Greetings, * Phil Endecott (spam_from_pgsql_lists@xxxxxxxxxxxx) wrote: > OK. I think this is perhaps a documentation bug, maybe a missing > warning when the master reads its configuration, and maybe (as you say) > a bad default value. If we consider it to be an issue worthy of a change then we should probably just change the default value, and maybe not even allow it to be set lower than '1'. > Specifically, section 26.2.5 of the docs says: > > "If you use streaming replication without file-based continuous archiving, > the server might recycle old WAL segments before the standby has received > them. If this occurs, the standby will need to be reinitialized from a new > base backup. You can avoid this by setting wal_keep_segments to a value > large enough to ensure that WAL segments are not recycled too early, or by > configuring a replication slot for the standby. If you set up a WAL archive > that's accessible from the standby, these solutions are not required, since > the standby can always use the archive to catch up provided it retains enough > segments." > > OR, maybe the WAL reader that process the files that restore_command fetches > could be smart enough to realise that it can skip over the gap at the end? That strikes me as a whole lot more complication in something we'd rather not introduce additional complications into without very good reason. Then again, there was just a nearby discussion about how it'd be nice if the backend could realize when a WAL file is complete, and I do think that'll be more of an issue when users start configuring larger WAL files, so perhaps we should figure out a way to handle this.. > Anyway. Do others agree that my issue was the result of wal_keep_segments=0 ? Yeah, I've not spent much time actually looking at code around this, so it'd be nice to get: a) a reproducible case demonstrating it's happening b) testing to see how long it's been this way c) if setting wal_keep_segments=1 fixes it d) perhaps some thought around if we could address this some other way Thanks! Stephen
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