Re: Remote Synchronizer exceptions
Re: Remote Synchronizer exceptions
- Subject: Re: Remote Synchronizer exceptions
- From: Theodore Petrosky <email@hidden>
- Date: Wed, 21 Jan 2015 11:48:47 -0500
if you are interested, I have ERJGroupsSynchronizer set up with jGroups
3.6.1. I could zip it up and you could try it, if you like.
There are some internals that had to be adjusted, but when I updated
ERJGroupsSynchronizer, I worked directly with Bela (jGroups author) to
understand the changes needed.
In a nutshell, he eliminated his Exception checking and changed to use
the Java Exceptions. remove the section:
if
(ERXProperties.booleanForKeyWithDefault("er.extensions.jgroupsSynchronizer.autoReconnect",
true)) {
_channel.setOpt(Channel.AUTO_RECONNECT, Boolean.TRUE);
}
as (in his words) Shunning was removed a long time ago.
there are a couple of others and he said, <bela__> tedpet: I also
suggest use a config file shipped with the version you download, e.g.
udp.xml, and then make slight modifications to it, if needed"
Or if I could figure this out, I would push my changes up to Wonder!
Ted
On 1/20/15 7:40 AM, OC wrote:
Indeed, 2.6.8 it is. I'll try to upgrade, thanks!
(Is there some trick to upgrade in a smart way, so as I will not have to manually re-check the current version when I am next time upgrading the complete WOnder? At the moment I can't see one, but that might just mean I'm blind.)
Thanks a lot,
OC
On 19. 1. 2015, at 19:02, Theodore Petrosky <email@hidden> wrote:
are you using the default version of ERJGroupsSynchronizer? that was jgroups 2.6.8 they are up to version 3.6.1.
I seem to recall that in a project I had to update jgroups.
Just a thought. I had a similar problem with JasperReports and updating to the newest (almost) version fixed the issue.
Ted
On 1/19/15 12:48 PM, OC wrote:
Hello there,
to sync changes betwixt instances, I am using Remote Synchronizer with the following setup:
===
er.extensions.ERXObjectStoreCoordinatorPool.maxCoordinators=3
er.extensions.remoteSynchronizer.enabled=true
er.extensions.remoteSynchronizer=er.jgroups.ERJGroupsSynchronizer
er.extensions.jgroupsSynchronizer.multicastAddress=230.0.0.1
er.extensions.jgroupsSynchronizer.multicastPort=9753
er.extensions.jgroupsSynchronizer.localBindAddress=127.0.0.1
er.extensions.jgroupsSynchronizer.groupName=REBOIS_SYNC
===
Most time, it works excellently.
Occassionally though, I'm getting exceptions like this
===
15:15:02.574 INFO Received 97 changes from 127.0.0.1:60979 //log:er.extensions.remoteSynchronizer.ERXRemoteSynchronizer [Incoming-1,REBOIS_SYNC,127.0.0.1:62546]
15:15:02.985 ERROR Exception condition 379. Optimistic locking: multiple transaction conflict detected.at com.frontbase.jdbc.FBJErrorMetaData.errorMessageAtIndex(Unknown Source)
===
(full stack below). It does make sense: while my own save code is written to handle optimistic exceptions properly, the Remote Synchronizer self-evidently is not. But the outcome is rather grave, namely, instances which contain different values in their EO stacks, and which either present the different values to users, or even report weird errors.
(The last case, which lead me to this, was one instance removing an object from a relationship and deleting it from the database. Another instance alas, most probably due to the aforementioned exception, has not been informed that the object was removed from a relationship, and fell to databaseContextFailedToFetchObject. Ick.)
How do you solve this problem? To be frank, I can't see a solution, but for writing my own Remote Synchronizer, which I would rather do without for time reasons...
