[ https://issues.apache.org/jira/browse/DERBY-4565?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12841197#action_12841197 ] 

Knut Anders Hatlen commented on DERBY-4565:
-------------------------------------------

In addition to the "too much contention" errors, my logs show that the test also frequently fails with lock timeouts or deadlocks when I run the test using the configuration specified above, probably because the update of the system table is escalated to the main transaction. Here's a sample deadlock:

Failed Statement is: insert into t_3_5( a ) values ( next value for seq_3 )
ERROR 40001: A lock could not be obtained due to a deadlock, cycle of locks and waiters is:
Lock : ROW, SYSSEQUENCES, (1,10)
  Waiting XID : {37240, X} , TEST, insert into t_3_5( a ) values ( next value for seq_3 )
  Granted XID : {36715, X} 
Lock : ROW, SYSSEQUENCES, (1,8)
  Waiting XID : {36715, X} , TEST, insert into t_1_9( a ) values ( next value for seq_1 )
  Granted XID : {37240, X} 
. The selected victim is XID : 37240.

> Create concurrency test to stress sequence generators.
> ------------------------------------------------------
>
>                 Key: DERBY-4565
>                 URL: https://issues.apache.org/jira/browse/DERBY-4565
>             Project: Derby
>          Issue Type: Task
>          Components: SQL, Test
>    Affects Versions: 10.6.0.0
>            Reporter: Rick Hillegas
>            Assignee: Rick Hillegas
>         Attachments: derby-4565-01-ad-firstRev.diff
>
>
> Create a concurrency test to find bottlenecks and bugs in sequence generators.

-- 
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.