Re: Call closed: Almost happy ending (from "Data files became huge with no apparent reason" thread)

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Dario Fumagalli <dfumagalli(at)tin(dot)it>
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: Call closed: Almost happy ending (from "Data files became huge with no apparent reason" thread)
Date: 2002-09-03 14:32:47
Message-ID: 5958.1031063567@sss.pgh.pa.us
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Dario Fumagalli <dfumagalli(at)tin(dot)it> writes:
> - Given that single user REINDEX [database name] FORCE in single user
> modedid rebuild the indexes but did not optimize them;
> - Given that a REINDEX INDEX [index name] did optimize and shrink a
> single index but increased the overall data size;
> - Given that a VACUUM VERBOSE ANALYZE somehow alters the overall
> database files size (seems to re-distribute the file space evenly across
> indexes);

There is no such thing as a "reindex that optimizes" versus "reindex
that doesn't optimize". A rebuild is a rebuild. I suspect that you
were fooled by out-of-date relpages statistics in pg_class, and/or
expecting REINDEX to rebuild indexes it won't.

VACUUM updates relpages to reflect current reality, but I'm not sure
whether REINDEX does.

Also, REINDEX at the database level only reindexes system-table indexes.

regards, tom lane

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