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https://issues.apache.org/jira/browse/HIVE-21841?focusedWorklogId=261182&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-261182
]
ASF GitHub Bot logged work on HIVE-21841:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 17/Jun/19 06:29
Start Date: 17/Jun/19 06:29
Worklog Time Spent: 10m
Work Description: ashutosh-bapat 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_r294150033
##########
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:
Yes. That's how it's configurable without this feature. The threads may run
in metastores or in HS2 where this configuration is enabled.
A leader HMS (esp. in cloud environment where this feature is intended to be
used), will not have enough compute capacity. In that case, user may configure
HS2 instance/s to run the compaction or it may configure an HMS/es to do so.
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Issue Time Tracking
-------------------
Worklog Id: (was: 261182)
Time Spent: 2h (was: 1h 50m)
> 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: 2h
> 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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