[jira] [Created] (CALCITE-5561) HepProgramBuilder.addSubprogram does not add a subprogram

["Jonathan A Sternberg (Jira)" <ji...@apache.org>]

Jonathan A Sternberg created CALCITE-5561:
---------------------------------------------

             Summary: HepProgramBuilder.addSubprogram does not add a subprogram
                 Key: CALCITE-5561
                 URL: https://issues.apache.org/jira/browse/CALCITE-5561
             Project: Calcite
          Issue Type: Bug
          Components: core
    Affects Versions: 1.33.0
            Reporter: Jonathan A Sternberg
         Attachments: hepsubquery.patch

It appears that the {{addSubprogram}} method in {{HepProgramBuilder}} might not be working as advertised. The [javadoc|https://calcite.apache.org/javadocAggregate/org/apache/calcite/plan/hep/HepProgramBuilder.html#addSubprogram(org.apache.calcite.plan.hep.HepProgram)] indicates that the subprogram will be run repeatedly until the fix point is reached or no changes have been made (whichever comes first).

On the other hand, when using this method and running the associated {{{}HepProgram{}}}, the subprogram doesn't appear to run repeatedly.

When I run the unit test for testing this and I try to set a breakpoint in {{{}executeSubquery{}}}, that line of code is never hit. I believe the error might be here: [https://github.com/apache/calcite/blob/ee9b80b0b68d442991dfaa142722e3488ec73e79/core/src/main/java/org/apache/calcite/plan/hep/HepInstruction.java#L273]

I think that this line is calling prepare for the subprogram itself and returning the state for the underlying program rather than returning the state associated with the subprogram. This causes it to never run [this code|https://github.com/apache/calcite/blob/ee9b80b0b68d442991dfaa142722e3488ec73e79/core/src/main/java/org/apache/calcite/plan/hep/HepInstruction.java#L290] (which internally runs the program repeatedly).

I've attached a diff that seems to fix it for me, but I'm not sure how I would write an appropriate unit test for it. I can submit it as a PR and get help with writing the test.



--
This message was sent by Atlassian Jira
(v8.20.10#820010)