Re: *_collapse_limit, geqo_threshold - Mailing list pgsql-hackers

From Kevin Grittner
Subject Re: *_collapse_limit, geqo_threshold
Date
Msg-id 4A573B4402000025000286A7@gw.wicourts.gov
Whole thread Raw
In response to Re: *_collapse_limit, geqo_threshold  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: *_collapse_limit, geqo_threshold  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
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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