[jira] [Created] (DRILL-4010) In HBase reader, create child vectors for referenced HBase columns to avoid spurious schema changes

["Daniel Barclay (Drill) (JIRA)" <ji...@apache.org>]

Daniel Barclay (Drill) created DRILL-4010:
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             Summary: In HBase reader, create child vectors for referenced HBase columns to avoid spurious schema changes
                 Key: DRILL-4010
                 URL: https://issues.apache.org/jira/browse/DRILL-4010
             Project: Apache Drill
          Issue Type: Bug
          Components: Execution - Data Types, Storage - HBase
            Reporter: Daniel Barclay (Drill)


{{HBaseRecordReader}} needs to create child vectors for all referenced/requested columns.

Currently, if a fragment reads only HBase rows that don't have a particular referenced column (within a given column family), downstream code adds a dummy column of type {{NullableIntVector}} (as a child in the {{MapVector}} for the containing HBase column family).

If any other fragment reads an HBase row that _does_ contain the referenced column, that fragment's reader will create a child {{NullableVarBinaryVector}} for the referenced column.

When the data from those two fragments comes together, Drill detects a schema change, even though logically there isn't really any schema change.




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