Re: sequential scan unduly favored over text search gin index - Mailing list pgsql-performance

From Tom Lane
Subject Re: sequential scan unduly favored over text search gin index
Date
Msg-id 4289.1308635599@sss.pgh.pa.us
Whole thread Raw
In response to Re: sequential scan unduly favored over text search gin index  (Sushant Sinha <sushant354@gmail.com>)
Responses Re: sequential scan unduly favored over text search gin index
List pgsql-performance
Sushant Sinha <sushant354@gmail.com> writes:
>> I guess you could poke the planner towards the bitmap scan by lowering
>> the random_page_cost (the default value is 4, I'd say lowering it to 2
>> should do the trick).

> The numbers that I gave was after setting random_page_cost = 1.0 After
> this I don't know what to do.

I think part of the issue here is that the @@ operator is expensive,
and so evaluating it once per row is expensive, but the pg_proc.procost
setting for it doesn't adequately reflect that.  You could experiment
with tweaking that setting ...

            regards, tom lane

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