Re: [HACKERS] Automatic cleanup of oldest WAL segments withpg_receivexlog

Micahel,

* Michael Paquier (michael.paquier@gmail.com) wrote:
> Is there any interest for a feature like that? I have a non-polished
> patch at hand but I can work on that for the upcoming CF if there are
> voices in favor of such a feature. The feature could be simply
> activated with a dedicated switch, like --clean-oldest-wal,
> --clean-tail-wal, or something like that.

This sounds interesting, though I wouldn't base it on the amount of free
space on the partition but rather some user-set value (eg:
--max-archive-size=50GB or something).

I am a bit dubious about it in general though.  WAL that you don't have
a base backup for or a replica which needs it is really of very limited
value.  I understand your suggestion that it could be used for
'debugging', but that really seems like a stretch to me.  I would also
be concerned that people would set up their systems using this without
fully understanding it, or being prepared to handle what happens when it
kicks in and starts removing WAL that maybe they should have kept for a
base backup or a replica.  At least if we start failing when the
partition is full then they have alerts telling them that the partition
is full and they have a base backup and WAL to bring it forward to
almost current.

Thanks!

Stephen