db-derby-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Knut Anders Hatlen (JIRA)" <j...@apache.org>
Subject [jira] Commented: (DERBY-5073) Derby deadlocks without recourse on simultaneous correlated subqueries
Date Wed, 02 Mar 2011 21:48:37 GMT

    [ https://issues.apache.org/jira/browse/DERBY-5073?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13001687#comment-13001687
] 

Knut Anders Hatlen commented on DERBY-5073:
-------------------------------------------

Hi Karl,

It might be useful to include the STATE column from the diagnostic table, so that we see which
locks are granted and which are being waited for. Then we may be able to reconstruct the wait
graph and see if it contains any cycles that the deadlock detection algorithm has missed.

> Derby deadlocks without recourse on simultaneous correlated subqueries
> ----------------------------------------------------------------------
>
>                 Key: DERBY-5073
>                 URL: https://issues.apache.org/jira/browse/DERBY-5073
>             Project: Derby
>          Issue Type: Bug
>            Reporter: Karl Wright
>
> When the following two queries are run against tables that contain the necessary fields,
using multiple threads, Derby deadlocks and none of the queries ever returns.  Derby apparently
detects no deadlock condition, either.
> SELECT t0.* FROM jobqueue t0 WHERE EXISTS(SELECT 'x' FROM carrydown t1 WHERE t1.parentidhash
IN (?) AND t1.childidhash=t0.dochash AND t0.jobid=t1.jobid) AND t0.jobid=?
> SELECT t0.* FROM jobqueue t0 WHERE EXISTS(SELECT 'x' FROM carrydown t1 WHERE t1.parentidhash
IN (?) AND t1.childidhash=t0.dochash AND t0.jobid=t1.jobid AND t1.newField=?) AND t0.jobid=?
> This code comes from Apache ManifoldCF, and has occurred when there are five or more
threads trying to execute these two queries at the same time.  Originally we found this on
10.5.3.0.  It was hoped that 10.7.1.1 would fix the problem, but it hasn't.

-- 
This message is automatically generated by JIRA.
-
For more information on JIRA, see: http://www.atlassian.com/software/jira

        

Mime
View raw message