[HIVE-12898] Hive should support ORC block skipping on nested fields

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 0.14.0, 1.2.1
• Component/s: ORC
• Labels: pull-request-available
• Assignee: Ashish Sharma
• Reporter: Michael Haeusler
• Created: 21/Jan/16 12:19
• Updated: 24/Jun/20 00:26

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

Issue Links

• is a parent of: ORC-323 Predicate push down for nested fields
• relates to: HIVE-7214 Support predicate pushdown for complex data types in ORCFile
• relates to: HIVE-19103 Nested structure Projection Push Down in Hive with ORC
• links to: GitHub Pull Request #346
• links to: GitHub Pull Request #346