Fix Prometheus gauge collision for cache_size metric#9729
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brucearctor wants to merge 1 commit intotemporalio:mainfrom
Open
Fix Prometheus gauge collision for cache_size metric#9729brucearctor wants to merge 1 commit intotemporalio:mainfrom
brucearctor wants to merge 1 commit intotemporalio:mainfrom
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The replication progress cache was reusing MutableStateCacheTypeTagValue as its metrics tag, causing its cache_size gauge to overwrite the mutable state cache's gauge (Prometheus last-write-wins). This made it impossible to monitor the actual mutable state cache capacity. Add a dedicated ReplicationProgressCacheTypeTagValue constant and use it in the progress cache, so both caches report their cache_size independently via distinct cache_type label values. Fixes temporalio#9600
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What Changed
The replication progress cache was reusing
MutableStateCacheTypeTagValueas itscache_typemetrics tag, causing itscache_sizegauge to overwrite the mutable state cache's gauge via Prometheus last-write-wins semantics.This made
cache_size{cache_type="mutablestate"}always report128000(the replication progress cache's default size) instead of the actual mutable state cache capacity — particularly misleading whencacheSizeBasedLimit: trueis configured.Fix
ReplicationProgressCacheTypeTagValue = "replication_progress"constant incommon/metrics/metric_defs.goservice/history/replication/progress_cache.goinstead ofMutableStateCacheTypeTagValuecache_typetag valueBoth caches now report their
cache_sizeindependently via distinctcache_typelabel values.Why
This is a one-line behavioral change (plus the new constant and test). It only affects metric label values — no logic, API surface, or persistence changes.
Fixes #9600