Michael Braun created CALCITE-7794:
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Summary: Reduce the work HepPlanner does per rule application
attempt
Key: CALCITE-7794
URL: https://issues.apache.org/jira/browse/CALCITE-7794
Project: Calcite
Issue Type: Improvement
Reporter: Michael Braun
HepPlanner tries every rule in a collection against every vertex, so missed
attempts
can greatly outnumber matches.
On every attempt, {{applyRule}} tests {{graph.vertexSet().contains(vertex)}}.
Both
call sites try every rule against the same vertex in a loop that only exits
early on
a match, so membership cannot change within it: 100 rules means 100 set lookups
where one would do.
On attempts that cannot match -- the large majority -- {{applyRule}} also
allocates
{{bindings}} and {{nodeChildren}} before calling {{matchOperands}}, which
rejects on
its first statement, and runs the {{ConverterRule}} and {{CommonRelSubExprRule}}
branches, traversing a vertex's parents, before the operand is tested.
Proposed: move the membership test to the two callers, which need it once per
vertex;
return early for an empty rule collection; and test the operand first in
{{applyRule}}, splitting {{matchOperands}} into a thin entry point making that
test
and a body assuming it.
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