Re: Thoughts on maintaining 7.3

Bruce Momjian <pgman@candle.pha.pa.us>

From: Bruce Momjian <pgman@candle.pha.pa.us>
To: Bruce Momjian <pgman@candle.pha.pa.us>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Alvaro Herrera <alvherre@dcc.uchile.cl>, "Joshua D. Drake" <jd@commandprompt.com>, pgsql-hackers@postgresql.org
Date: 2003-10-09T19:34:27Z
Lists: pgsql-hackers
Bruce Momjian wrote:
> > The reason I'm waffling about whether the problem is completely fixed or
> > not is that the existing code will only remove-and-recycle completely
> > empty btree pages.  As long as you have one key left on a page it will
> > stay there.  So you could end up with ridiculously low percentage-filled
> > situations.  This could be fixed by collapsing together adjacent
> > more-than-half-empty pages, but we ran into a lot of problems trying to
> > do that in a concurrent fashion.  So I'm waiting to find out if real
> > usage patterns have a significant issue with this or not.
> 
> If we have an exclusive lock during VACUUM FULL, should we just collapse
> the pages rather than REINDEX?  I realize we might have lots of expired
> index tuples because VACUUM FULL creates new ones as part of
> reorganizing the heap.

Never mind --- I remember now that we are going to use VACUUM for a few
updates, and VACUUM FULL for big updates.

-- 
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