after check out the wiki page Maciek mentioned, turns out that heavy connection also burden the disk hardly.
looks like I am in the vicious circle:
1, slow query cause connection blocked so the client request more connection.
2, more connection cause high disk io and make even the simplest query slow and block.
I guess I should optimized those queries first...
On Thu, Jul 12, 2012 at 10:20 AM, Craig Ringer
<ringerc@ringerc.id.au> wrote:
On 07/12/2012 08:47 AM, Yan Chunlu wrote:
Really sorry for the lack of information
I shouldn't have grumped like that either, sorry about that.
I didn't mention the connections number because I don't think my app is that busy, and the large number connections was caused by slow queries.
Yep - assumptions are a killer like that.
Now you know to watch your system load with iostat, vmstat, top, etc and to monitor your overall load.
--
Craig Ringer