Обсуждение: Error message in wal_log for Streaming replication

Hi All,

We have been trying to implement the streaming replication on one of our test servers. We have set archive_xlogs to on. But on the standby server,  when we start the database we get error the following errors:

LOG:  shutting down
LOG:  database system is shut down
LOG:  database system was shut down in recovery at 2010-10-05 05:05:27 EDT
LOG:  entering standby mode
cp: cannot stat `/home/postgres/archive_xlogs/000000010000000D00000036': No such file or directory
LOG:  consistent recovery state reached at D/36000078
LOG:  database system is ready to accept read only connections
LOG:  invalid record length at D/36000078
cp: cannot stat `/home/postgres/archive_xlogs/000000010000000D00000036': No such file or directory
LOG:  streaming replication successfully connected to primary

The file "000000010000000D00000036" is seen in pg_xlog folder of the primary database, but is not yet pushed to the archive location.

Can you let us know what the error means and if we are doing anything wrong?

Regards,
Nimesh.

On Tue, 2010-10-05 at 14:41 +0530, Nimesh Satam wrote:
> We have been trying to implement the streaming replication on one of
> our test servers. We have set archive_xlogs to on. But on the standby
> server,  when we start the database we get error the following errors:
>
> LOG:  shutting down
> LOG:  database system is shut down
> LOG:  database system was shut down in recovery at 2010-10-05 05:05:27
> EDT
> LOG:  entering standby mode
> cp: cannot stat
> `/home/postgres/archive_xlogs/000000010000000D00000036': No such file
> or directory
> LOG:  consistent recovery state reached at D/36000078
> LOG:  database system is ready to accept read only connections
> LOG:  invalid record length at D/36000078
> cp: cannot stat
> `/home/postgres/archive_xlogs/000000010000000D00000036': No such file
> or directory
> LOG:  streaming replication successfully connected to primary
>
> The file "000000010000000D00000036" is seen in pg_xlog folder of the
> primary database, but is not yet pushed to the archive location.
>
> Can you let us know what the error means and if we are doing anything
> wrong?

[ this question is more appropriate on pgsql-general ]

Those aren't postgres error messages, those are error messages generated
by "cp".

See:
http://www.postgresql.org/docs/9.0/static/archive-recovery-settings.html

"The command will be asked for file names that are not present in the
archive; it must return nonzero when so asked."

So, it is safe to ignore those errors.

Personally, I would use a restore_command that is silent when the file
doesn't exist so that it doesn't pollute your logs. I'm not sure why the
documentation suggests "cp".

Regards,
    Jeff Davis