JoinOrderStrategy
Related Docs:
object JoinOrderStrategy
| package sources
Returns true if expr can be evaluated using only the output of plan.
Returns true if expr can be evaluated using only the output of plan. This method
can be used to determine when it is acceptable to move expression evaluation within a query
plan.
For example consider a join between two relations R(a, b) and S(c, d).
- canEvaluate(EqualTo(a,b), R) returns true
- canEvaluate(EqualTo(a,c), R) returns false
- canEvaluate(Literal(1), R) returns true as literals CAN be evaluated on any plan
Returns true iff expr could be evaluated as a condition within join.
Returns true iff expr could be evaluated as a condition within join.
Trait to apply different join order policies like Replicates with filters first, then largest colocated group, and finally non-colocated with filters, if any.
One can change the ordering policies as part of query hints and later can be admin provided externally against a regex based query pattern.
e.g. select * from /*+ joinOrder(replicates+filters, non-colocated+filters) */ table1, table2 where ....
note: I think this should be at the query level instead of per select scope i.e. something like /*+ joinOrder(replicates+filters, non-colocated+filters) */ select * from tab1, (select xx from tab2, tab3 where ... ), tab4 where ...