When an event server is removed from das_gsa_subscriber
for a given item descriptor—for example, due to a connection timeout—it can be restored in two ways:
Each time the event server sends a cache invalidation event for an item descriptor, it checks whether it is itself listed for that item descriptor in
das_gsa_subscriber
. If it is missing, it prints a warning and adds itself to the table.The
GSARepository
class’scheckSubscriptions()
method can be called periodically on a repository—for example, by a scheduled service—to ensure that all item descriptors defined in that repository to use distributed TCP caching are registered in thedas_gsa_subscriber
table.checkSubscriptions()
queriesdas_gsa_subscriber
for each item descriptor. If the method finds that the repository’s event server is not listed for an item descriptor, it issues a warning and flushes the item type’s cache, in order to safeguard against invalid data. It also adds itself todas_gsa_subscriber
.
Note: das_gsa_subscriber
is updated with repository data only if the repository’s autoUpdateSubscribers
property is set to true (the default).