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Posted to issues@hive.apache.org by "Denys Kuzmenko (Jira)" <ji...@apache.org> on 2020/05/04 13:13:00 UTC
[jira] [Updated] (HIVE-23349) ACID: Concurrent MERGE INSERT
operations produce duplicates
[ https://issues.apache.org/jira/browse/HIVE-23349?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Denys Kuzmenko updated HIVE-23349:
----------------------------------
Attachment: HIVE-23349.1.patch
> ACID: Concurrent MERGE INSERT operations produce duplicates
> -----------------------------------------------------------
>
> Key: HIVE-23349
> URL: https://issues.apache.org/jira/browse/HIVE-23349
> Project: Hive
> Issue Type: Bug
> Components: Transactions
> Reporter: Denys Kuzmenko
> Assignee: Denys Kuzmenko
> Priority: Major
> Attachments: HIVE-23349.1.patch
>
>
> 2 concurrent MERGE INSERT operations generate duplicates due to lack of locking.
> MERGE INSERT is treated as regular INSERT, it acquires SHARED_READ lock that doesn't prevent other SHARED_READs. We should use EXCL_WRITE lock here or SHARED_WRITE if hive.txn.write.xlock=false;
> {code}
> create table target (a int, b int) stored as orc TBLPROPERTIES ('transactional'='true')");
> insert into target values (1,2), (3,4)
> create table source (a int, b int)
> {code}
> execute in parallel:
> {code}
> insert into source values (5,6), (7,8)
> {code}
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