Re: Strange replication problem - segment restored from archive but still requested from master

2015-05-22 18:36 GMT+02:00 Piotr Gasidło <quaker(at)barbara(dot)eu(dot)org>:

> 2015-05-22 6:55 GMT+02:00 Fujii Masao <masao(dot)fujii(at)gmail(dot)com>:
> >
> > This problem happens when WAL record is stored in separate two WAL files
> and
> > there is no valid latter WAL file in the standby. In your case, the
> former file
> > is 0000000400004C4D00000090 and the latter is 0000000400004C4D00000091.
> >
> > In this case, the first half of WAL record can be read from the former
> WAL file,
> > but the remaining half not because no valid latter file exists in the
> standby.
> > Then the standby tries to retrieve the latter WAL file via replication.
> > The problem here is that the standby tries to start the replication from
> the
> > starting point of WAL record, i.e., that's the location of the former
> WAL file.
> > So the already-read WAL file is requested via replication.
> > (..)
>
> I currently have wal_keep_segments set to 0.
> Setting this to higher value will help? As I understand: master won't
> delete segment and could stream it to slave on request - so it will
> help.
>

It definitely helps, but the issue could still happen.

> Does this setting delays WAL archiving?
>
>
Nope. It delays recycling.

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Guillaume.
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