PostgreSQL: Race Conditions Under Concurrency

Nine backpatched fixes landed today, most addressing race conditions where concurrent operations—dropped tables, database drops, background worker restarts, sequence sync—could cause crashes, replication failures, or resource exhaustion. The common thread: code that assumed stability during a lookup, when another process could change things underneath it.

Duration: PT2M35S

Episode overview

This episode is a short developer briefing from PostgreSQL.

It explains recent repository work in plain language.

  • Show: PostgreSQL
  • Published: 2026-07-29T13:03:28Z
  • Audio duration: PT2M35S

Transcript excerpt

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Good evening. It's July 29th, and today's PostgreSQL activity is dominated by a single theme: what happens when the database changes state out from under a running operation.

Start with logical replication. Masahiko Sawada fixed pg publication tables, which was crashing when a table got dropped mid-query, common during subscriber-side table sync. The fix, in commit 63e7a0d, switches to a safe table open that just skips vanished tables instead of erroring out. Sawada also fixed a second…

Second theme: locking discipline under concurrent DDL. Amit Kapila's commit c12c101 fixes a sequence sync worker that held row-exclusive locks on every sequence it was inspecting, risking "out of shared memory" errors on databases with many sequences. It now takes only an access-share lock, released immediately.…

Third theme: database lifecycle edge cases, all from Daniel Gustafsson. Commit 51f55b1 makes checksum-enable handle invalid or concurrently dropped databases instead of aborting the whole run. Commit 153ca22 closes a window where create-database's file-copy path could raw-copy a template before checksums were…

Two more worth flagging: Tom Lane fixed a planner bug in commit 239eabd where…

What's…

Nearby episodes from PostgreSQL

  1. Correctness Fixes Across Vacuum, Indexing, and Replication
  2. Logical Replication Cleanup Continues
  3. Weekly Recap - Logical Replication Hardening & Test Coverage
  4. Hardening the B-tree Index Under Concurrency
  5. Getting Permission Checks Right
  6. Publication Testing and Docs Get a Cleanup
  7. Version 19's Growing Pains
  8. Polish Pass on Messages and Edge Cases