Re: Postgres 8.3 archive_command

On Wed, 2007-11-21 at 14:45 +0100, Rudolf van der Leeden wrote:

> In v8.2.4 we are currently switching archiving on/off on the fly by
> just inserting an archiving command.
> Now we have got a separate option for handling the on/off state.
> That's ok.
> But the note "change requires restart" is a serious change over v8.2.

Thanks for the feedback.

There was a window of data loss caused by the capability to change the
archive_command on and off while running a large COPY, CTAS, CLUSTER or
CREATE INDEX, which we had to avoid.

The new way of doing this changes that so you must have archive_mode set
on always, but you can still change archive_command on the fly.

> - The workaround is a script that simply does a NOOP if archiving
> is effectively disabled while archive_mode=on all the time.
> How can one switch off the archiving log messages?

You can't.

I think if you choose to set archive command to something that doesn't
actually archive the file, thats up to you. The server log shows that
Postgres server did as you asked it to do. That helps to avoid
complaints like "How come Postgres didn't tell me when it wasn't
archiving".

Perhaps we should move the successful archived message to DEBUG1 now,
except for the first message after the archiver starts or when the
archive_command changes, plus one message every 255 segments? That would
reduce the log volume in the normal case without endangering our ability
to see what is happening.

--
Simon Riggs
2ndQuadrant http://www.2ndQuadrant.com