On 3/14/11 5:51 PM, Tom Lane wrote:
> Josh Berkus <josh@agliodbs.com> writes:
>>> I'm not convinced you can get a sufficiently good estimate from a small
>>> subset of pages.
>
>> Note that if this requires VACUUM rather than ANALYZE, it introduces a
>> problem for data warehousing users, who can go years between vacuums of
>> their largest tables.
>
> It's likely that the default estimate of zero index correlation will
> work just fine for such users ...
No, it isn't. In fact, users with very large tables are the ones
hardest hit by our lack of correlation stats.
-- -- Josh Berkus PostgreSQL Experts Inc.
http://www.pgexperts.com
