A
Alon Blich
Guest
changing the join order and indexes might be 20% of the possible optimizations but they account for 80% or more of the cases. there is alot more to changing the buffers join order and also finding all the possible index brackets. when changing the join order the conditions need to be divided differently between the joins and preferably pushed up. this might be simple if there are only and conditions but is far more complicated with complicated or and and conditions. and to discover all the different index brackets the where condition might need to be refactored (and initially simplifed). i also believe that rule based optimizer can be very useful but the join order and indexes cannot stay fixed for every condition. imho no other performance improvement comes close.
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