At Wed, 27 Jan 2021 23:10:53 -0800, Noah Misch <n...@leadboat.com> wrote in > On Thu, Jan 28, 2021 at 12:06:27PM +0900, Kyotaro Horiguchi wrote: > > At Wed, 27 Jan 2021 02:48:48 -0800, Noah Misch <n...@leadboat.com> wrote in > > > On Thu, Jan 21, 2021 at 01:23:36AM -0800, Noah Misch wrote: > > > > On Thu, Jan 21, 2021 at 06:02:11PM +0900, Kyotaro Horiguchi wrote: > > > > > Perhaps I'm missing something, but the patch doesn't pass the v5-0001 > > > > > test with wal_level=minimal? > > > > > > > > Correct. The case we must avoid is letting an old snapshot read an > > > > early-pruned page without error. v5-0001 expects "ERROR: snapshot too > > > > old". > > > > The patch suspends early pruning, so that error is not applicable. > > > I studied the sto feature further and concluded that the checker side > > is fine that it always follow the chages of page-LSN. > > > > So what we can do for the issue is setting seemingly correct page LSN > > at pruning or refrain from early-pruning while we are skipping > > WAL. The reason I took the former is I thought that the latter might > > be a problem since early-pruning would be postponed by a long-running > > wal-skipping transaction. > > Yes, that's an accurate summary. > > > So the patch looks fine to me. The commit message mekes sense. > > > > However, is it ok that the existing tests (modules/snapshot_too_old) > > fails when wal_level=minimal? > > That would not be okay, but I'm not seeing that. How did your setup differ > from the following?
I did that with the following temp-conf. However, the tests succeeds when I ran them again with the configuration. Sorry for the noise. autovacuum = off old_snapshot_threshold = 0 wal_level=minimal max_wal_senders=0 wal_skip_threshold=0 regards. -- Kyotaro Horiguchi NTT Open Source Software Center