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https://issues.apache.org/jira/browse/HIVE-12898?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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ASF GitHub Bot updated HIVE-12898:
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Labels: pull-request-available (was: )
> 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: 0.14.0, 1.2.1
> Reporter: Michael Haeusler
> Assignee: Ashish Sharma
> Priority: Major
> Labels: pull-request-available
>
> 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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