PostgreSQL: Hardening the Wait For LSN Feature
Three separate fixes this cycle target the new Wait For LSN feature, closing a recovery deadlock, a missed wakeup, and a stale-read bug, while Repack and an LLVM build regression got smaller but notable corrections.
Duration: PT2M34S
Episode overview
This episode is a short developer briefing from PostgreSQL.
It explains recent repository work in plain language.
- Show: PostgreSQL
- Published: 2026-09-13T13:02:35Z
- Audio duration: PT2M34S
Transcript excerpt
This excerpt keeps the crawler page concise. Listen to the episode or use the RSS feed for the full update.
Good day, and welcome to the PostgreSQL briefing for September 13th, 2026.
The clear signal today is a concentrated hardening pass on the Wait For LSN feature, with three separate commits from Alexander Korotkov and Xuneng Zhou closing real correctness gaps before this feature sees wider use.
The most serious of the three is commit e0c160c. A backend waiting for replay to catch up can still be holding locks the startup process needs to make progress. Because that wait wasn't registered with the lock manager, the deadlock detector couldn't see the cycle, and with no timeout in place, the deadlock could…
The other two fixes are smaller but in the same neighborhood. Commit d61f9c9 fixes a missed wakeup: when a WAL write implicitly triggers a flush, waiters on primary flush weren't being notified, so they could sleep far longer than necessary. And commit 8c7a74c fixes a race where the standby's position was sampled…
Taken together, these three commits show a feature still being stress-tested against edge cases around recovery, locking, and timing. If you're using Wait For LSN in application logic, the pattern to remember is: don't hold heavyweight locks across a wait, and expect these…
Two…
Nearby episodes from PostgreSQL
- Repack Decoding Bugs and a Schema Feature Retreat
- Correctness Fixes Around Concurrency and Replication
- Correctness Fixes in the Query Planner and Foreign Keys
- Repack Command Gets Locked Down
- A Big Revert and a Round of Correctness Fixes
- Correctness Fixes Land Ahead of Version 19
- Weekly Recap - Query Planner Correctness & Concurrency Cleanup
- Trading Spinlocks for Atomics