Re: UDF in C slow

From: Inanc Seylan <inanc(dot)seylan(at)gmail(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Alban Hertroys <haramrae(at)gmail(dot)com>, pgsql-general(at)postgresql(dot)org
Subject: Re: UDF in C slow
Date: 2012-05-11 16:00:42
Message-ID: 4FAD37AA.9080603@gmail.com
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I'm quite new to Postgres so I don't know how to read the execution
plans. However it is obvious that the plans for the query with and
without the function are different. I added some indices to the table
roleassertions and it seems to solve this big difference in the
execution times of both queries. So I guess it was not the function that
was the problem in the end. Thanks a lot!

Inanc

On 5/11/12 5:55 PM, Tom Lane wrote:
> Inanc Seylan<inanc(dot)seylan(at)gmail(dot)com> writes:
>> It is IMMUTABLE. I attach the output of EXPLAIN both with and without
>> the simple function (returning true only) in the query.
>
> EXPLAIN ANALYZE would have been far more helpful. However, the thing
> that jumps out at me here is all the seqscans on table "symbols".
> Do you not have an index on symbols.id? If you do, perhaps there is
> a datatype-mismatch problem preventing it from being used.
>
> regards, tom lane

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