sql tuning on X$ table
- From: "Eagle Fan" <eagle.f@xxxxxxxxx>
- To: oracle-l@xxxxxxxxxxxxx
- Date: Thu, 30 Nov 2006 10:31:50 +0800
hi:
We have a monitoring tool to monitor database performance.
It run the following sql every few seconds and it cost a lot of CPU times.
About 20% of total CPU time.
select kslltnum latch#,sum(kslltwgt) gets,sum(kslltwff) misses,
sum(kslltwsl) sleeps from x$ksllt group by
kslltnum;
The sql is used to collect latch statistics, latch#, gets, misses, sleeps
and then get the top heavy latch contentions.
I have no idea how to tune this sql. It's on x$ table.
I have read kyle's presentation about direct SGA access and I think it may
help the sql.
Does anyone have experiences of using direct SGA access on production
system?
Any risks? How many performance gains?
Thanks
--
Eagle Fan
Oracle DBA
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