[CASSANDRA-4954] Store trigger jar file dependencies in system keyspace

• Type: New Feature
• Status: Resolved
• Priority: Normal
• Resolution: Won't Fix
• Fix Version/s: 2.2.0 beta 1
• Assignee: Unassigned
• Reporter: Patrick McFadin
• Created: 13/Nov/12 14:41
• Updated: 16/Apr/19 09:32
• Resolved: 20/Jan/15 15:09

Description

The implementation of triggers requires the use of jar files to be stored in the local filesystem, per node. See (https://issues.apache.org/jira/browse/CASSANDRA-1311)

I'm proposing that instead of using the filesystem, jars would be stored in the system keyspace. This would greatly reduce the operational complexity of implementing triggers on multiple node clusters. Some benefits would include:

• Triggers and dependencies would be part of a snapshot for backup and restore
• Every node would have a consistent version
• Everything needed for the trigger would be a part of bootstrap

Some details to start the conversation:

• Have a list of jars for each trigger be made available via JMX
• Expose the jar upload using CQL when trigger is created (USING FILE x)
• Store the version number or date for each jar
• Implement a classloader trigger when jars are updated
• Provide some sort of guarantee that triggers aren't active until all nodes have the same version of jar(s)