org.infinispan.statetransfer

Class TransactionSynchronizerInterceptor

java.lang.Object

org.infinispan.interceptors.BaseAsyncInterceptor

org.infinispan.statetransfer.TransactionSynchronizerInterceptor

All Implemented Interfaces:

AsyncInterceptor

public class TransactionSynchronizerInterceptor
extends BaseAsyncInterceptor

With the Non-Blocking State Transfer (NBST) in place it is possible for a transactional command to be forwarded multiple times, concurrently to the same node. This interceptor makes sure that for any given transaction, the interceptor chain, post StateTransferInterceptor, would only allows a single thread to amend a transaction.

E.g. of when this situation might occur:

• 1) Node A broadcasts PrepareCommand to nodes B, C
• 2) Node A leaves cluster, causing new topology to be installed
• 3) The command arrives to B and C, with lower topology than the current one
• 4) Both B and C forward the command to node D
• 5) D executes the two commands in parallel and finds out that A has left, therefore executing RollbackCommand>

This interceptor must placed after the logic that handles command forwarding (StateTransferInterceptor), otherwise we can end up in deadlocks when a command is forwarded in a loop to the same cache: e.g. A→B→C→A. This scenario is possible when we have chained topology changes (see ISPN-2578).

Since:

5.2

Author:

Mircea Markus

Field Summary

Fields inherited from class org.infinispan.interceptors.BaseAsyncInterceptor

cacheConfiguration

Constructor Summary

Constructors

Constructor and Description
TransactionSynchronizerInterceptor()

Method Summary

Modifier and Type	Method and Description
Object	visitCommand(InvocationContext ctx, VisitableCommand command) Perform some work for a command invocation.

Methods inherited from class org.infinispan.interceptors.BaseAsyncInterceptor

asyncInvokeNext, asyncInvokeNext, asyncInvokeNext, asyncValue, delayedNull, delayedValue, delayedValue, invokeNext, invokeNextAndExceptionally, invokeNextAndFinally, invokeNextAndHandle, invokeNextThenAccept, invokeNextThenApply, isSuccessfullyDone, makeStage, setNextInterceptor, valueOrException

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

TransactionSynchronizerInterceptor

public TransactionSynchronizerInterceptor()

Method Detail

visitCommand

public Object visitCommand(InvocationContext ctx,
                           VisitableCommand command)
                    throws Throwable

Description copied from interface: AsyncInterceptor

Perform some work for a command invocation. The interceptor is responsible for invoking the next interceptor in the chain, using BaseAsyncInterceptor.invokeNext(InvocationContext, VisitableCommand) or the other methods in BaseAsyncInterceptor.

Returns:

Either a regular value, or an InvocationStage created by the BaseAsyncInterceptor methods.

Throws:

Throwable