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Posted to issues@hive.apache.org by "Naveen Gangam (Jira)" <ji...@apache.org> on 2020/07/21 01:52:00 UTC
[jira] [Commented] (HIVE-23846) Avoid unnecessary serialization and
deserialization of bitvectors
[ https://issues.apache.org/jira/browse/HIVE-23846?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17161655#comment-17161655 ]
Naveen Gangam commented on HIVE-23846:
--------------------------------------
I have +1'ed the fix on PR.
> Avoid unnecessary serialization and deserialization of bitvectors
> -----------------------------------------------------------------
>
> Key: HIVE-23846
> URL: https://issues.apache.org/jira/browse/HIVE-23846
> Project: Hive
> Issue Type: Bug
> Components: Standalone Metastore
> Reporter: Yu-Wen Lai
> Assignee: Yu-Wen Lai
> Priority: Major
> Labels: pull-request-available
> Time Spent: 0.5h
> Remaining Estimate: 0h
>
> In the method *getNdvEstimator* of <datatype>*ColumnStatsDataInspector*, it will call isSetBitVectors(), in which it serializes the bitvectors again when we already have deserialized bitvectors _ndvEstimator_. For example, we can see this pattern from [LongColumnStatsDataInspector|[https://github.com/apache/hive/blob/master/standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/columnstats/cache/LongColumnStatsDataInspector.java#L106]].
> This method could check if the _ndvEstimator_ is set first so that it won't need to serialize and deserialize back.
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