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https://issues.apache.org/jira/browse/DRILL-3623?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14979500#comment-14979500
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ASF GitHub Bot commented on DRILL-3623:
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Github user jinfengni commented on the pull request:
https://github.com/apache/drill/pull/193#issuecomment-152034091
Sudheesh and I feel this new approach is more like a big optimization step
towards solving the performance issue for "limit 0" query, rather than hack
solution : 1) It shows quite significantly reduction in query time, from
hundreds of seconds to couple of seconds in some cases. That's a big
improvement. 2) it would benefit not only schema-based query, but also
schema-less query, while the original approach would only apply for
schema-based query.
I agree we should continue to optimize "limit 0" query. But for now, I
think this new approach has its own merits.
The aggregation /implicit casting are the two things that I can think of,
if we go with the schema-based approach.
> Hive query hangs with limit 0 clause
> ------------------------------------
>
> Key: DRILL-3623
> URL: https://issues.apache.org/jira/browse/DRILL-3623
> Project: Apache Drill
> Issue Type: Bug
> Components: Storage - Hive
> Affects Versions: 1.1.0
> Environment: MapR cluster
> Reporter: Andries Engelbrecht
> Assignee: Jinfeng Ni
> Fix For: Future
>
>
> Running a select * from hive.table limit 0 does not return (hangs).
> Select * from hive.table limit 1 works fine
> Hive table is about 6GB with 330 files with parquet using snappy compression.
> Data types are int, bigint, string and double.
> Querying directory with parquet files through the DFS plugin works fine
> select * from dfs.root.`/user/hive/warehouse/database/table` limit 0;
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