Latch Waits
Hi,
Yesterday I started getting a lot of latch waits - onstat -u had "S" in the
1st position in the flags column. onstat -g lmx showed a lot of processes
waiting on a mutex called "global cach" I cannot find much information about
this mutex.
The question I'm asking is why would I get this situation? It has been
running fine previously. I did change BUFFERS from 1900000 to 4000000 and
RESIDENT from -1 to 0. So why would changing these two parameters cause the
mutex waits. When the change was made checkpoints went up from 1-3 seconds
every 15 minutes to 5+ seconds every 5 minutes (leaving the interval at 15
minutes meant we had checkpoints > 10 seconds)
Some onconfig parameters:
LRUS 511CLEANERS 127 (onstat -u shows some page cleaners not doing any work - no of
writes=0)
CKPTINTVL 900
LRU_MAX_DIRTY 1
LRU_MIN_DIRTY 0
RA_THRESHOLD 4
NOAGE 1
NETTYPE tlitcp,15,256,NET
onstat -u shows approx 1300 connections
Any insight into why I had the above problem would be appreciated.
Many Thanks
Colin Dawson
www.ladbrokes.com
sending to informix-list