[jira] [Work started] (HIVE-22888) Rewrite checkLock inner select with JOIN operator

["Denys Kuzmenko (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/HIVE-22888?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Work on HIVE-22888 started by Denys Kuzmenko.
---------------------------------------------
> Rewrite checkLock inner select with JOIN operator
> -------------------------------------------------
>
>                 Key: HIVE-22888
>                 URL: https://issues.apache.org/jira/browse/HIVE-22888
>             Project: Hive
>          Issue Type: Improvement
>          Components: Locking
>            Reporter: Denys Kuzmenko
>            Assignee: Denys Kuzmenko
>            Priority: Major
>         Attachments: HIVE-22888.1.patch, HIVE-22888.2.patch
>
>
> - Created extra (db, tbl, part) index on HIVE_LOCKS table;
> - Replaced inner select under checkLocks using multiple IN statements with JOIN operator; 
> generated query looks like :
> {code}
> SELECT LS.* FROM ( 
>     SELECT HL_LOCK_EXT_ID, HL_LOCK_INT_ID, HL_DB, HL_TABLE, HL_PARTITION, HL_LOCK_STATE, HL_LOCK_TYPE, HL_TXNID FROM HIVE_LOCKS 
>     WHERE HL_LOCK_EXT_ID < 14138) LS 
> INNER JOIN (
>     SELECT HL_DB, HL_TABLE, HL_PARTITION FROM HIVE_LOCKS WHERE HL_LOCK_EXT_ID = 14138) LBC 
> ON LS.HL_DB = LBC.HL_DB 
>     AND (LS.HL_TABLE IS NULL OR LS.HL_TABLE = LBC.HL_TABLE 
>     AND (LS.HL_PARTITION IS NULL OR LS.HL_PARTITION = LBC.HL_PARTITION))
> WHERE LBC.HL_LOCK_TYPE='e'
>    OR LBC.HL_LOCK_TYPE='w' AND LS.HL_LOCK_TYPE IN ('w','e')
>    OR LBC.HL_LOCK_TYPE='r' AND (LS.HL_LOCK_TYPE='e' or LS.HL_LOCK_TYPE='w' and LS.HL_LOCK_STATE='w')
> LIMIT 1;
> {code}



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