{"Entry":{"collection":"guc","key":"track_commit_timestamp","name":"track_commit_timestamp","aliases":[],"metadata":{"baseline":false,"boot_human":"Not specified","boot_val":null,"category":"Replication / Sending Servers","category_zh":"","changed_in":["14"],"changes":[{"documentation_changed":false,"fields":{},"from":"9.4","status":"added","to":"9.5"},{"documentation_changed":true,"fields":{},"from":"12","status":"changed","to":"13"},{"documentation_changed":false,"fields":{"category":{"from":"Replication","to":"Replication / Sending Servers"}},"from":"13","status":"changed","to":"14"}],"content_hash":"83b3f63612bb70847f26b78aa3d1d2cf38d8e9faf168e1b8dc877666c9b207e2","context":"","default_changed_in":[],"default_history":[{"from":"9.5","to":"19","value":"off"}],"derived_content_hash":"2698a6ab02181d73a2b6cde9796a733fc0e3385b56c0b63e70b3c98f2656ce05","documentation_refresh":{"batch":"20261113","original_source_rev":"wiki-repair-20261023:9ee4c7c8ddd4416fbc7d856d2f3b623bceb4499b0e7a52801a6a154f4cf709ab","versions":{"14":"14.25","15":"15.20","16":"16.16","17":"17.12","18":"18.7","19":"19rc2"}},"editorial":{"advice":{"olap":"Read standbys and logical subscribers often see long queries or large transactions. Put explicit bounds on replay/apply and monitor lag, worker saturation, slot restart_lsn, and conflict cancellations.","oltp":"Size track_commit_timestamp from topology, failover roles, slot/subscription count, and reconnect headroom. Test worst-case primary latency, standby replay, and disk retention before production.","small":"Configure only replication capacity that is actually used. Even a small topology needs bounded timeouts and slot lifecycle; unlimited retention is not reliability."},"mechanism":["Collects transaction commit time. The value is fixed when the server starts, so changing it requires a restart.","PostgreSQL stores transaction commit timestamps in an auxiliary SLRU so SQL and replication-origin features can query them later. It must be enabled at startup before the history is collected and adds storage/I/O overhead; it cannot reconstruct older timestamps.","Monitor and change track_commit_timestamp together with max_active_replication_origins, max_logical_replication_workers, max_replication_slots. Validate on the relevant server role and real workload, then use its postmaster context to choose session change, reload, or restart; a historical boot default is not the current effective value."],"pitfalls":["Changing it on the wrong primary, standby, sender, or subscriber role.","Watching only configured bytes/time instead of actual lag, slot position, and worker state.","Failing over to a node that lacks the old primary's capacity or prerequisites.","Using infinite waits or WAL retention to hide a failed consumer."],"references":[{"title":"PostgreSQL 19 Beta 4: track_commit_timestamp","url":"https://www.postgresql.org/docs/19/runtime-config-replication.html#GUC-TRACK-COMMIT-TIMESTAMP"},{"title":"PostgreSQL 19 release notes","url":"https://www.postgresql.org/docs/19/release-19.html"}],"related":["max_active_replication_origins","max_logical_replication_workers","max_replication_slots","idle_replication_slot_timeout","max_slot_wal_keep_size","max_wal_senders"],"summary":"track_commit_timestamp — Collects transaction commit time. Observed in PG9.5–19 Beta 4; its last measured boot default is off in PG19 Beta 4, with postmaster context. This is a beta-snapshot fact and can change before PostgreSQL 19 GA."},"enumvals":[],"first_version":"9.5","group":"Replication","group_slug":"replication","imported_at":"2026-09-27T17:57:32.209127+08:00","intro_commit":{"authored_at":"2014-12-03T11:53:02-03:00","discussion":[],"hash":"73c986adde5d73a5e2555da9b5c8facedb146dcd","subject":"Keep track of transaction commit timestamps","url":"https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=73c986adde5d73a5e2555da9b5c8facedb146dcd"},"key":"track_commit_timestamp","last_version":"20","max_val":"","min_val":"","name":"track_commit_timestamp","position":427,"present_in":["9.5","9.6","10","11","12","13","14","15","16","17","18","19","20"],"repair_provenance":{"original_source_revision":"english-manuals:3a9f47d5d170c996f55622b7c2ddc11c7cf79489dcb94645c9e5cd4c9183cd3e","receipt_sha256":"84403ad80960c670a9589fb565cb6d2ce5fd55d49308875f8eff364bf7d0417a","repair":"wiki-repair-20261023"},"short_desc":"Record commit time of transactions.","short_desc_zh":"","source_rev":"wiki-repair-20261023:9ee4c7c8ddd4416fbc7d856d2f3b623bceb4499b0e7a52801a6a154f4cf709ab","unit":"","vartype":"bool"}},"Definition":{"Collection":"guc","Key":"track_commit_timestamp","SourceDatabase":"center","Version":"18","SourceTable":"guc","SourceKey":"track_commit_timestamp","SourceRevision":"wiki-repair-20261023:9ee4c7c8ddd4416fbc7d856d2f3b623bceb4499b0e7a52801a6a154f4cf709ab","Facts":{"boot_val":"off","category":"Replication / Sending Servers","context":"postmaster","description":"Record commit time of transactions. 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