Re: Vacuum only with 20% old tuples

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

From: Bruce Momjian <pgman@candle.pha.pa.us>
To: Andrew McMillan <Andrew@catalyst.net.nz>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, PostgreSQL-development <pgsql-hackers@postgreSQL.org>
Date: 2000-07-12T13:37:36Z
Lists: pgsql-hackers
> I can see some value in having a _configurable_ threshold %age of
> deletes before vacuum kicked in and attempted to shrink table/index
> on-disk file sizes.  This would let the end-user decide, and 20% is
> probably a reasonable default, but if it isn't then changing a default
> is easier to do down the track.
> 
> I can also see that it could be done with (perhaps) a modification to
> VACUUM syntax, say:
> 	VACUUM [VERBOSE] [SHRINK] ...
> 
> And I believe that the whole thing will go better if ANALYZE is taken
> _out_ of vacuum, as was discussed on this list a month or two ago.

The analayze process no longer locks the table exclusively.  It will be
made a separate command in 7.1, though an ANALYZE option will still be
avaiable in VACUUM.

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