Hi team
Optimizer max permutations and search limit are set to 3.5 million and 10 respectively.The parameter instruct optimizer to evaluate up to 3.5 million permutations for max 10 table joins
I have query with 9 tables joined.
How many combinations will optimizer perform to find best join order? within parameter bounds
Please share me the answer . Is it 9! or 10! or 3.5 million or something else.
Mathematically, the total number of permutations for joining 9 tables would be 9! or 362880.
However, the parameters - optimizer_max_permutations and optimizer_search_limit are undocumented (deprecated) in Oracle version 10g and higher.
Oracle hasn't mentioned or documented the algorithm it uses to derive the value, so I wouldn't rely too much on that number.
Besides, since they are deprecated: (a) use them at your own risk and (b) Oracle will not provide any support in case you run into problems using them.