[jira] [Created] (HIVE-12898) Hive should support ORC block skipping on nested fields

["Michael Haeusler (JIRA)" <ji...@apache.org>]

Michael Haeusler created HIVE-12898:
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             Summary: Hive should support ORC block skipping on nested fields
                 Key: HIVE-12898
                 URL: https://issues.apache.org/jira/browse/HIVE-12898
             Project: Hive
          Issue Type: Improvement
          Components: ORC
    Affects Versions: 1.2.1, 0.14.0
            Reporter: Michael Haeusler


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:

{code:sql}
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
{code}


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:
{code:sql}
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
{code}




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