On Fri, Jul 25, 2025 at 9:57 AM Jon Zeppieri <zeppi...@gmail.com> wrote:
> Thanks for the response, Nick. I'm curious why the situation you describe > wouldn't also lead to the write_lag and flush_lag also being > high. If the problem is simply keeping up with the primary, wouldn't you > expect all three lag times to be elevated? > No - write and flush are pretty quick and simple, it's just putting the WAL onto the local disk. Replay involves a lot more work as we have to parse the WAL and apply the changes, which means doing a lot of I/O across many files. Still, *hours* to me indicates more than just a lot of extra traffic. Check that recovery_min_apply_delay is still 0, then log onto the replica and see what's going on with regards to open transactions and locks. Cheers, Greg -- Crunchy Data - https://www.crunchydata.com Enterprise Postgres Software Products & Tech Support
