There is an error in the RC cache when the server goes through a restart.
Basically the problem is associated with the listenerId given to clients. When
the server starts up it initializes that listenerId to 0. As clients connect
they are given a listenerId and an event queue is created to handle sending
changes to the client. The problem occurs when the server restarts. On
restart the server resets its listenerId sequence. Clients that reconnect are
allowed to continue using their listenerId. When new clients connect the
server does not check to see if the listenerId it is assigning out is in
conflict with an existing listenerid. Also when previous clients reconnect the
server does not check to see if it has given out the listenerid that the
reconnecting client is using.
What you end up with is one or more clients that never receive updates from the
server.
Has anyone else experienced this bug and is there a workaround or a fix to it?
Here is the snippet of code I am looking at. It comes from
org.apache.jcs.auxiliary.remote.server.RemoteCacheServer.addCacheListener
// synchronized ( listenerId )
synchronized ( ICacheListener.class )
{
long id = 0;
try
{
id = listener.getListenerId();
// clients problably shouldn't do this.
if ( id == 0 )
{
// must start at one so the next gets recognized
long listenerIdB = nextListenerId();
if ( log.isDebugEnabled() )
{
log.debug( "listener id=" + ( listenerIdB & 0xff ) + "
addded for cache [" + cacheName
+ "], listenerAddress [" + listenerAddress + "]" );
}
listener.setListenerId( listenerIdB );
id = listenerIdB;
// in case it needs synchronization
if ( log.isInfoEnabled() )
{
log.info( "adding vm listener under new id = [" +
listenerIdB + "], listenerAddress ["
+ listenerAddress + "]" );
}
}
else
{
if ( log.isInfoEnabled() )
{
log.info( "adding listener under existing id = [" + id
+ "], listenerAddress ["
+ listenerAddress + "]" );
}
// should confirm the the host is the same as we have on
// record, just in case a client has made a mistake.
}
// relate the type to an id
this.idTypeMap.put( new Long( id ), new Integer( remoteType ) );
}
catch ( IOException ioe )
{
log.error( "Problem setting listener id, listenerAddress [" +
listenerAddress + "]", ioe );
}
CacheEventQueueFactory fact = new CacheEventQueueFactory();
ICacheEventQueue q = fact.createCacheEventQueue( listener, id,
cacheName, rcsa.getEventQueuePoolName(),
rcsa.getEventQueueTypeFactoryCode() );
eventQMap.put( new Long( listener.getListenerId() ), q );