Thanks for any advice,
OC
=== full stack trace of the exception in case it helps any ===
15:15:02.574 INFO Received 97 changes from 127.0.0.1:60979 //log:er.extensions.remoteSynchronizer.ERXRemoteSynchronizer [Incoming-1,REBOIS_SYNC,127.0.0.1:62546]
15:15:02.985 ERROR Exception condition 379. Optimistic locking: multiple transaction conflict detected.at com.frontbase.jdbc.FBJErrorMetaData.errorMessageAtIndex(Unknown Source)
at com.frontbase.jdbc.FBJErrorMetaData.getExceptionChain(Unknown Source)
at com.frontbase.jdbc.FBJConnection.checkMetaData(Unknown Source)
at com.frontbase.jdbc.FBJConnection.commit(Unknown Source)
at com.webobjects.jdbcadaptor.JDBCContext.commitTransaction(JDBCContext.java:452)
at com.webobjects.jdbcadaptor.JDBCChannel._endFetch(JDBCChannel.java:417)
at com.webobjects.jdbcadaptor.JDBCChannel.fetchRow(JDBCChannel.java:1458)
at com.webobjects.eoaccess.EODatabaseChannel._fetchObject(EODatabaseChannel.java:321)
at com.webobjects.eoaccess.EODatabaseContext._objectsWithFetchSpecificationEditingContext(EODatabaseContext.java:3071)
at er.extensions.eof.ERXDatabaseContext._objectsWithFetchSpecificationEditingContext(ERXDatabaseContext.java:68)
at com.webobjects.eoaccess.EODatabaseContext.objectsWithFetchSpecification(EODatabaseContext.java:3195)
at com.webobjects.eocontrol.EOObjectStoreCoordinator.objectsWithFetchSpecification(EOObjectStoreCoordinator.java:488)
at com.webobjects.eocontrol.EOEditingContext.objectsWithFetchSpecification(EOEditingContext.java:4069)
at er.extensions.eof.ERXEC.objectsWithFetchSpecification(ERXEC.java:1308)
at com.webobjects.eocontrol.EOEditingContext.objectsWithFetchSpecification(EOEditingContext.java:4444)
at er.extensions.eof.ERXEOGlobalIDUtilities.fetchObjectsWithGlobalIDs(ERXEOGlobalIDUtilities.java:290)
at er.extensions.eof.ERXObjectStoreCoordinatorSynchronizer$ProcessChangesQueue$UpdateCacheChangeProcessor.processCacheChange(ERXObjectStoreCoordinatorSynchronizer.java:393)
at er.extensions.eof.ERXObjectStoreCoordinatorSynchronizer$ProcessChangesQueue.processRemoteChange(ERXObjectStoreCoordinatorSynchronizer.java:560)
at er.extensions.eof.ERXObjectStoreCoordinatorSynchronizer$ProcessChangesQueue.run(ERXObjectStoreCoordinatorSynchronizer.java:622)
at java.lang.Thread.run(Thread.java:695)
Exception condition 363. Transaction rollback.
//log:er.extensions.eof.ERXObjectStoreCoordinatorSynchronizer [ERXOSCProcessChanges]
JDBCAdaptorException: Exception condition 379. Optimistic locking: multiple transaction conflict detected.
at com.webobjects.jdbcadaptor.JDBCContext.commitTransaction(JDBCContext.java:455)
... skipped 4 stack elements
at er.extensions.eof.ERXDatabaseContext._objectsWithFetchSpecificationEditingContext(ERXDatabaseContext.java:68)
... skipped 1 stack elements
at com.webobjects.eocontrol.EOObjectStoreCoordinator.objectsWithFetchSpecification(EOObjectStoreCoordinator.java:488)
at com.webobjects.eocontrol.EOEditingContext.objectsWithFetchSpecification(EOEditingContext.java:4069)
at er.extensions.eof.ERXEC.objectsWithFetchSpecification(ERXEC.java:1308)
at com.webobjects.eocontrol.EOEditingContext.objectsWithFetchSpecification(EOEditingContext.java:4444)
at er.extensions.eof.ERXEOGlobalIDUtilities.fetchObjectsWithGlobalIDs(ERXEOGlobalIDUtilities.java:290)
at er.extensions.eof.ERXObjectStoreCoordinatorSynchronizer$ProcessChangesQueue$UpdateCacheChangeProcessor.processCacheChange(ERXObjectStoreCoordinatorSynchronizer.java:393)
at er.extensions.eof.ERXObjectStoreCoordinatorSynchronizer$ProcessChangesQueue.processRemoteChange(ERXObjectStoreCoordinatorSynchronizer.java:560)
at er.extensions.eof.ERXObjectStoreCoordinatorSynchronizer$ProcessChangesQueue.run(ERXObjectStoreCoordinatorSynchronizer.java:622)
... skipped 1 stack elements
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