Обсуждение: Auto Vacuum question?

i set the auto vacuum option to enable. but my database size(hard-disk
space) still increased from 420MB to 440MB in 8 hours. most of the
operations in this database are the "Select" query command, just few
of "Update or Insert".
why it can be increased so strongly?
after i executed the command " vaccumdb -f -z testdb", but the size
just decreased 1 or 2MB...
what's the problem?
how to know which command(select,insert....) takes the hurge loading
to database in this time?

computer environment:
System: Red Hat Enterprise 4
Postgresql Server: 8.0.13
count of client connected : about 100 pc

On Mon, Jun 04, 2007 at 04:15:12AM -0700, ivan.hou@msa.hinet.net wrote:
> after i executed the command " vaccumdb -f -z testdb", but the size
> just decreased 1 or 2MB...
> what's the problem?

vacuumdb -f does a FULL vacuum, which is blocking and compacts the
tables.  If it only compacted 1 or 2 M, then there are two
possibilities:

1.    You really do have that much data.  You haven't told us
anything about the data, what it looks like, how wide the tables are,
whether you have large objects &c., whether the character set is
multibyte. . .

2.    You have at least one long-running transaction that is
perhaps doing nothing, but that is preventing VACUUM from recovering
space.  What does ps -auxww | grep postgres (or something equivalant)
show you?

A

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Andrew Sullivan  | ajs@crankycanuck.ca
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