Re: *_collapse_limit, geqo_threshold

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От Kevin Grittner
Тема Re: *_collapse_limit, geqo_threshold
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Msg-id 4A573B4402000025000286A7@gw.wicourts.gov
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Ответ на Re: *_collapse_limit, geqo_threshold  (Tom Lane <tgl@sss.pgh.pa.us>)
Ответы Re: *_collapse_limit, geqo_threshold  (Tom Lane <tgl@sss.pgh.pa.us>)
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Tom Lane <tgl@sss.pgh.pa.us> wrote: 
> "Kevin Grittner" <Kevin.Grittner@wicourts.gov> writes:
>> treat parentheses around JOIN operations as optimizer hints.
> 
> That's a *truly* horrid idea, as sometimes you need them simply to
> get the precedence correct.
You do, but it's been pretty rare in my experience, and we're
considering alternatives which give a lot less flexibility that this.
The *truly* awful thing about the SAP-DB implementation is that it
wasn't optional -- parentheses in this part of a query always limited
optimizer options; I sure wouldn't want to go there again.  I thought
we were talking about options for what to do when an enable_* setting
was off for diagnostic purposes....
-Kevin


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