Same sql statement gets by first run an execution-plan after the second execution another much bette
Hello,
we upgrade our 10.2.0.4 Database to 11.2.0.3 (O.S.: IBM AIX 5.3)
After the upgrade, by many SQL Statement we get following behavior:
1. First execution (a badly explain-plan) Elapsed-Time= 100 min
2. Second execution we get a much better explain-plan than the first one. Elapsed-Time = 10 min
3. All others executions worked with the execution-plan generated by the second run. Elapsed-Time = 1 min
we upgrade our 10.2.0.4 Database to 11.2.0.3 (O.S.: IBM AIX 5.3)
After the upgrade, by many SQL Statement we get following behavior:
1. First execution (a badly explain-plan) Elapsed-Time= 100 min
2. Second execution we get a much better explain-plan than the first one. Elapsed-Time = 10 min
3. All others executions worked with the execution-plan generated by the second run. Elapsed-Time = 1 min
On 10g we get by every run the same execution-plan. Why ist the Optimizer getting smarter by the second execution of the exactly same sql statement? We are using constant, NO Bind Variables.
Instance parameters optimizer_% wasn't changed, all with default 11.2.0.3 Values.
Any Ideas,
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