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Re: Sudden slow down and spike in system CPU causes max_connections to get exhausted

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On 1/6/2014 5:06 PM, Anand Kumar, Karthik wrote:

We run postgres 9.1.11, on Centos 6.3, and an ext2 filesystem

please tell me thats a typo, and you're using ext4, or at least ext3.

We do typically have a lot of idle connections (1500 connections total, over a 1000 idle at any given time). We're in the midst of installing pgbouncer to try and mitigate the problem, but that still doesn't address the root cause.


having 500 not-idle connections is disturbing. depending on the complexities of those 500 active queries, you could be using 500 or 1000 or more times your work_mem setting in temporary buffers on top of your other memory allocations. thats also going to use a LOT of file handles in your kernel. and having 500 active queries competing for your CPU cores, ouch.

I bet you're running out of memory during these busy peaks and going very page-swap bound.


--
john r pierce                                      37N 122W
somewhere on the middle of the left coast



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