we've recently moved one of our production databases from a 8.3 based server to a 9.2 installation. Our usage patterns remained the same, however, we noticed that the swap space in the server started to decrease with time.
We have roughly 16 connections to this database in an almost constant basis, pooled by a java connection pooler on the app side. This connections never expire (nor did they do with the 8.3 db). However, as you can see on this memory usage chart http://i.imgur.com/2sRRj1J.png it shows a rolleccoaster like pattern. When we restart our application, the connections are closed and the memory is freed.
Our work_mem is 2MB, so it does not warrant the large memory allocation. Also I am completely sure that this is the pg connection process that's eating up the memory.
Is it the process on the client side or the server side that is using the memory?
How many tables are in the database? Every additional table touched will pull in some more metadata, so over the course of a long lived connection in the pool, it could grow a lot if you have a lot of tables.
