db-derby-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Anders Morken (JIRA)" <derby-...@db.apache.org>
Subject [jira] Commented: (DERBY-1704) Allow more concurrency in the lock manager
Date Wed, 13 Sep 2006 07:54:22 GMT
    [ http://issues.apache.org/jira/browse/DERBY-1704?page=comments#action_12434378 ] 
            
Anders Morken commented on DERBY-1704:
--------------------------------------

Oh, forgot to mention that the tests were run on a SMP machine - an old Sun Enterprise 450
with 4x400MHz CPUs (and a bit error on bit 12 on memory module 1701 - yay ECC. ;-). The Derby
release used was 10.1.3.1 - (417277), the official release from the web page. If time permits
we'll see about testing Knut Anders' patch with DTrace as well.

> Allow more concurrency in the lock manager
> ------------------------------------------
>
>                 Key: DERBY-1704
>                 URL: http://issues.apache.org/jira/browse/DERBY-1704
>             Project: Derby
>          Issue Type: Improvement
>          Components: Services, Performance
>    Affects Versions: 10.2.1.0
>            Reporter: Knut Anders Hatlen
>            Priority: Minor
>         Attachments: 1cpu.png, 2cpu.png, 8cpu.png, split-hashtables.diff, split-hashtables.stat
>
>
> I have seen indications of severe monitor contention in SinglePool
> (the current lock manager) when multiple threads access a Derby
> database concurrently. When a thread wants to lock an object, it needs
> to obtain the monitor for both SinglePool and LockSet (both of them
> are global synchronization points). This leads to poor scalability.
> We should investigate how to allow more concurrency in the lock
> manager, and either extend SinglePool or implement a new manager.

-- 
This message is automatically generated by JIRA.
-
If you think it was sent incorrectly contact one of the administrators: http://issues.apache.org/jira/secure/Administrators.jspa
-
For more information on JIRA, see: http://www.atlassian.com/software/jira

        

Mime
View raw message