Re: How long should it take to insert 200,000 records? - Mailing list pgsql-performance

From Scott Marlowe
Subject Re: How long should it take to insert 200,000 records?
Date
Msg-id 1170778484.5451.97.camel@state.g2switchworks.com
Whole thread Raw
In response to How long should it take to insert 200,000 records?  ("Karen Hill" <karen_hill22@yahoo.com>)
Responses Re: How long should it take to insert 200,000 records?  ("Merlin Moncure" <mmoncure@gmail.com>)
List pgsql-performance
On Mon, 2007-02-05 at 18:35, Karen Hill wrote:
> I have a pl/pgsql function that is inserting 200,000 records for
> testing purposes.  What is the expected time frame for this operation
> on a pc with 1/2 a gig of ram and a 7200 RPM disk?   The processor is
> a 2ghz cpu.  So far I've been sitting here for about 2 million ms
> waiting for it to complete, and I'm not sure how many inserts postgres
> is doing per second.

That really depends.  Doing 200,000 inserts as individual transactions
will be fairly slow.  Since PostgreSQL generally runs in autocommit
mode, this means that if you didn't expressly begin a transaction, you
are in fact inserting each row as a transaction.  i.e. this:

for (i=0;i<200000;i++){
    insert into table abc values ('test',123);
}

Is functionally equivalent to:

for (i=0;i<200000;i++){
    begin;
    insert into table abc values ('test',123);
    commit;
}

However, you can add begin / end pairs outside the loop like this:

begin;
for (i=0;i<200000;i++){
    insert into table abc values ('test',123);
}
commit;

and it should run much faster.

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