Re: Slow set-returning functions - Mailing list pgsql-performance

From Tom Lane
Subject Re: Slow set-returning functions
Date
Msg-id 10405.1200853835@sss.pgh.pa.us
Whole thread Raw
In response to Re: Slow set-returning functions  ("Merlin Moncure" <mmoncure@gmail.com>)
Responses Re: Slow set-returning functions  (Dean Rasheed <dean_rasheed@hotmail.com>)
List pgsql-performance
"Merlin Moncure" <mmoncure@gmail.com> writes:
> prepared statements have the same problem.  IIRC the planner assumes
> 10%, which will often drop to a seqscan or a bitmap index scan.  Some
> years back I argued (unsuccessfully) to have the planner guess 100
> rows or something like that.  Ideally, I think it would generate the
> plan from the value passed into the first invocation of the function.

I believe it's the case that that will happen now in the same contexts
where the planner uses the first value of any other parameter (ie,
unnamed statements in the extended-query protocol).

            regards, tom lane

pgsql-performance by date:

Previous
From: Dean Rasheed
Date:
Subject: Re: Slow set-returning functions
Next
From: Adrian Moisey
Date:
Subject: Re: strange pauses