[infinispan-issues] [JBoss JIRA] Issue Comment Edited: (ISPN-1131) Acquire (write) locks at prepare time even on local node

[Mircea Markus (JIRA)]

    [ https://issues.jboss.org/browse/ISPN-1131?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12603758#comment-12603758 ] 

Mircea Markus edited comment on ISPN-1131 at 6/30/11 9:36 AM:
--------------------------------------------------------------

In infinispan 5.1 this will be default locking model, replacing the current one. 
In order to enable it use the following configuration element:
{code:xml}
<locking mode="optimistic"
         isolationLevel="READ_COMMITTED" />
{code}

The LockingInterceptor needs to be changed in order not to acquire read locks for writes:

{code:java}
public Object visitGetKeyValueCommand(InvocationContext ctx, GetKeyValueCommand command) throws Throwable {
      try {
         entryFactory.wrapEntryForReading(ctx, command.getKey());
         return invokeNextInterceptor(ctx, command);
      } finally {
         doAfterCall(ctx);
      }
   }

{code}
Also following logic will be appended to LockingInterceptor.visitPrepareCommand, before invokeNextInterceptor:
{code:java}
      if (ctx.isOriginLocal()) {
         for (WriteCommand wc : command.getModifications()) {
            acquireLock(wc);
         }
      }
{code}

acquireLock() in the code above acquires locks exactly the same way LockingInterceptor does for a given command.
E.g. acquireLock(PutKeyValueCommand) is equivalent with LockingInterceptor.visitPutKeyValueCommand(..)
if in distributed mode, the acquire lock only acquires a lock if the key(s) within WriteCommand map to the local node
if lock cannot be acquired for a key all acquired locks are release and the transaction is marked for rollback


      was (Author: mircea.markus):
    In infinispan 5.1 this will be default locking model, enabled by default. 
In order to enable it use the following configuration element:
{code:xml}
<locking mode="optimistic"
         isolationLevel="READ_COMMITTED" />
{code}

The LockingInterceptor needs to be changed in order not to acquire read locks for writes:

{code:java}
public Object visitGetKeyValueCommand(InvocationContext ctx, GetKeyValueCommand command) throws Throwable {
      try {
         entryFactory.wrapEntryForReading(ctx, command.getKey());
         return invokeNextInterceptor(ctx, command);
      } finally {
         doAfterCall(ctx);
      }
   }

{code}
Also following logic will be appended to LockingInterceptor.visitPrepareCommand, before invokeNextInterceptor:
{code:java}
      if (ctx.isOriginLocal()) {
         for (WriteCommand wc : command.getModifications()) {
            acquireLock(wc);
         }
      }
{code}

acquireLock() in the code above acquires locks exactly the same way LockingInterceptor does for a given command.
E.g. acquireLock(PutKeyValueCommand) is equivalent with LockingInterceptor.visitPutKeyValueCommand(..)
if in distributed mode, the acquire lock only acquires a lock if the key(s) within WriteCommand map to the local node
if lock cannot be acquired for a key all acquired locks are release and the transaction is marked for rollback

  
> Acquire (write) locks at prepare time even on local node
> --------------------------------------------------------
>
>                 Key: ISPN-1131
>                 URL: https://issues.jboss.org/browse/ISPN-1131
>             Project: Infinispan
>          Issue Type: Feature Request
>            Reporter: Mircea Markus
>            Assignee: Mircea Markus
>              Labels: locking, optimization
>             Fix For: 5.1.0.BETA1, 5.1.0.Final
>
>
> Detailed here, as the 1st improvement: http://community.jboss.org/wiki/PossibleLockingImprovements  

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