Re: Postgresql 8.3 statistic stadistinct value dead wrong even with default_statistics_target=1000 - Mailing list pgsql-general

From Ron Mayer
Subject Re: Postgresql 8.3 statistic stadistinct value dead wrong even with default_statistics_target=1000
Date
Msg-id 48B8B993.7040704@cheapcomplexdevices.com
Whole thread Raw
In response to Re: Postgresql 8.3 statistic stadistinct value dead wrong even with default_statistics_target=1000  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-general
Tom Lane wrote:
> Maxim Boguk <mboguk@masterhost.ru> writes:
>> [ ndistinct estimates way off ]
>
> Estimating the number of distinct values in a distribution with a long
> tail is just a really hard problem :-(

If I have a table where I know it has this property, is there
any way I can tell autovacuum's ANALYZE to go ahead and scan
the whole table?    ISTM a vacuum_cost_delay throttled full
table scan might be less harmful then a bad ndistinct guess.


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