That makes sense, I'll give it a try, thanks! 2010/2/26 Mattias Persson <[email protected]>: > 2010/2/26 Raul Raja Martinez <[email protected]>: >> Hi Mattias, >> >> Thanks for the docs. >> I'm trying to solve this issue now and here is the problem I'm facing... >> >> Where it says in the wiki: >> "Rewrite your code, making sure that such scenarios won't happen. >> Run your deadlock-prone code in a try-catch(DeadlockDetectedException) >> block and just rerun the entire transaction if such an exception is >> caught." >> >> My transactions start and end in an interceptor that provides advice >> to method invokations. >> The invokations happen inside a thread pool concurrently. >> >> This is what the interceptor looks like. I have no way to recover from >> the deadlock. Are you implying in that advice that >> I should synchronize in the operation that is causing the write lock? >> Is there anyway to configure Neo to wait on deadlock for a release up >> to certain time? >> If I reissue a method call that is transactional other state not >> related to the neo transactions such as indexes, etc... may modify >> other state objects, I'd rather have the transaction wait for release >> and continue as other transactions are completing. > To make the executing thread wait would result in a deadlock, that's > why the exception is thrown so that isn't really an option. > > Regarding state: if you're referring to components in neo4j, they all > handle state correctly if a transaction is rolled back (in this case > where a DeadlockDetectedException is thrown)... even the IndexService > and such components so that won't be a problem. >> >> Here is the code for the interceptor. The advised methods are >> Runnables that get executed async by a threadpool. >> >> /** >> * A method interceptor that provides transaction advice around a >> method invocation opening and closing a transaction accordingly >> */ >> public class Neo4JTransactionAdviceInterceptor implements MethodInterceptor { >> >> private final static Logger log = >> Logger.getLogger(Neo4JTransactionAdviceInterceptor.class); >> >> private GraphDatabaseService neoService; >> >> public void setNeoService(GraphDatabaseService neoService) { >> this.neoService = neoService; >> } >> >> /** >> * provides transaction advice around a method invocation opening >> and closing a transaction accordingly >> * >> * @param invocation the method invocation joinpoint >> * @return the result of the call to {...@link >> * org.aopalliance.intercept.Joinpoint#proceed()}, might >> be intercepted by the >> * interceptor. >> * @throws Throwable if the interceptors or the >> * target-object throws an exception. >> */ >> public Object invoke(MethodInvocation invocation) throws Throwable { >> Transaction tx = neoService.beginTx(); >> Object result = null; >> try { >> result = invocation.proceed(); >> tx.success(); >> } catch (DeadlockDetectedException e) { >> tx.failure(); >> log.debug("deadlock detected for invocation " + invocation >> + " result: " + result + " transaction: " + tx); >> } catch (Throwable t) { >> tx.failure(); >> throw t; >> } finally { >> tx.finish(); >> } >> return result; >> } >> } >> >> > > How about making your code look something like (I removed unecessary > tx.failure() calls, see > http://wiki.neo4j.org/content/Transactions#Controlling_success): > > public Object invoke(MethodInvocation invocation) throws Throwable { > Object result = null; > for ( int i = 0; i < 10; i++ ) { > Transaction tx = neoService.beginTx(); > try { > result = invocation.proceed(); > tx.success(); > return result; > } catch (DeadlockDetectedException e) { > log.debug("deadlock detected for invocation " + invocation > + " result: " + result + " transaction: " + tx); > } finally { > tx.finish(); > } > } > return result; > } > > Where 10 is the number of retries to do before giving up. It may not > look very elegant, but there's really no "silver bullet" for the the > deadlock problem. > > -- > Mattias Persson, [[email protected]] > Neo Technology, www.neotechnology.com > _______________________________________________ > Neo mailing list > [email protected] > https://lists.neo4j.org/mailman/listinfo/user >
-- Raul Raja _______________________________________________ Neo mailing list [email protected] https://lists.neo4j.org/mailman/listinfo/user
