Scott hi, i calculate all of my jdbc pool size. Maximum is 300 connections from components wich use jdbc. I don't think that this is a good idea use pgbouncer, because our application using spring framework which using jdbc and prepared statement. I try to talk with our developer about disabling prepared statement in this framework, they don't want do this. Thats why i will try to upgrade HW and buy CPU with more core as you say based on formula 3-4xcore. But most of this connection is idle. This is a web based app not a datawarehouse, thats why all this connection is lightwear.
About my db freeze i set this kernel parameter:echo 1048576 > /proc/sys/vm/min_free_kbytes
echo 80 > /proc/sys/vm/vfs_cache_pressure
2013/11/6 Scott Marlowe <scott.marlowe@xxxxxxxxx>
Also also, the definitive page for postgres and dirty pages etc is here:
http://www.westnet.com/~gsmith/content/linux-pdflush.htm
Not sure if it's out of date with more modern kernels. Maybe Greg will chime in.
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С уважением Селявка Евгений