Re: Relation of indices to ANALYZE

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Bill Moran <wmoran(at)potentialtech(dot)com>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Relation of indices to ANALYZE
Date: 2003-07-17 18:27:16
Message-ID: 5740.1058466436@sss.pgh.pa.us
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Bill Moran <wmoran(at)potentialtech(dot)com> writes:
> Specifically, I'm wondering if I should do
> the ANALYZE before or after I recreate the indexes, or whether it matters.

At the moment it does not matter --- ANALYZE computes statistics for
each column of a table regardless of what indexes exist.

There has been some talk of trying to compute statistics for the
contents of functional indexes. Also, if we ever do anything about
computing multicolumn correlation statistics, we'd likely choose which
ones are worth computing based on the presence of multicolumn indexes.
So if you want to future-proof your code I'd recommend recreating the
indexes before you ANALYZE.

regards, tom lane

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