Re: Postgres Performance Tuning

On Apr 5, 2011, at 9:33 AM, Adarsh Sharma wrote:

> Now I have to start more queries on Database Server and issue new connections after some time. Why the cached memory
isnot freed. 

It's freed on-demand.

> Flushing the cache memory is needed & how it could use so much if I set

Why would forced flushing be needed? And why would it be useful? It is not.

> effective_cache_size = 4096 MB.

Watch the "cached" field of free's output and set effective_cache_size to that amount (given that your server is
runningpostgres only, has no major other tasks) 

> I think if i issue some new select queries on large set of data, it will use Swap Memory & degrades Performance.

Have you ever tried that? Will not.

> Please correct if I'm wrong.

You seem to know very little about Unix/Linux memory usage and how to interpret the tools' output.
Please read some (very basic) documentation for sysadmins regarding these subjects.
It will help you a lot to understand how things work.

--
Akos Gabriel
General Manager
Liferay Hungary Ltd.
Liferay Hungary Symposium, May 26, 2011 | Register today: http://www.liferay.com/hungary2011