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Posted to issues@hive.apache.org by "Rajesh KSV (JIRA)" <ji...@apache.org> on 2018/11/13 07:15:02 UTC
[jira] [Updated] (HIVE-20906) Are Hive locks ephemeral ?
[ https://issues.apache.org/jira/browse/HIVE-20906?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Rajesh KSV updated HIVE-20906:
------------------------------
Summary: Are Hive locks ephemeral ? (was: Hive locks are not really ephemeral)
> Are Hive locks ephemeral ?
> --------------------------
>
> Key: HIVE-20906
> URL: https://issues.apache.org/jira/browse/HIVE-20906
> Project: Hive
> Issue Type: Bug
> Affects Versions: 2.3.0, 2.3.3, 3.1.1
> Reporter: Rajesh KSV
> Priority: Major
> Fix For: 3.1.1
>
> Attachments: ephemeral.patch
>
>
> I am using Hive 2.3.3.
>
> According to docs ([https://cwiki.apache.org/confluence/display/Hive/Locking]), they are ephemeral. But in the Zookeeper and Hive source Code, they seemed to be non-ephemeral.
>
> I ran the following query in Hive.
>
> *lock table discovery.defaultns*
>
> When I see the lock in zookeeper, it doesn't look like ephemeral node.
>
> [zk: localhost:2181(CONNECTED) 55] get /hive_zookeeper_namespace/discovery/defaultns/LOCK-EXCLUSIVE-0000000000
> hive_20181112191555_d6640955-2806-4fa7-9e52-30d04c377a04:1542030355565:EXPLICIT:lock table discovery.defaultns exclusive:10.33.222.139
> cZxid = 0x2400296808
> ctime = Mon Nov 12 19:15:55 IST 2018
> mZxid = 0x2400296808
> mtime = Mon Nov 12 19:15:55 IST 2018
> pZxid = 0x2400296808
> cversion = 0
> dataVersion = 0
> aclVersion = 0
> *ephemeralOwner = 0x0*
> dataLength = 134
> numChildren = 0
>
> Also in the code - [https://github.com/apache/hive/blob/master/ql/src/java/org/apache/hadoop/hive/ql/lockmgr/HiveTxnManagerImpl.java], the lock is KeepAlive/PERSISTENT and not EPHIMERAL. Current code is
>
> *HiveLock lck = lockMgr.lock(new HiveLockObject(tbl, lockData), mode, true);*
> Either the docs are misleading or code is incorrect.
> If docs are correct, then it should be
> *HiveLock lck = lockMgr.lock(new HiveLockObject(tbl, lockData), mode, false);*
> The patch is the same.
> Please correct me if I am wrong. This is my first ever Jira/Patch in Hive
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