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https://issues.apache.org/jira/browse/HIVE-25075?focusedWorklogId=590973&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-590973
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ASF GitHub Bot logged work on HIVE-25075:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 29/Apr/21 13:13
Start Date: 29/Apr/21 13:13
Worklog Time Spent: 10m
Work Description: rbalamohan opened a new pull request #2234:
URL: https://github.com/apache/hive/pull/2234
Details are mentioned in https://issues.apache.org/jira/browse/HIVE-25075
### What changes were proposed in this pull request?
Because of Hive.get(), it ends up closing the current connection for every
partition.
So during external table load with large number of partitions, it
re-establishes the connection to HMS for every partition which slows down
processing.
Patch fixes this issue by invoking getMSC() instead of Hive.get()
Ref:
https://github.com/apache/hive/blob/master/ql/src/java/org/apache/hadoop/hive/ql/metadata/Hive.java#L401
https://github.com/apache/hive/blob/master/ql/src/java/org/apache/hadoop/hive/ql/metadata/Hive.java#L390
https://github.com/apache/hive/blob/master/ql/src/java/org/apache/hadoop/hive/ql/metadata/Hive.java#L374
https://github.com/apache/hive/blob/master/ql/src/java/org/apache/hadoop/hive/ql/metadata/Hive.java#L477
### Why are the changes needed?
performance
### Does this PR introduce _any_ user-facing change?
No
### How was this patch tested?
Small internal cluster.
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Issue Time Tracking
-------------------
Worklog Id: (was: 590973)
Remaining Estimate: 0h
Time Spent: 10m
> Hive::loadPartitionInternal establishes HMS connection for every partition
> for external tables
> ----------------------------------------------------------------------------------------------
>
> Key: HIVE-25075
> URL: https://issues.apache.org/jira/browse/HIVE-25075
> Project: Hive
> Issue Type: Improvement
> Reporter: Rajesh Balamohan
> Priority: Major
> Time Spent: 10m
> Remaining Estimate: 0h
>
> https://github.com/apache/hive/blob/master/ql/src/java/org/apache/hadoop/hive/ql/metadata/Hive.java#L2522
> {code}
> boolean needRecycle = !tbl.isTemporary()
> &&
> ReplChangeManager.shouldEnableCm(Hive.get().getDatabase(tbl.getDbName()),
> tbl.getTTable());
> {code}
> Hive.get() breaks the current connection with HMS. Due to this, for external
> table partition loads, it establishes HMS connection for partition.
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