Re: Postgres insert performance and storage requirement compared to Oracle - Mailing list pgsql-performance

From Divakar Singh
Subject Re: Postgres insert performance and storage requirement compared to Oracle
Date
Msg-id 604758.88084.qm@web65414.mail.ac4.yahoo.com
Whole thread Raw
In response to Re: Postgres insert performance and storage requirement compared to Oracle  (Alex Hunsaker <badalex@gmail.com>)
Responses Re: Postgres insert performance and storage requirement compared to Oracle
Re: Postgres insert performance and storage requirement compared to Oracle
List pgsql-performance
So another question pops up: What method in PostgreSQL does the stored proc use when I issue multiple insert (for loop for 100 thousand records) in the stored proc?
It takes half the time compared to the consecutive "insert" using libpq.
In the backend, does it use COPY or prepared statement? or something else?
 
Best Regards,
Divakar



From: Alex Hunsaker <badalex@gmail.com>
To: Divakar Singh <dpsmails@yahoo.com>
Cc: Steve Singer <ssinger@ca.afilias.info>; jd@commandprompt.com; pgsql-performance@postgresql.org
Sent: Thu, October 28, 2010 1:15:06 AM
Subject: Re: [PERFORM] Postgres insert performance and storage requirement compared to Oracle

On Wed, Oct 27, 2010 at 08:00, Divakar Singh <dpsmails@yahoo.com> wrote:
> I am attaching my code below.
> Is any optimization possible in this?
> Do prepared statements help in cutting down the insert time to half for this
> kind of inserts?

In half? not for me.  Optimization possible? Sure, using the code you
pasted (time ./a.out 100000 <method>):
PQexec: 41s
PQexecPrepared: 36s
1 insert statement: 7s
COPY: 1s
psql: 256ms

Basically the above echoes the suggestions of others, use COPY if you can.

Find the source for the above attached.  Its just a very quick
modified version of what you posted. [ disclaimer the additions I
added are almost certainly missing some required error checking... ]

[ psql is fast because the insert is really dumb: insert into aaaa (a,
b, c, d, e, f, g, h, j, k, l, m, n, p) select 1, 'asdf', 'asdf',
'asdf', 'asdf', 'asdf', 'asdf', 'asdf', 'asdf', 'asdf', 'asdf',
'asdf', 'asdf', 'asdf' from generate_series(1, 100000); ]

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