mysql connections

cert-eh-fiable · Post by **cert-eh-fiable** » Mon Sep 21, 2009 6:55 pm

I'm trying to figure out if anywhere in the cacti setup you have the option to choose persistent connections to mysql or if this is even an option? I don't see that it is but thought I'd ask the more knowledgeable.

I'm running 0.8.7.e and what I'm see is that cacti is making a connection to the mysql database for each graph lookup when I view the graphs produced by cacti on the graphs page.

Now I don't have a problem with this but instead of terminating like they should they sleep on mysql but never get reused as further graph requests open new connections. I've got only a limited number of resources and trying to make cacti fit into those is becoming impossible.

Now I know I can change the mysql timeout and interactive timeout settings but I have a need for apache to keep a connection open and not get reset by limiting my mysql timeout. So I really can't use that option.

Does anyone know or have had this problem that's fixed the mysql connection issue with cacti?

Thanks.

~cert

Post by **TheWitness** » Thu Sep 24, 2009 7:41 am

In my.cnf [mysqld] section add:

Code: Select all

max_connections = 300

Restart MySQL

TheWitness

cert-eh-fiable · Post by **cert-eh-fiable** » Thu Sep 24, 2009 9:18 pm

Don't I wish everything was this easy. <chuckles>

If so I'd put in my.cnf

Code: Select all

upgrade_memory = 24G

Like I said I'm working within the resources I have with my hardware. Adding connections means I have to take memory away from other mysql tasks namely caching to memory which forces more disk writes so I trade connections for performance. Optimally cacti wouldn't flood mysql with needless connections and close them properly when they are done being used.

Thanks for the input, it is appreciated.

~cert

Post by **TheWitness** » Thu Sep 24, 2009 9:36 pm

Cacti closes connections. It might have something to do with the Apache. Not sure. It may have something to do with the persistent connections and Adodb. Maybe we need to check for Adodb bugs and do an upgrade if necessary.

TheWitness

fuhrysteve · Post by **fuhrysteve** » Mon Oct 19, 2009 9:55 am

I'm also getting a lot of open connections; I attached a screenshot to give a better idea. I'm not sure whether it's the poller or cacti-spine that's opening these connections (I'll investigate further), but it shouldn't be apache, as these connections keep getting spawned even if no one is using the web interface.

fuhrysteve · Post by **fuhrysteve** » Mon Oct 19, 2009 10:22 am

Changed PConnect to Connect in lib/database.php per the advice of TheWitness here: http://forums.cacti.net/about20493.html

It seems to be closing connections now.. but it'll take awhile to be sure. Will post back if this doesn't work.

mysql connections

mysql connections

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