Re: warning message in standby

On Thu, 2010-06-10 at 19:01 +0300, Heikki Linnakangas wrote:
> >
> > What "warning message" are we talking about? All the error cases I can
> > think of in WAL-application are ERROR, or likely even PANIC.
>
> We're talking about a corrupt record (incorrect CRC, incorrect backlink
> etc.), not errors within redo functions. During crash recovery, a
> corrupt record means you've reached end of WAL. In standby mode, when
> streaming WAL from master, that shouldn't happen, and it's not clear
> what to do if it does. PANIC is not a good idea, at least if the server
> uses hot standby, because that only makes the situation worse from
> availability point of view. So we log the error as a WARNING, and keep
> retrying. It's unlikely that the problem will just go away, but we keep
> retrying anyway in the hope that it does. However, it seems that we're
> too aggressive with the retries.

If my streaming replication stops working, I want to know about it as
soon as possible. WARNING just doesn't cut it.

This needs some better thought.

If we PANIC, then surely it will PANIC again when we restart unless we
do something. So we can't do that. But we need to do something better
than

WARNING there is a bug that will likely cause major data loss
HINT you'll be sacked if you miss this message

--
Simon Riggs www.2ndQuadrant.com
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