Re: Understanding wal segments

On Thursday 01 November 2007 22:38:02 Tom Lane wrote:
> Kevin Kempter <kevin(at)kevinkempterllc(dot)com> writes:
> > What's the relationship between wal_buffers and checkpoint_segments?
>
> None particularly.
>
> > even
> > though the max distance between checkpoints is 32 segments, is there
> > something that controls the number of files/segments in the pg_xlog dir ?
>
> The system is designed to settle at 2*checkpoint_segments+1 files in
> pg_xlog, assuming that you have activity spikes sufficient to drive it
> up to that level at all.
>
> regards, tom lane
>
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makes sense. our system cetrtianly has the activity needed to push it to that
level. I turned on wal archivint 1hr & 10min ago and I already have 135 wal
segments in my archive directory. I'm running a file system backup, I did a
pg_start_backup and now I'm running the tar. Will this affect the transaction
activity? I thought it would not.

Also I suspect after each filesystem backup I should remove the older archived
segments since the file system backup makes them irrelevant. Is this
accurate?

Thx

/Kevin