Re: pg_xlog question - Mailing list pgsql-novice

From Tom Lane
Subject Re: pg_xlog question
Date
Msg-id 10049.1026487847@sss.pgh.pa.us
Whole thread Raw
In response to pg_xlog question  (Pam Wampler <Pam_Wampler@taylorwhite.com>)
List pgsql-novice
Pam Wampler <Pam_Wampler@taylorwhite.com> writes:
> 1.  what parameter tells postgress to always keep 7 files in the pg_xlog
> directory? (see below) --this is test database we
> are learning on. (and it seems everytime that I look at this directory there
> are always 7 entries there)

It's basically 2 * checkpoint_segments + 1.  See
http://www.ca.postgresql.org/users-lounge/docs/7.2/postgres/wal-configuration.html

> 2.  What happens when the files increment and can no longer increment to a
> higher number (the file name)?

Trouble, which is why we use a 64-bit counter.

> 3.  Is there a way to "reset" the number so that this won't happen?

initdb.  However, you're not gonna have to worry about it in your
lifetime.  Do the math...

            regards, tom lane

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