[jira] [Created] (DRILL-7557) Revise "Base" storage plugin filter-push down listerner with a builder

["Paul Rogers (Jira)" <ji...@apache.org>]

Paul Rogers created DRILL-7557:
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             Summary: Revise "Base" storage plugin filter-push down listerner with a builder
                 Key: DRILL-7557
                 URL: https://issues.apache.org/jira/browse/DRILL-7557
             Project: Apache Drill
          Issue Type: Improvement
    Affects Versions: 1.18.0
            Reporter: Paul Rogers
            Assignee: Paul Rogers
             Fix For: 1.18.0


DRILL-7458 introduces a base framework for storage plugins and includes a simplified mechanism for filter push down. Part of that mechanism includes a "listener", with the bulk of the work done in a single method:

{code:java}
Pair<GroupScan, List<RexNode>> transform(GroupScan groupScan,
      List<Pair<RexNode, RelOp>> andTerms, Pair<RexNode, DisjunctionFilterSpec> orTerm);
{code}

Reviewers correctly pointed out that this method might be a bit too complex.

The listener pattern pretty much forced the present design. To improve it, we'd want to use a different design; maybe some kind of builder which might:

* Accept the CNF and DNF terms via dedicated methods.
* Perform a processing step.
* Provide a number of methods to communicate the results, such as 1) whether a new group scan is needed, 2) any CNF terms to retain, and 3) any DNF terms to retain.




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