Re: Performance Low Using the Prepare and Execute - Mailing list pgsql-general

From Neil Conway
Subject Re: Performance Low Using the Prepare and Execute
Date
Msg-id 1136693070.9135.19.camel@localhost.localdomain
Whole thread Raw
In response to Performance Low Using the Prepare and Execute  (Marcos José Setim <mjs_ops@gmx.net>)
List pgsql-general
On Sat, 2006-01-07 at 20:38 +0000, Marcos José Setim wrote:
> I want to use the Prepare and Execute resources of PostgreSQL to
> increment the performance of my SQL's.

> $sSQL = 'INSERT INTO teste (nome) VALUES( ? )';
>
> $oDB->Prepare( $sSQL );

The PREPARE documentation states:[1]

        Prepared statements have the largest performance advantage when
        a single session is being used to execute a large number of
        similar statements. The performance difference will be
        particularly significant if the statements are complex to plan
        or rewrite, for example, if the query involves a join of many
        tables or requires the application of several rules. If the
        statement is relatively simple to plan and rewrite but
        relatively expensive to execute, the performance advantage of
        prepared statements will be less noticeable.

Since an INSERT ... VALUES without a subselect or any applicable rules
requires very little parsing, planning, or rewriting time,
PREPARE/EXECUTE is unlikely to improve performance.

-Neil

[1] http://developer.postgresql.org/docs/postgres/sql-prepare.html


pgsql-general by date:

Previous
From: Neil Conway
Date:
Subject: Re: Create one prepared function
Next
From: Postgres User
Date:
Subject: Installing Postgres 8.1 on Windows Server 2003 R2