[
https://issues.apache.org/jira/browse/JCR-314?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12493608
]
Marcel Reutegger commented on JCR-314:
--------------------------------------
Oliver, thank you for your comment. However I do not see how a deadlock may
occur between jackrabbit and the DB used in a persistence manager. Deadlocks
always require that locks are acquired in a circular way. That's never the case
between Jackrabbit and the DB. A call that returns from the DB will always have
released all DB locks.
I'd appreciate if you were a bit more specific, e.g. provide a wait-for graph
that shows a deadlock situation.
> In any case there should be a timeout for Jackrabbit locks. For one to to
> free locks that have
> never been freed, because some thread forgot to free them.
I disagree. This would clearly be a bug in Jackrabbit and should rather be
fixed than worked around with timeouts.
> Fine grained locking in SharedItemStateManager
> ----------------------------------------------
>
> Key: JCR-314
> URL: https://issues.apache.org/jira/browse/JCR-314
> Project: Jackrabbit
> Issue Type: Improvement
> Components: core
> Affects Versions: 0.9, 1.0, 1.0.1, 1.1, 1.1.1, 1.2.1, 1.2.2, 1.2.3
> Reporter: Marcel Reutegger
> Attachments: FineGrainedISMLocking.patch, ISMLocking.patch
>
>
> The SharedItemStateManager (SISM) currently uses a simple read-write lock to
> ensure data consistency. Store operations to the PersistenceManager (PM) are
> effectively serialized.
> We should think about more sophisticated locking to allow concurrent writes
> on the PM.
> One possible approach:
> If a transaction is currently storing data in a PM a second transaction may
> check if the set of changes does not intersect with the first transaction. If
> that is the case it can safely store its data in the PM.
> This fine grained locking must also be respected when reading from the SISM.
> A read request for an item that is currently being stored must be blocked
> until the store is finished.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
