[ 
https://issues.apache.org/jira/browse/HIVE-21841?focusedWorklogId=261148&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-261148
 ]

ASF GitHub Bot logged work on HIVE-21841:
-----------------------------------------

                Author: ASF GitHub Bot
            Created on: 17/Jun/19 05:16
            Start Date: 17/Jun/19 05:16
    Worklog Time Spent: 10m 
      Work Description: maheshk114 commented on pull request #668: HIVE-21841 : 
Add configuration to specify the hostname of HMS leader …to run housekeeping 
tasks in.
URL: https://github.com/apache/hive/pull/668#discussion_r294131880
 
 

 ##########
 File path: 
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/HiveMetaStore.java
 ##########
 @@ -10050,21 +10080,31 @@ public void run() {
           while (!startedServing.get()) {
             startCondition.await();
           }
-          startCompactorInitiator(conf);
+
+          if (isLeader) {
+            startCompactorInitiator(conf);
+            startCompactorCleaner(conf);
+            startRemoteOnlyTasks(conf);
+            startStatsUpdater(conf);
+            HiveMetaStore.HMSHandler.startAlwaysTaskThreads(conf);
+          }
+
+          // The leader HMS may not necessarily have sufficient compute 
capacity required to run
+          // actual compaction work. So it can run on a non-leader HMS with 
sufficient capacity
+          // or a configured HS2 instance.
           if (MetastoreConf.getVar(conf, 
MetastoreConf.ConfVars.HIVE_METASTORE_RUNWORKER_IN).equals("metastore")) {
 
 Review comment:
   so this worker may run on all metastore ?
 
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Issue Time Tracking
-------------------

    Worklog Id:     (was: 261148)

> Leader election in HMS to run housekeeping tasks.
> -------------------------------------------------
>
>                 Key: HIVE-21841
>                 URL: https://issues.apache.org/jira/browse/HIVE-21841
>             Project: Hive
>          Issue Type: New Feature
>    Affects Versions: 4.0.0
>            Reporter: Ashutosh Bapat
>            Assignee: Ashutosh Bapat
>            Priority: Major
>              Labels: pull-request-available
>             Fix For: 4.0.0
>
>         Attachments: HIVE-21841.01.patch, HIVE-21841.02.patch
>
>          Time Spent: 40m
>  Remaining Estimate: 0h
>
> HMS performs housekeeping tasks. When there are multiple HMSes we need to 
> have a leader HMS elected which will carry out those housekeeping tasks. 
> These tasks include execution of compaction tasks, auto-discovering 
> partitions for external tables, generation of compaction tasks, repl thread 
> etc.
> Note that, though the code for compaction tasks, auto-discovery of partitions 
> etc. is in Hive, the actual tasks are initiated by an HMS configured to do 
> so. So, leader election is required only for HMS and not for HS2.



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