Database Statistics or bechmark tools

I have to monitor database statistic for postgresql.In future it may change.So the tool which support multiple database server would be better. The statistics are like : 1. Query execution time. 2. Number of queries that are executed per sec. 3. Number of queries are still in execution. 4. Ram usage of the query utlitizat开发者_运维百科ion.

If any module available to integrate in my applications??

A number of useful tools and methods are documented in the wiki:

http://wiki.postgresql.org/wiki/Logging_Difficult_Queries