| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Lukas Smith <mls(at)pooteeweet(dot)org> |
| Cc: | Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>, pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: Automatic function replanning |
| Date: | 2005-12-18 03:59:07 |
| Message-ID: | 12832.1134878347@sss.pgh.pa.us |
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| Lists: | pgsql-hackers |
Lukas Smith <mls(at)pooteeweet(dot)org> writes:
> Bruce Momjian wrote:
>> * Flush cached query plans when the dependent objects change,
>> when the cardinality of parameters changes dramatically, or
>> when new ANALYZE statistics are available
> Wouldn't it also make sense to flush a cached query plan when after
> execution it is determined that one or more assumptions that the cached
> query plan was based on was found to be off?
Not unless you do something that would cause the planner to make
different choices next time. (Such as changing the ANALYZE statistics,
perhaps.) The TODO item is OK as stated, it's just talking about
mechanism and not the things that might trigger the mechanism.
regards, tom lane
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