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https://issues.apache.org/jira/browse/HIVE-16334?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15950604#comment-15950604
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Peter Vary commented on HIVE-16334:
-----------------------------------
Thanks for the reviews [~stakiar], [~ekoifman]!
@sahil: The user can query the detailed lock information by the {{show locks
customers extended;}}
It will output this:
{code}
+----------------------------------------------------+---------+--+
| tab_name | mode |
+----------------------------------------------------+---------+--+
| default@customers | SHARED |
| LOCK_QUERYID:hive_20170331023232_0a132ae3-d304-4b29-950f-68dce115bb9a | NULL
|
| LOCK_TIME:1490952750561 | NULL |
| LOCK_MODE:IMPLICIT | NULL |
| LOCK_QUERYSTRING:select * from customers c1 join customers c2 on c1.id=c2.id
| NULL |
+----------------------------------------------------+---------+--+
{code}
This helps the user to understand why is the table locked. I think it is good
to have the possibility to print the actual query string, but truncate it. What
do you think?
Peter
> Query lock contains the query string, which can cause OOM on ZooKeeper
> ----------------------------------------------------------------------
>
> Key: HIVE-16334
> URL: https://issues.apache.org/jira/browse/HIVE-16334
> Project: Hive
> Issue Type: Improvement
> Components: Locking
> Reporter: Peter Vary
> Assignee: Peter Vary
> Attachments: HIVE-16334.patch
>
>
> When there are big number of partitions in a query this will result in a huge
> number of locks on ZooKeeper. Since the query object contains the whole query
> string this might cause serious memory pressure on the ZooKeeper services.
> It would be good to have the possibility to truncate the query strings that
> are written into the locks
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