[
https://issues.apache.org/jira/browse/HIVE-9741?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14335754#comment-14335754
]
Sergey Shelukhin commented on HIVE-9741:
----------------------------------------
The problem otherwise (if it's called outside) is that setting ansi_quotes will
happen in some arbitrary transaction, not related to the query.
Why is this call needed there at all (other than is auto-create is on and the
methods are called)?
+one small nit in RB
> Refactor MetaStoreDirectSql constructor by removing DB queries out of
> critical section
> --------------------------------------------------------------------------------------
>
> Key: HIVE-9741
> URL: https://issues.apache.org/jira/browse/HIVE-9741
> Project: Hive
> Issue Type: Bug
> Components: Metastore
> Affects Versions: 1.0.0
> Reporter: Xiaobing Zhou
> Assignee: Xiaobing Zhou
> Attachments: HIVE-9741.1.patch, HIVE-9741.2.patch, HIVE-9741.3.patch,
> HIVE-9741.4.patch
>
>
> MetaStoreDirectSql constructor is querying DB to determine dbType, which
> leads to too many DB queries to make megastore slow as ObjectStore.setConf
> might be called frequently. Moreover, ObjectStore.setConf begins/ends with
> lock acquire/release, if the underlying DB hangs somehow, lock is never
> released and all hereafter incoming requests are blocked.
> Two points:
> 1. Using getProductName based JDBC driver to get dbType info.
> 2. Since metastore auto-creaton is disabled by default, it'd better bypass
> ensureDbInit() and runTestQuery() in order to avoid DB queries within
> critical section of setConf.
> Here’s stack trace:
> MetaStoreDirectSql.determineDbType(...)
> MetaStoreDirectSql.MetaStoreDirectSql(...)
> ObjectStore.initialize(...)
> ObjectStore.setConf(…)
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
