enq: HW - contention waits
491119Apr 18 2008 — edited Oct 17 2009Greetings,
We have a production database running on RAC (4-node) (10.2.0.3 on Solaris 10) and I'm noticing a lot of waits on "enq: HW - contention". Doing a bit of researching tells me that it is related to HWM extensions (concurrent inserts). We have no control on the application so I wonder what could be done from the database end to tune this up (if anything). Here's what I see from the AWR during the time it showed up --
Top 5 Timed Events
Event Waits Time(s)Avg Wait(ms)% Total Call TimeWait Class
CPU time 7,148 43.5
enq: HW - contention 67,034 5,263 79 32.0 Configuration
SQL*Net break/reset to client 61,006 1,504 25 9.2 Application
db file sequential read 152,431 885 6 5.4 User I/O
gc cr block busy 34,315 490 14 3.0 Cluster
Any help is deeply appreciated!!
TIA,
- Ravi Gaur