Engineering notes on Postgres observability and governed autonomy.https://www.dbexplore.com/enhttps://www.dbexplore.com/blog/pgvector-index-outgrew-memory/https://www.dbexplore.com/blog/pgvector-index-outgrew-memory/Vector search in Postgres degrades quietly. The index crosses RAM, the build runs on disk, recall decays with churn, and none of it raises an alert.Wed, 30 Sep 2026 00:00:00 GMTpgvectorvector-searchpostgres-internalshttps://www.dbexplore.com/blog/aurora-writer-endpoint-can-lie-to-you/https://www.dbexplore.com/blog/aurora-writer-endpoint-can-lie-to-you/CloudWatch measures instances. Your application talks to endpoints. For the minute those disagree, every instance metric looks healthy while writes fail.Wed, 23 Sep 2026 00:00:00 GMTaurorahigh-availabilitymonitoringhttps://www.dbexplore.com/blog/postgres-18-moved-the-wal-io-counters/https://www.dbexplore.com/blog/postgres-18-moved-the-wal-io-counters/pg_stat_wal lost its write and sync columns to pg_stat_io in 18. Nothing errors. The numbers just stop arriving, and most monitoring never notices.Wed, 16 Sep 2026 00:00:00 GMTpostgres-18postgres-internalsmonitoringhttps://www.dbexplore.com/blog/why-we-capped-ourselves-at-rung-2/https://www.dbexplore.com/blog/why-we-capped-ourselves-at-rung-2/We built an action plane and a fail-closed policy gate, then refused to let any action run unattended until it could prove it was reversible. The ladder.Thu, 10 Sep 2026 00:00:00 GMTgoverned-autonomyaction-planepolicy-gatehttps://www.dbexplore.com/blog/75-percent-of-our-plan-storage-was-duplicate/https://www.dbexplore.com/blog/75-percent-of-our-plan-storage-was-duplicate/Thousands of stored plans turned out to be a few hundred distinct shapes. What a structural fingerprint keeps, what it strips, and why regressions depend on it.Thu, 27 Aug 2026 00:00:00 GMTquery-plansplan-regressionpostgres-internalshttps://www.dbexplore.com/blog/what-our-anomaly-engine-actually-runs/https://www.dbexplore.com/blog/what-our-anomaly-engine-actually-runs/An isolation forest with a fixed contamination rate, density clustering with a sample floor, a threshold-ladder classifier, and heuristics that name a cause.Thu, 13 Aug 2026 00:00:00 GMTanomaly-detectionmachine-learningsignatures