Some refactoring:
Consolidate expression which decides whether GROUP BY/HAVING are pushed down
Rename early pullUpIntermediateRows to hasNonDistributableAggregates
Create WorkerColumnName to handle formatting WORKER_COLUMN_FORMAT
Ignore NULL StringInfo pointers to SafeToPushdownWindowFunction
Fix bug where SubqueryPushdownMultiNodeTree mutates supplied Query,
SafeToPushdownWindowFunction requires the original query as it relies on rtable
We can now support more complex count distinct operations by
pulling necessary columns to coordinator and evalutating the
aggreage at coordinator.
It supports broad range of expression with the restriction that
the expression must contain a column.
This commit doesn't change any of the logic at all.
Instead, the goal is to:
* Get rid of any code duplication
* Incremental changes to the optimizer made it slightly hard
to follow the code, improve that and make it easier to
implement new features
* Simplify the code by moving each part of query processing (e.g.,
DISTINCT, LIMIT etc) into its own function
* Make the interaction between each part of the query more
obvious (e.g., How DISTINCT affects LIMIT etc)
Before this commit, we had a divergence among
the creation of master/worker extended op nodes.
This commit moves the related parts into a single place
and allows the creation of master/extended op nodes to
share a common data structure.
SaitTalhaNisanci
Philip Dubé
Marco Slot
Jelte Fennema
Murat Tuncer
Onder Kalaci