[jira] Reopened: (DERBY-2327) Reduce monitor contention in LockSet

["Daniel John Debrunner (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/DERBY-2327?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Daniel John Debrunner reopened DERBY-2327:
------------------------------------------


Since a commit:
 "DERBY-2327: Reduce monitor contention in LockSet Added a new LockSet implementation which uses the classes in java.util.concurrent to achieve more concurrency."

I see these build issues.

/home/djd/cruise/cruisecontrol-bin-2.6.1/projects/derby_build/trunk/java/engine/org/apache/derby/impl/services/locks/ConcurrentLockSet.java:83: generics are not supported in -source 1.4

(try -source 1.5 to enable generics)

private final ConcurrentHashMap<Lockable, Entry> locks;

^

/home/djd/cruise/cruisecontrol-bin-2.6.1/projects/derby_build/trunk/java/engine/org/apache/derby/impl/services/locks/ConcurrentLockSet.java:278: for-each loops are not supported in -source 1.4

(try -source 1.5 to enable for-each loops)

for (Entry e : seenByDeadlockDetection) {

> Reduce monitor contention in LockSet
> ------------------------------------
>
>                 Key: DERBY-2327
>                 URL: https://issues.apache.org/jira/browse/DERBY-2327
>             Project: Derby
>          Issue Type: Sub-task
>          Components: Performance, Services
>    Affects Versions: 10.3.0.0
>            Reporter: Knut Anders Hatlen
>         Assigned To: Knut Anders Hatlen
>            Priority: Minor
>             Fix For: 10.3.0.0
>
>         Attachments: 2cpu-join.png, 2cpu-select.png, 8cpu-join.png, 8cpu-select.png, ConcurrentHashMap.diff, derby-2327-1a.diff, derby-2327-1a.stat, derby-2327-2a.diff, derby-2327-2a.stat, derby-2327-3a.diff, derby-2327-4a.diff, derby-2327-4a.stat, niagara-join.png, niagara-select.png
>
>
> When multiple threads enter the lock manager, only one can access the hash table in LockSet. To improve scalability on multiple CPUs, it should be possible to have more than one thread accessing the lock table at the same time.

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