[CASSANDRA-6089] client_only example does not work

• Type: Bug
• Status: Resolved
• Priority: Low
• Resolution: Fixed
• Fix Version/s: 1.2.11, 2.0.2
• Severity: Low
• Assignee: Mikhail Panchenko
• Reporter: Mikhail Panchenko

Authors

Mikhail Panchenko

Reviewers

Aleksey Yeschenko

• Tester: Mikhail Panchenko
• Created: 24/Sep/13 20:10
• Updated: 16/Apr/19 09:32
• Resolved: 25/Sep/13 19:12

Description

client_only example fails out of the box with:

13/09/24 11:44:53 INFO gms.Gossiper: Node /127.0.0.1 is now part of the cluster
13/09/24 11:44:53 INFO gms.Gossiper: InetAddress /127.0.0.1 is now UP
13/09/24 11:44:53 ERROR concurrent.DebuggableThreadPoolExecutor: Error in ThreadPoolExecutor
java.lang.NullPointerException
  at org.apache.cassandra.service.MigrationManager.maybeScheduleSchemaPull(MigrationManager.java:113)
	at org.apache.cassandra.service.MigrationManager.onAlive(MigrationManager.java:95)
	at org.apache.cassandra.gms.Gossiper.markAlive(Gossiper.java:803)
	at org.apache.cassandra.gms.Gossiper.handleMajorStateChange(Gossiper.java:846)
	at org.apache.cassandra.gms.Gossiper.applyStateLocally(Gossiper.java:931)
	at org.apache.cassandra.gms.GossipDigestAck2VerbHandler.doVerb(GossipDigestAck2VerbHandler.java:50)
	at org.apache.cassandra.net.MessageDeliveryTask.run(MessageDeliveryTask.java:56)
	at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:895)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:918)
	at java.lang.Thread.run(Thread.java:680)
Exception in thread "GossipStage:1" java.lang.NullPointerException
	at org.apache.cassandra.service.MigrationManager.maybeScheduleSchemaPull(MigrationManager.java:113)
	at org.apache.cassandra.service.MigrationManager.onAlive(MigrationManager.java:95)
	at org.apache.cassandra.gms.Gossiper.markAlive(Gossiper.java:803)
	at org.apache.cassandra.gms.Gossiper.handleMajorStateChange(Gossiper.java:846)
	at org.apache.cassandra.gms.Gossiper.applyStateLocally(Gossiper.java:931)
	at org.apache.cassandra.gms.GossipDigestAck2VerbHandler.doVerb(GossipDigestAck2VerbHandler.java:50)
	at org.apache.cassandra.net.MessageDeliveryTask.run(MessageDeliveryTask.java:56)
	at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:895)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:918)
	at java.lang.Thread.run(Thread.java:680)

I've tested this both on the 1.2.8 tag and with 1.2 latest.

The line in question is

if (Schema.instance.getVersion().equals(theirVersion) || !shouldPullSchemaFrom(endpoint))

Seems that Schema.instance.getVersion() returns null in the client_only case. Adding a Schema.instance.getVersion() == null as another || in the conditional appears to fix it, but I don't remember the codepaths well enough to confidently say that that's the correct thing to do.