Hi Venky,
There can be many reasons.Below are few questions I would ask myself for
troubslehooting.
Are you able to replicate ? Good vs plan depends on the data it is querying
?
Are you using bind variables in your query? Using bind variables vs hard
coded makes any difference? Is it selecting data from partitions?What’s
your oracle version? Are you using 12c adaptive features that’s making this
change in behavior ?
For fixing, one option is to get good plan hash value and fix using
baseline.
Thanks,
Vishnu
On Wed, Jul 18, 2018 at 6:30 PM V Raman <vraman4list@xxxxxxxxx> wrote:
List
We have a SQL that is performing intermittently bad in our prod env. The
good ones take 2 to 5 mins, the bad ones run for hours we kill them. They
run fine in the non prod env. I ran an awsqrpt and based on that I see that
there are a few executions with the bad ones taking hours. Looking at the
differences in the execution plan, the good ones have lots of nested loops
in them, with the bad ones having lots of hash joins.
I am trying to figure out the cause(s). Assuming there is not much change
in the DB, the first thing that comes to mind is statistics. Can the
listers help with ideas? Thanks.
If anyone is interested is seeing the report, i can provide a link to them
by email.
Venky
