Re: [GENERAL] Trim performance on 9.5

[Vincent Elschot]

Op 18/11/2016 om 16:58 schreef William Ivanski:
I just ran EXPLAIN ANALYZE, please see images attached. Field doesn't 
have a index.


Em sex, 18 de nov de 2016 às 12:16, vinny > escreveu:


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.

--

William Ivanski



Neither exeution times are really "fast", I'd suggest creating an index 
on the TRIM() version of the field.

Re: [GENERAL] Trim performance on 9.5

[William Ivanski]

I just ran EXPLAIN ANALYZE, please see images attached. Field doesn't have
a index.

Em sex, 18 de nov de 2016 às 12:16, vinny  escreveu:

> 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.
>
-- 

William Ivanski

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Re: [GENERAL] Trim performance on 9.5

[vinny]

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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[GENERAL] Trim performance on 9.5

[William Ivanski]

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

-- 
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To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-general