On Tue, Feb 4, 2025 at 10:20 AM Masahiko Sawada <sawada.m...@gmail.com> wrote: > > On Tue, Feb 4, 2025 at 12:59 AM Masahiko Sawada <sawada.m...@gmail.com> wrote: > > > > On Sun, Feb 2, 2025 at 8:11 PM Amit Kapila <amit.kapil...@gmail.com> wrote: > > > > > > On Fri, Jan 24, 2025 at 4:05 AM Masahiko Sawada <sawada.m...@gmail.com> > > > wrote: > > > > > > > > When a standby replays a XLOG_PARAMETER_CHANGE record that lowers > > > > wal_level from logical, we invalidate all logical slots only when the > > > > standby is in hot standby mode: > > > > > > > > if (InRecovery && InHotStandby && > > > > xlrec.wal_level < WAL_LEVEL_LOGICAL && > > > > wal_level >= WAL_LEVEL_LOGICAL) > > > > InvalidateObsoleteReplicationSlots(RS_INVAL_WAL_LEVEL, > > > > 0, InvalidOid, > > > > InvalidTransactionId); > > > > > > > > However, it's possible that this record is replayed when not in hot > > > > standby mode and the slot is used after the promotion. In this case, > > > > the following Assert in xlog_decode() fails: > > > > > > > > /* > > > > * This can occur only on a standby, as a primary would > > > > * not allow to restart after changing wal_level < logical > > > > * if there is pre-existing logical slot. > > > > */ > > > > > > Shouldn't we do similar to what this comment indicates on standby? We > > > can disallow to start the server as standby, if the hot_standby is off > > > and there is a pre-existing logical slot. > > > > It seems like a better idea. I thought we could pass StandbyMode to > > StartupReplicationSlots() and check if there is a pre-existing logical > > slot, but it would break the ABI compatibility. It might not be a > > problem in practice as StartupReplicationSlots() is normally used only > > by the startup process. But if we want to avoid that we can introduce > > a new function for that. > > Since StandbyMode is exposed, we don't need to change the function > signature. I'll update and submit the patch soon. >
I've attached the updated patch. The fix needs to be back-patched to v16 where logical decoding on standby was introduced. Regards, -- Masahiko Sawada Amazon Web Services: https://aws.amazon.com
v1-0001-Fix-assertion-when-decoding-XLOG_PARAMETER_CHANGE.patch
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