[CALCITE-3784] RexCall toString digest gives OOM while huge expression is evaluated

• Type: Bug
• Status: Open
• Priority: Critical
• Resolution: Unresolved
• Component/s: core
• Assignee: Unassigned
• Reporter: Ravi Kapoor
• Created: 11/Feb/20 11:31
• Updated: 13/Feb/20 10:29

Description

I have some complex query which has tens of thousands of rex expressions and this expression is used in filter expression in the query.

On creating a filter below code gets called:

public RelBuilder filter(Iterable<CorrelationId> variablesSet,
  Iterable<? extends RexNode> predicates) {

  final RexNode simplifiedPredicates =
  simplifier.simplifyFilterPredicates(predicates);
  if (simplifiedPredicates == null) {
    return empty();
 }

RexSimplify further adds the rexnode in the Set<RexNode> calling hashcode() internally which calls toString()

Is there any way to avoid this computeDigest Call which creates complex string object and blows up the  RAM about 10GB?