Re: High Disk write and space taken by PostgreSQL - Mailing list pgsql-performance

From David Barton
Subject Re: High Disk write and space taken by PostgreSQL
Date
Msg-id 502C6AD5.4070407@oneit.com.au
Whole thread Raw
In response to High Disk write and space taken by PostgreSQL  (J Ramesh Kumar <rameshj1977@gmail.com>)
Responses Re: High Disk write and space taken by PostgreSQL
List pgsql-performance
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.


MySQLPostgreSQL
Inserts Per Second*15001500
Updates Per Second*6.56.5
Disk Write Per Second*0.9 MB6.2 MB
Database Size Increased Per day* 13 GB36 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

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