Re: A Better Way? (Multi-Left Join Lookup) - Mailing list pgsql-general

From Tom Lane
Subject Re: A Better Way? (Multi-Left Join Lookup)
Date
Msg-id 29022.1342907257@sss.pgh.pa.us
Whole thread Raw
In response to Re: A Better Way? (Multi-Left Join Lookup)  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: A Better Way? (Multi-Left Join Lookup)  ("David Johnston" <polobo@yahoo.com>)
List pgsql-general
I wrote:
> "David Johnston" <polobo@yahoo.com> writes:
>> So,
>> EXPLAIN SELECT function_call(...)  -- yields a planner expectation of 1 row
>> [Whereas]
>> EXPLAIN SELECT * FROM function_call(...) -- yields a planner expectation of
>> "result_rows" which defaults to 1000

> Hm ...

>> Was this an intentional design decision to override the result_rows estimate
>> of the function if it is used in the select list?

> Not so much an intentional decision as just that nobody ever did
> anything about it.

I've now done something about that for 9.2.  I'm loath to back-patch it
into any already-stable releases, though, for fear of destabilizing
plan choices that production applications might be relying on.

            regards, tom lane

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