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Arina Ielchiieva reassigned DRILL-6791: --------------------------------------- Assignee: Paul Rogers (was: Arina Ielchiieva) > Merge scan projection framework into master > ------------------------------------------- > > Key: DRILL-6791 > URL: https://issues.apache.org/jira/browse/DRILL-6791 > Project: Apache Drill > Issue Type: Improvement > Affects Versions: 1.15.0 > Reporter: Paul Rogers > Assignee: Paul Rogers > Priority: Major > Fix For: 1.15.0 > > > 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. -- This message was sent by Atlassian JIRA (v7.6.3#76005)