Pavel Pereslegin created IGNITE-27765:
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Summary: Sql. Support batching in CorrelatedNestedLoopJoinNode
Key: IGNITE-27765
URL: https://issues.apache.org/jira/browse/IGNITE-27765
Project: Ignite
Issue Type: Improvement
Components: sql ai3
Reporter: Pavel Pereslegin
As for now, a SharedState class for storing correlates in execution context and
is used by CorrelatedNestedLoopJoinNode (CNLJN) execution node.
Seems, CorrelatedNestedLoopJoinNode was designed to use batching for correlates
variables, to transfer many rows at a time, but implemented in wrong way, and
this just don't work.
We should fix the SharedState class to make batching possible, by allowing set
multiple rows for the same correlate id.
Most likely, we must keep correlates hierarchy order to preserve CNLJN
collation. Correlate id number doesn't have this guarantee) in case of more
than one correlate.
It may turn out that passing batches for parent correlates is useless, because
we can spool only child batch at a time to preserve the collation.
Thus, SharedState maybe split or changed it's structure, to separate
correlates, which where received from parent fragment, and current correlates
to be passed to child fragment.
Let's improve SharedState class structure to support batching, by allowing
multiple rows for same correlate and resolve ordering issue (if it exists).
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