Re: Problem with inherited tables vs query planning
От | Dave Golombek |
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Тема | Re: Problem with inherited tables vs query planning |
Дата | |
Msg-id | 20070518143534.5CE615C4512@smtp.blackducksoftware.com обсуждение исходный текст |
Ответ на | Re: Problem with inherited tables vs query planning (Tom Lane <tgl@sss.pgh.pa.us>) |
Ответы |
Re: Problem with inherited tables vs query planning
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Список | pgsql-general |
Tom Lane writes: > "Dave Golombek" <daveg@blackducksoftware.com> writes: > > Is there a way I can reformulate the query to help the planner use the > > indices? > > Use 8.2. Also put an index on the base table, not only the children --- > the forced seqscan on the base weighs down the cost estimate for the > plan you would like to have. (With sufficiently large child tables, > that might not matter, but it sure does for this toy example.) Ah, I forgot to try the index on the base table using 8.2, which does indeed solve the problem. It unfortunately doesn't help with 8.1.4, which we have in the field; any thoughts on workarounds for older versions or should I just use a function until we can upgrade everywhere? We have 150 million rows spread across 16 child tables, which should help cost estimation. Thanks, Dave
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