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From "Wei Zheng (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HIVE-11848) tables in subqueries don't get locked
Date Tue, 03 May 2016 18:06:12 GMT

    [ https://issues.apache.org/jira/browse/HIVE-11848?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15269229#comment-15269229
] 

Wei Zheng commented on HIVE-11848:
----------------------------------

patch looks good. +1

> tables in subqueries don't get locked
> -------------------------------------
>
>                 Key: HIVE-11848
>                 URL: https://issues.apache.org/jira/browse/HIVE-11848
>             Project: Hive
>          Issue Type: Bug
>          Components: Locking, Transactions
>    Affects Versions: 1.0.0
>            Reporter: Eugene Koifman
>            Assignee: Eugene Koifman
>            Priority: Critical
>         Attachments: HIVE-11848.patch
>
>
> Consider
> {noformat}
> update acidTbl set b=19 where acidTbl.b in(select I.b from nonAcidOrcTbl I where I.a
= 3)
> {noformat}
> noAcidOrcTbl doesn't get locked at all.  (SHARED_WRITE is taken on acidTbl).
> Same for __delete__ with subquery
> This is is because the ReadEntity for nonAcidOrcTbl is skipped by
> {noformat}
>     for (ReadEntity input : plan.getInputs()) {
>       if (!input.needsLock() || input.isUpdateOrDelete()) {
>         // We don't want to acquire readlocks during update or delete as we'll be acquiring
write
>         // locks instead.
>         continue;
>       }
> {noformat}
> whatever sets isUpdateOrDelete() flag doesn't pay attention to whether the table is written
to or not.
> HIVE-10150 was a similar issue, abstractly



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