Re: Wal logs continued...

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: webb sprague <wsprague(at)o1(dot)com>
Cc: PostgreSQL-General <pgsql-general(at)postgresql(dot)org>
Subject: Re: Wal logs continued...
Date: 2001-05-15 02:23:48
Message-ID: 28484.989893428@sss.pgh.pa.us
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webb sprague <wsprague(at)o1(dot)com> writes:
> Unfortunately, the problem snow seems to happen when I vacuum-analyze
> after a big delete. Even if the vacuum takes more than 2 minutes (the
> amount of time between flushes that I set in postgresql.conf), the
> logs continue to grow.

I don't think there's any way around that at the moment :-(. The old
log segments cannot be deleted as long as they include information about
as-yet-uncommitted transactions, and the VACUUM is one big transaction.

It would theoretically be possible to delete old log segments from
before the last checkpoint (or better, next-to-last checkpoint) if
we were only concerned about using the logs for crash recovery.
I imagine Vadim will object to that, however, since he has in mind
using the logs for UNDOing aborted transactions sometime soon.

A more likely solution path will be to eliminate VACUUM or break it
into smaller transactions...

regards, tom lane

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