[CALCITE-4936] Generalize FilterCalcMergeRule/ProjectCalcMergeRule to accept any Filter/Project/Calc operator

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.28.0
• Fix Version/s: 1.31.0
• Component/s: core
• Labels: pull-request-available
• Assignee: Unassigned
• Reporter: Maksim Gramin
• Created: 11/Dec/21 22:28
• Updated: 03/Aug/22 16:21
• Resolved: 11/Apr/22 09:16

Description

I noticed that rules ProjectCalcMergeRule and FilterCalcMergeRule strictly dependent on LogicalCalc class (e.g. casting call.rel to LogicalCalc, using LogicalCalc.create method and etc). I suggest making them more generalized (like CalcMergeRule) and use only Project, Filter and Calc interfaces, which will expand the range of their applying.

Concrete:

1. In FilterCalcMergeRule get rid of casting to LogicalCalc and LogicalFilter:

@Override public void onMatch(RelOptRuleCall call) {
  final Filter filter = call.rel(0);
  final Calc calc = call.rel(1);

 

2. In FilterCalcMergeRule and FilterCalcMergeRule replace LogicalCalc.create with calc.copy:

final Calc newCalc = calc.copy(calc.getTraitSet(), calc.getInput(),
mergedProgram);

 

3. In ProjectCalcMergeRule replace the code:

if (RexOver.containsOver(program)) {
  LogicalCalc projectAsCalc = LogicalCalc.create(calc, program);
  call.transformTo(projectAsCalc);
  return;
}

with a simple one:

if (RexOver.containsOver(program)) {
  return;
}

because special rule ProjectToCalcRule convert LogicalProject to LogicalCalc.

Issue Links

• links to: GitHub Pull Request #2646