pgsql-hackers
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Fix background writer processing locking in README
- Jump to comment-1Henrik TJ<henrik@0x48.dk>Apr 28, 2026, 2:25 PM UTCHi
I was reading through src/backend/storage/buffer/README, and the paragraph about writing out buffers seems not to have been updated after starting to use the share-exclusive lock level, commit 82467f627bd4.
The paragraph in question:
The background writer takes shared content lock on a buffer while writing it
out (and anyone else who flushes buffer contents to disk must do so too).
This ensures that the page image transferred to disk is reasonably consistent.
We might miss a hint-bit update or two but that isn't a problem, for the same
reasons mentioned under buffer access rules.
The attached patch updates this to use shared-exclusive, and removes the consistency bit. Arguably the entire paragraph could be removed, as the issue is covered earlier in the document, but I tried to keep the doc mostly as-is.best regards, Henrik