On Tue, Jan 17, 2023 at 03:22:02PM +0000, HECTOR INGERTO wrote: > > Another case: a transaction COMMITs, and a slightly later transaction reads > the data > > and sets a hint bit. If the snapshot of the file system with the data > directory in it > > is slightly later than the snapshot of the file system with "pg_wal", the > COMMIT might > > not be part of the snapshot, but the hint bit could be. > > > > Then these uncommitted data could be visible if you recover from the > snapshot. > > > > Yours, > > Laurenz Albe > > > > Thank you all. I have it clearer now. > > > > As a last point. Making the snapshot to the WAL dataset first or last would > make any difference? How would you know which WAL snapshot to use, and if there is any missing data between them? I have often wondered if we could document rules where multiple asychronous snapshots would be safe but have never gotten very far. -- Bruce Momjian <bruce@xxxxxxxxxx> https://momjian.us EDB https://enterprisedb.com Embrace your flaws. They make you human, rather than perfect, which you will never be.
