copeg copeg - 22 days ago 16
Apache Configuration Question

Stop Cassandra Materialized View Build

Is there any way to stop the build of a materialized view in Cassandra (3.7)?

Background: I created two materialized views A and B (full disclosure - I may have attempted to drop them before the build was complete) and those views seem to be perpetually stuck...any attempt to create another view C on the same table seems to hang. Using nodetool

nodetool.viewbuildstatus <keyspace>.<view>


shows a combination of STARTED and UNKNOWN for A and B, and STARTED for views in C. Using cql:

select * from system.views_builds_in_progress


all views are listed, but generation number and last_token have not changed in the last 24hrs (generation_number is in fact null for A).

Answer

Its not documented, but nodetool stop actually takes any compaction type, not just the ones listed (which the view build is one of). So you can simply:

nodetool stop VIEW_BUILD

Or you can hit JMX directly with the org.apache.cassandra.db:type=CompactionManager mbean's stopCompaction operation.

All thats really gonna do is set a flag for the view builder to stop on its next loop. If it threw an uncaught exception or something so its no longer doing anything (worth checking system/output logs) the stop wont do anything either. In that case its not really hurting anything though so can ignore it and retry. Worst case restart the node.

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