Re: High Disk write and space taken by PostgreSQL

Hi Ramesh,

Are you able to provide a table schema? Were you using MyISAM or InnoDB
on MySQL?

If you back up the database & restore clean, what is the size comparison
of the database filed on the restored copy to the existing one? It may
be full of empty tuples. Is there any period where you could try a full
vacuum?

What are your indexes? Is the size in the indexes or the database tables?

At the current rate of insertion, that table is going to get very large
very quickly. Do you have anything deleting the rows afterwards? I
have no experience with databases past 50M rows, so my questions are
just so you can line up the right info for when the real experts get
online :-)

Regards, David

On 16/08/12 11:23, J Ramesh Kumar wrote:
>
> Hi,
>
> My application has high data intensive operations (high number of
> inserts 1500 per sec.). I switched my application from MySQL to
> PostgreSQL. When I take performance comparison report between mysql
> and pgsql, I found that, there are huge difference in disk writes and
> disk space taken. Below stats shows the difference between MySQL and
> PostgreSQL.
>
>
> *MySQL* *PostgreSQL*
> Inserts Per Second* 1500 1500
> Updates Per Second* 6.5 6.5
> Disk Write Per Second* 0.9 MB 6.2 MB
> Database Size Increased Per day* 13 GB 36 GB
>
>
> * approx values
>
> Why this huge difference in disk writes and disk space utilization?
> How can I reduce the disk write and space ? Kindly help me. Please let
> me know, if you require any other information(such as postgres.conf).
>
> Thanks,
> Ramesh