Re: WAL logs and segment files

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: Eduardo Leva <eeeggg499(at)netscape(dot)net>
Cc: pgsql-admin(at)postgresql(dot)org
Subject: Re: WAL logs and segment files
Date: 2004-02-20 20:29:23
Message-ID: 200402202029.i1KKTNJ22723@candle.pha.pa.us
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Eduardo Leva wrote:
> Hi, guys... I'm reading the version 7.3.4 documentation and I found this: "
>
> "WAL logs are stored in the directory $PGDATA/pg_xlog, as a set of segment
> files, each 16 MB in size. Each segment is divided into 8 kB pages. The
> log record headers are described in access/xlog.h; record content is
> dependent on the type of event that is being logged. Segment files are
> given ever-increasing numbers as names, starting at 0000000000000000. The
> numbers do not wrap, at present, but it should take a very long time to
> exhaust the available stock of numbers. "
>
> in item 12.2 Implementation. The question is: How do I solve this
> situation, the remarked situation? The answer is not in the docs. Thanks.

What situation do you need to solve? The wrapping? The documention
states "a very long time", but it more of a joke. That number would be
huge to wrap around and you would be updating your PostgreSQL version
long before it would ever wrap.

The number is actually an int8 that has a maximum value of:

18446744073709551616

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