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  1. Apache Drill
  2. DRILL-6791

Merge scan projection framework into master

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    Details

    • Type: Improvement
    • Status: Resolved
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: 1.15.0
    • Fix Version/s: 1.15.0
    • Component/s: None
    • Labels:

      Description

      Merge the next set of "result set loader" code into master via a PR. This one covers the "schema projection" mechanism which:

      • Handles none (SELECT COUNT(*)), some (SELECT a, b, x) and all (SELECT *) projection.
      • Handles null columns (for projection a column "x" that does not exist in the base table.)
      • Handles constant columns as used for file metadata (AKA "implicit" columns).
      • Handle schema persistence: the need to reuse the same vectors across different scanners
      • Provides a framework for consuming externally-supplied metadata
      • Since we don't yet have a way to provide "real" metadata, obtains metadata hints from previous batches and from the projection list (a.b implies that "a" is a map, c[0] implies that "c" is an array, etc.)
      • Handles merging the set of data source columns and null columns to create the final output batch.

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              • Assignee:
                Paul.Rogers Paul Rogers
                Reporter:
                Paul.Rogers Paul Rogers
                Reviewer:
                Arina Ielchiieva
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                  Updated:
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