Re: Collect frequency statistics for arrays
| От | Tom Lane |
|---|---|
| Тема | Re: Collect frequency statistics for arrays |
| Дата | |
| Msg-id | 26664.1330557044@sss.pgh.pa.us обсуждение |
| Ответ на | Re: Collect frequency statistics for arrays (Nathan Boley <npboley@gmail.com>) |
| Ответы |
Re: Collect frequency statistics for arrays
|
| Список | pgsql-hackers |
Nathan Boley <npboley@gmail.com> writes:
> On Wed, Feb 29, 2012 at 2:43 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Nathan Boley <npboley@gmail.com> writes:
>>> If I understand you're suggestion, queries of the form
>>> SELECT * FROM rel
>>> WHERE ARRAY[ 1,2,3,4 ] <= x
>>> � � �AND x <=ARRAY[ 1, 2, 3, 1000];
>>> would no longer use an index. Is that correct?
>> No, just that we'd no longer have statistics relevant to that, and would
>> have to fall back on default selectivity assumptions.
> Which, currently, would mean queries of that form would typically use
> a table scan, right?
No, it doesn't.
> What about MCV's? Will those be removed as well?
Sure. Those seem even less useful.
regards, tom lane
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