private static String getDefaultNodeConfigurationCacheKey( PubSubService.UniqueIdentifier uniqueIdentifier, boolean isLeafType )
    {
        return uniqueIdentifier.getServiceId() + "|" + isLeafType;
    }
Writes large changesets to the database, using batches and transactions when
available.

The 'delete' list takes precedence over the 'add' list: when an item exists
on both lists, it is removed (and not re-added) to the database.

To prevent duplicates to exist in the database, this method will attempt to
remove all items to-be-added from the database, before re-adding them.

Note that multiple attempts to write items to the DB are made:
1) insert all pending items in a single batch
2) if the batch insert fails, retry by inserting each item separately

@param addList A list of items to be added to the database.
@param delList A list of items to be removed from the database.
xmppserver/src/main/java/org/jivesoftware/openfire/pubsub/DefaultPubSubPersistenceProvider.java