Re: [HACKERS] Automatic cleanup of oldest WAL segments with pg_receivexlog

On 2/23/17 8:47 PM, Michael Paquier wrote:

Anything else than measured in bytes either requires a lookup at the
file timestamp, which is not reliable with noatime or a lookup at WAL
itself to decide when is the commit timestamp that matches the oldest
point in time of the backup policy.

An indication that it'd be nice to have a better way to store this information as part of a base backup, or the archived WAL files.

That could be made performance
wise with an archive command. With pg_receivexlog you could make use
of the end-segment command to scan the completely written segment for
this data before moving on to the next one. At least it gives an
argument for having such a command. David Steele mentioned that he
could make use of such a thing.

BTW, I'm not opposed to an end-segment command; I'm just saying I don't think having it would really help users very much.