Hi Sami, On Wed, Sep 9, 2026 at 5:42 AM Sami Imseih <[email protected]> wrote:
> The WAIT FOR docs say that "The standby_replay mode waits for the LSN to be > replayed (applied to the database), which is useful to achieve > read-your-writes > consistency while using an async replica for reads and the primary for > writes." > > I think that needs one more caveat. > > WAIT FOR success does not guarantee read-your-writes if the supplied LSN > is before the transaction's COMMIT record. > > Maybe the last sentence should be qualified with: > > " .... the primary for writes, provided that the target LSN was > captured after COMMIT on the primary." > > This may be obvious to users of this feature, but perhaps worth being > more explicit about it. > > Thoughts? Thanks for raising this! I agree this may need to be harnessed. If we change this line, we might also want to modify the read-your-writes-consistency chapter. <sect2 id="read-your-writes-consistency"> <title>Read-Your-Writes Consistency</title> I am also wondering whether a example like this is helpful, though it is somehow duplicated with the existing one: postgres=# BEGIN; BEGIN postgres=*# UPDATE movie SET genre = 'Dramatic' WHERE genre = 'Drama'; UPDATE 100 postgres=*# COMMIT; COMMIT postgres=# SELECT pg_current_wal_insert_lsn(); -- Regards, Xuneng Zhou HighGo Software Co., Ltd.
