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  1. Hive
  2. HIVE-12898

Hive should support ORC block skipping on nested fields

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    Details

    • Type: Improvement
    • Status: Open
    • Priority: Major
    • Resolution: Unresolved
    • Affects Version/s: 0.14.0, 1.2.1
    • Fix Version/s: None
    • Component/s: ORC

      Description

      Hive supports predicate pushdown (block skipping) for ORC tables only on top-level fields. Hive should also support block skipping on nested fields (within structs).

      Example top-level: the following query selects 0 rows, using a predicate on top-level column foo. We also see 0 INPUT_RECORDS in the summary:

      SET hive.tez.exec.print.summary=true;
      CREATE TABLE t_toplevel STORED AS ORC AS SELECT 23 AS foo;
      SELECT * FROM t_toplevel WHERE foo=42 ORDER BY foo;
      
      [...]
      VERTICES         TOTAL_TASKS  FAILED_ATTEMPTS KILLED_TASKS DURATION_SECONDS    CPU_TIME_MILLIS     GC_TIME_MILLIS  INPUT_RECORDS   OUTPUT_RECORDS
      Map 1                      1                0            0             1.22              2,640                102              0                0
      

      Example nested: the following query also selects 0 rows, but using a predicate on nested column foo.bar. Unfortunately we see 1 INPUT_RECORDS in the summary:

      SET hive.tez.exec.print.summary=true;
      CREATE TABLE t_nested STORED AS ORC AS SELECT NAMED_STRUCT('bar', 23) AS foo;
      SELECT * FROM t_nested WHERE foo.bar=42 ORDER BY foo;
      
      [...]
      VERTICES         TOTAL_TASKS  FAILED_ATTEMPTS KILLED_TASKS DURATION_SECONDS    CPU_TIME_MILLIS     GC_TIME_MILLIS  INPUT_RECORDS   OUTPUT_RECORDS
      Map 1                      1                0            0             3.66              5,210                 68              1                0
      

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              • Assignee:
                ashish-kumar-sharma Ashish Sharma
                Reporter:
                akatose Michael Haeusler
              • Votes:
                4 Vote for this issue
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                12 Start watching this issue

                Dates

                • Created:
                  Updated: