Re: Re: [COMMITTERS] pgsql: Make standby server continuously retry restoring the next WAL

Alvaro Herrera wrote:
> Heikki Linnakangas escribió:
>
>> When recovery reaches an invalid WAL record, typically caused by a
>> half-written WAL file, it closes the file and moves to the next source.
>> If an error is found in a file restored from archive or in a portion
>> just streamed from master, however, a PANIC is thrown, because it's not
>> expected to have errors in the archive or in the master.
>
> Hmm, I think I've heard that tools like walmgr do incremental copies of
> the current WAL segment to the archive. Doesn't this change break that?

Hmm, you could have a restore_command that checks the size before
restoring to make it still work. I note that pg_standby does that, but
of course you can't use pg_standby with the built-in standby mode. Or
maybe we should modify the built-in standby mode to handle partial files
coming from restore_command by not throwing an error but recovering to
the end of the partial file, and then retrying restore_command again
with the same filename until the whole file is recovered (or the missing
WAL is received through other means, ie. streaming replication).

--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com