent to the first node only (
keySlotsRequestFirstNode); full cluster support is future work.Test plan
pmseries --gc --dryrun— verify series listed without any key server writespmseries --gc— verify ancillary keys removedseries.gc.*MMV metrics visible via pmproxy after a GC run--gcis mutually exclusive with--load,--query,--values,--window--dryrunwithout--gcis rejected with a clear error🤖 Generated with Claude Code