Re: strange behavior of WAL files - Mailing list pgsql-general

From Atul Kumar
Subject Re: strange behavior of WAL files
Date
Msg-id CA+ONtZ5WnVu4BmQtB5Aw4UapEpG9citT69cXn60=w_GdAyY9Gg@mail.gmail.com
Whole thread Raw
In response to Re: strange behavior of WAL files  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-general
Hi Jehan,

Just to add little more info about this issue is : We have set value
4000  for parameter wal_keep_segments.

So is there any chance that after a certain number of WAL files,
postgres will start recycling the WAL with same name ?



Please share your valuable suggestion.



Regards.
Atul









On 6/4/21, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Atul Kumar <akumar14871@gmail.com> writes:
>> once old WAL files of pg_xlog directory are archived in
>> '/nfslogs/wal/' directory then these WAL files are getting generated
>> with the same name in pg_xlog directory.
>
> Are you sure you are describing the behavior accurately?
>
> What I would expect to happen, once an old WAL file has been archived
> and the server knows its contents are no longer needed, is for the
> WAL file to be "recycled" by renaming it to have a name that's in-the-
> future in the WAL name series, whereupon it will wait its turn to be
> reused by future WAL writes.  On most filesystems the rename as such
> doesn't change the file's mod time, so you'll see files that seem
> to be in-the-future according to their names, but have old timestamps.
>
> (There's a limit on how many future WAL files we'll tee up this way,
> so it's possible that an old one would just get deleted instead.
> But the steady-state behavior is to just rotate them around.)
>
>             regards, tom lane
>



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