Re: Trim performance on 9.5 - Mailing list pgsql-general

From vinny
Subject Re: Trim performance on 9.5
Date
Msg-id b03e0eaadb08647c104d4a378c328e4d@xs4all.nl
Whole thread Raw
In response to Trim performance on 9.5  (William Ivanski <william.ivanski@gmail.com>)
Responses Re: Trim performance on 9.5  (William Ivanski <william.ivanski@gmail.com>)
List pgsql-general
On 2016-11-18 15:06, William Ivanski wrote:
> Hi,
>
> I recently did major improvements on perfomance on our routines by
> simply removing the call for trim functions on specific bottlenecks.
> Please see images attached for a simple example.
>
> I'm using PostgreSQL version 9.5.5-1.pgdg80+1 on Debian 8.6. Someone
> knows if it's a bug on trim function? Thanks in advance.
>
> --
>
> William Ivanski

Did you run EXPLAIN on these queries?

I'm guessing that you have an index on the field, but not on
TRIM(field),
which would mean that the database is forced to seqscan to fetch every
row value, trim it and then compare it.


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