[jira] [Created] (HIVE-21778) CBO: "Struct is not null" gets evaluated as `nullable` always causing pushdown miss in the query

["Rajesh Balamohan (JIRA)" <ji...@apache.org>]

Rajesh Balamohan created HIVE-21778:
---------------------------------------

             Summary: CBO: "Struct is not null" gets evaluated as `nullable` always causing pushdown miss in the query
                 Key: HIVE-21778
                 URL: https://issues.apache.org/jira/browse/HIVE-21778
             Project: Hive
          Issue Type: Bug
          Components: CBO
    Affects Versions: 2.3.5
            Reporter: Rajesh Balamohan



{noformat}
drop table if exists test_struct;
CREATE external TABLE test_struct
(
  f1 string,
  demo_struct struct<f1:string, f2:string, f3:string>,
  datestr string
);

set hive.cbo.enable=true;
explain select * from etltmp.test_struct where datestr='2019-01-01' and demo_struct is not null;



STAGE PLANS:
  Stage: Stage-0
    Fetch Operator
      limit: -1
      Processor Tree:
        TableScan
          alias: test_struct
          filterExpr: (datestr = '2019-01-01') (type: boolean) <----- Note that demo_struct filter is not added here
          Filter Operator
            predicate: (datestr = '2019-01-01') (type: boolean)
            Select Operator
              expressions: f1 (type: string), demo_struct (type: struct<f1:string,f2:string,f3:string>), '2019-01-01' (type: string)
              outputColumnNames: _col0, _col1, _col2
              ListSink


set hive.cbo.enable=false;
explain select * from etltmp.test_struct where datestr='2019-01-01' and demo_struct is not null;


STAGE PLANS:
  Stage: Stage-0
    Fetch Operator
      limit: -1
      Processor Tree:
        TableScan
          alias: test_struct
          filterExpr: ((datestr = '2019-01-01') and demo_struct is not null) (type: boolean) <----- Note that demo_struct filter is added when CBO is turned off
          Filter Operator
            predicate: ((datestr = '2019-01-01') and demo_struct is not null) (type: boolean)
            Select Operator
              expressions: f1 (type: string), demo_struct (type: struct<f1:string,f2:string,f3:string>), '2019-01-01' (type: string)
              outputColumnNames: _col0, _col1, _col2
              ListSink

{noformat}

In CalcitePlanner::genFilterRelNode, the following code misses to evaluate this filter. 
{noformat}
RexNode factoredFilterExpr = RexUtil
          .pullFactors(cluster.getRexBuilder(), convertedFilterExpr);
{noformat}

Note that even if we add `demo_struct.f1` it would end up pushing the filter correctly. Suspecting {code}RexCall::isAlwaysTrue{code} is evaluating to true in this case.



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