Обсуждение: Performance Improvement in SQL

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Performance Improvement in SQL

От
Lucas Souza Cruz
Дата:
Hi, my name is Lucas Souza and i live in Goi=C3=A2nia, Brazil.
Recently, i had a problem with an SQL due to delay.

The part of the SQL that was slow is: ' WHERE idprod =3D 123456 '.

In this line, the execution was of fifteen seconds.

And i try this: ' WHERE CASE WHEN idprod =3D 123456 THEN TRUE ELSE FALSE EN=
D
=3D TRUE '.

Now, the execution was half of one second.


I sending this e-mail because i believe that the PostgreSQL Community can
improvement the perfomance of database

If this solution exists, sorry for this e-mail.

And sorry too for my english.

Thanks.
Lucas de Souza Cruz

Re: Performance Improvement in SQL

От
"David G. Johnston"
Дата:
On Thu, Mar 10, 2016 at 7:44 AM, Lucas Souza Cruz <souzacruz001@gmail.com>
wrote:

> Hi, my name is Lucas Souza and i live in Goi=C3=A2nia, Brazil.
> Recently, i had a problem with an SQL due to delay.
>
> The part of the SQL that was slow is: ' WHERE idprod =3D 123456 '.
>
> In this line, the execution was of fifteen seconds.
>
> And i try this: ' WHERE CASE WHEN idprod =3D 123456 THEN TRUE ELSE FALSE =
END
> =3D TRUE '.
>
> Now, the execution was half of one second.
>
>
> I sending this e-mail because i believe that the PostgreSQL Community can
> improvement the perfomance of database
>
> If this solution exists, sorry for this e-mail.
>
> And sorry too for my english.
>
>
=E2=80=8BThanks for the report but there isn't enough information here to d=
o
anything with - and given the nature of the complaint if there actually was
an issue that caused your described behavior I am positive we would have
heard about it.  I'm chalking it up to "solar flares at the time the first
query was run" - but if you can construct something repeatable, on a
current version of PostgreSQL (9.1-5.x=3Dmost recent point release), and sh=
ow
actual system generated evidence (namely, "explain analyze" output)

=E2=80=8Bthen maybe this report can be given attention.

And regardless you should read the following as a start for how to
formulate this kind of request:

http://www.postgresql.org/docs/current/static/bug-reporting.html
https://wiki.postgresql.org/wiki/Slow_Query_Questions

David J.
=E2=80=8B