[jira] [Created] (CALCITE-2883) HepPlanner subprogram may loop till getting out of memory

["Jesus Camacho Rodriguez (JIRA)" <ji...@apache.org>]

Jesus Camacho Rodriguez created CALCITE-2883:
------------------------------------------------

             Summary: HepPlanner subprogram may loop till getting out of memory
                 Key: CALCITE-2883
                 URL: https://issues.apache.org/jira/browse/CALCITE-2883
             Project: Calcite
          Issue Type: Bug
            Reporter: Jesus Camacho Rodriguez
            Assignee: Jesus Camacho Rodriguez


Consider the following two hep programs.

Program 1:
{code}
final HepProgramBuilder programBuilder = new HepProgramBuilder();
programBuilder.addMatchOrder(HepMatchOrder.BOTTOM_UP);
programBuilder.addRuleInstance(JoinToMultiJoinRule.INSTANCE);
programBuilder.addRuleInstance(LoptOptimizeJoinRule.INSTANCE);
final HepProgram program = programBuilder.build();
{code}

Program 2:
{code}
final HepProgramBuilder programBuilder = new HepProgramBuilder();
final HepProgramBuilder subprogramBuilder = new HepProgramBuilder();
subprogramBuilder.addMatchOrder(HepMatchOrder.BOTTOM_UP);
subprogramBuilder.addRuleInstance(JoinToMultiJoinRule.INSTANCE);
subprogramBuilder.addRuleInstance(LoptOptimizeJoinRule.INSTANCE);
programBuilder.addSubprogram(subprogramBuilder.build());
final HepProgram program = programBuilder.build();
{code}

I would expect both programs to behave similarly. However, program 2 will loop indefinitely. The reason is that {{HepPlanner}} subprogram execution loops if subprogram generates any new expression.
https://github.com/apache/calcite/blob/master/core/src/main/java/org/apache/calcite/plan/hep/HepPlanner.java#L339
This does not seem right since planner can control exiting the program (and thus, subprogram) depending on its own internal state and configuration properties, e.g., match limit.



--
This message was sent by Atlassian JIRA
(v7.6.3#76005)