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Why does my query drop from 3ms to 4 seconds on Tuesday with no deploy?

78

Opportunità

PostgreSQL's query planner re-evaluates execution plans whenever table statistics change, which happens asynchronously through autovacuum and ANALYZE, independent of any code deployment. A batch import, a routine vacuum after deletion, or a gradual shift in data distribution can flip an index scan to a sequential scan overnight, turning a 3ms query into a 4-second one with no error emitted and no deployment in the history. These regressions are invisible in CI because they are driven by statistics state, not code state, and no standard test harness captures plans across different statistics snapshots. Pganalyze and similar tools detect plan flips after they occur in production, but there is no upstream gate that tests query plan stability before a schema change or data migration ships. PostgreSQL proposed the pg_plan_advice contrib module in October 2025 to let operators hint or pin plan

Perché è importante

Silent query plan regressions are one of the most common causes of unexplained production latency spikes and they remain undetectable until a user reports slowness.

Come valuto l'opportunità

L'Opportunity Score è la mia valutazione personale, non una misurazione: quanto fa male, con quale frequenza colpisce e quanto poco esiste per risolverlo oggi. Un punteggio più alto significa che lo ritengo più degno di essere sviluppato.

Gravità7/10

Quanto dolore provoca quando si manifesta.

Frequenza8/10

Quanto spesso le persone ci si imbattono davvero.

Spazio bianco7/10

Quanti pochi strumenti validi esistono oggi per affrontarlo.

Altri problemi che vale la pena risolvere