Thread: pg_clog question.

pg_clog question.

From
Chris Bowlby
Date:
Hi All, 
I've been noticing that files in the pg_clog directory test to stay
around forever, I know they are used to determine the state of
transaction id's, but according to the docs:
"(However, the urgency of this concern has decreased greatly with the
adoption of a segmented storage method for pg_clog: it is no longer
necessary to keep old pg_clog entries around forever.)"
How does one determine which files are no longer neccessary? Is the
system configured to clear out stale ones during startup/shutdown?

-- 
Chris Bowlby <chris@pgsql.com>
PostgreSQL Inc.



Re: pg_clog question.

From
Chris Bowlby
Date:
Ahh, perfect, thank you..

On Tue, 2004-04-27 at 16:18, Alvaro Herrera wrote:
> On Tue, Apr 27, 2004 at 09:26:38AM -0300, Chris Bowlby wrote:
> 
> >  I've been noticing that files in the pg_clog directory test to stay
> > around forever, I know they are used to determine the state of
> > transaction id's, but according to the docs:
> > 
> >  "(However, the urgency of this concern has decreased greatly with the
> > adoption of a segmented storage method for pg_clog: it is no longer
> > necessary to keep old pg_clog entries around forever.)"
> > 
> >  How does one determine which files are no longer neccessary?
> 
> You don't.  They are deleted on VACUUM FULL when they are no longer
> needed.
> 
> > Is the system configured to clear out stale ones during
> > startup/shutdown?
> 
> No need to take the server down.
-- 
Chris Bowlby <chris@pgsql.com>
PostgreSQL Inc.