[SAMZA-374] Need to be able to change SSP Grouper

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Won't Fix
• Affects Version/s: 0.8.0
• Fix Version/s: 0.8.0
• Component/s: container
• Assignee: Unassigned
• Reporter: Chris Riccomini
• Created: 08/Aug/14 19:00
• Updated: 19/Aug/14 19:58
• Resolved: 19/Aug/14 19:58

Description

I recently ran a job with checkpointing enabled. The default grouper was used (group by partition). I then decided that I wanted to increase parallelism, so I set the grouper to group by SSP. This cause the container to get wedged in this loop:

2014-08-08 18:56:06 VerifiableProperties [INFO] Verifying properties
2014-08-08 18:56:06 VerifiableProperties [INFO] Property client.id is overridden to samza_checkpoint_manager-repartition_by_treeid-i001-1407524103759-2
2014-08-08 18:56:06 VerifiableProperties [INFO] Property metadata.broker.list is overridden to kafka-vip-e:10251
2014-08-08 18:56:06 VerifiableProperties [INFO] Property request.timeout.ms is overridden to 60000
2014-08-08 18:56:06 ClientUtils$ [INFO] Fetching metadata from broker id:0,host:kafka-vip-e,port:10251 with correlation id 7 for 1 topic(s) Set(__samza_checkpoint_ver_1_for_my-job_i001)
2014-08-08 18:56:06 BlockingChannel [DEBUG] Created socket with SO_TIMEOUT = 60000 (requested 60000), SO_RCVBUF = 43690 (requested -1), SO_SNDBUF = 102400 (requested 102400).
2014-08-08 18:56:06 SyncProducer [INFO] Connected to kafka-vip-e:10251 for producing
2014-08-08 18:56:06 SyncProducer [INFO] Disconnecting from kafka-vip-e:10251
2014-08-08 18:56:06 ClientUtils$ [DEBUG] Successfully fetched metadata for 1 topic(s) Set(__samza_checkpoint_ver_1_for_my-job_i001)
2014-08-08 18:56:06 KafkaCheckpointManager [INFO] Connecting to leader app196.:10251 for topic __samza_checkpoint_ver_1_for_my-job_i001 and to fetch all checkpoint messages.
2014-08-08 18:56:06 KafkaCheckpointManager [INFO] Got offset 13 for topic __samza_checkpoint_ver_1_for_my-job_i001 and partition 0. Attempting to fetch messages for changelog partition mapping.
2014-08-08 18:56:06 SimpleConsumer [DEBUG] Disconnecting from app196.:10251
2014-08-08 18:56:06 BlockingChannel [DEBUG] Created socket with SO_TIMEOUT = 60000 (requested 60000), SO_RCVBUF = 65536 (requested 65536), SO_SNDBUF = 8192 (requested -1).
2014-08-08 18:56:06 KafkaCheckpointManager [INFO] Get latest offset 80626 for topic __samza_checkpoint_ver_1_for_my-job_i001 and partition 0.
2014-08-08 18:56:07 SimpleConsumer [DEBUG] Disconnecting from app196.:10251
2014-08-08 18:56:07 KafkaCheckpointManager [WARN] While trying to read last changelog partition mapping entry for topic __samza_checkpoint_ver_1_for_my-job_i001 and partition 0: org.apache.samza.SamzaException: Exception while deserializing checkpoint key. Retrying.
2014-08-08 18:56:07 KafkaCheckpointManager [DEBUG] Exception detail:
org.apache.samza.SamzaException: Exception while deserializing checkpoint key
	at org.apache.samza.checkpoint.kafka.KafkaCheckpointLogKey$.fromBytes(KafkaCheckpointLogKey.scala:177)
	at org.apache.samza.checkpoint.kafka.KafkaCheckpointManager$$anonfun$readLog$1$$anonfun$apply$9.apply(KafkaCheckpointManager.scala:300)
	at org.apache.samza.checkpoint.kafka.KafkaCheckpointManager$$anonfun$readLog$1$$anonfun$apply$9.apply(KafkaCheckpointManager.scala:292)
	at scala.collection.Iterator$class.foreach(Iterator.scala:727)
	at kafka.utils.IteratorTemplate.foreach(IteratorTemplate.scala:32)
	at scala.collection.IterableLike$class.foreach(IterableLike.scala:72)
	at kafka.message.MessageSet.foreach(MessageSet.scala:67)
	at org.apache.samza.checkpoint.kafka.KafkaCheckpointManager$$anonfun$readLog$1.apply(KafkaCheckpointManager.scala:292)
	at org.apache.samza.checkpoint.kafka.KafkaCheckpointManager$$anonfun$readLog$1.apply(KafkaCheckpointManager.scala:254)
	at org.apache.samza.util.ExponentialSleepStrategy.run(ExponentialSleepStrategy.scala:82)
	at org.apache.samza.checkpoint.kafka.KafkaCheckpointManager.readLog(KafkaCheckpointManager.scala:253)
	at org.apache.samza.checkpoint.kafka.KafkaCheckpointManager.readChangeLogPartitionMapping(KafkaCheckpointManager.scala:240)
	at org.apache.samza.util.Util$.getTaskNameToChangeLogPartitionMapping(Util.scala:280)
	at org.apache.samza.job.yarn.SamzaAppMasterTaskManager.<init>(SamzaAppMasterTaskManager.scala:79)
	at org.apache.samza.job.yarn.SamzaAppMaster$.main(SamzaAppMaster.scala:90)
	at org.apache.samza.job.yarn.SamzaAppMaster.main(SamzaAppMaster.scala)
Caused by: org.apache.samza.checkpoint.kafka.DifferingSystemStreamPartitionGrouperFactoryValues: Checkpoint key's SystemStreamPartition Grouper factory (org.apache.samza.container.grouper.stream.GroupByPartitionFactory) does not match value from current configuration (org.apache.samza.container.grouper.stream.GroupBySystemStreamPartitionFactory).  This likely means the SystemStreamPartitionGrouper was changed between job runs, which is not supported.
	at org.apache.samza.checkpoint.kafka.KafkaCheckpointLogKey$.fromBytes(KafkaCheckpointLogKey.scala:170)
	... 15 more
2014-08-08 18:56:17 VerifiableProperties [INFO] Verifying properties
2014-08-08 18:56:17 VerifiableProperties [INFO] Property client.id is overridden to samza_checkpoint_manager-repartition_by_treeid-i001-1407524103759-2
2014-08-08 18:56:17 VerifiableProperties [INFO] Property metadata.broker.list is overridden to kafka-vip-e:10251
2014-08-08 18:56:17 VerifiableProperties [INFO] Property request.timeout.ms is overridden to 60000
2014-08-08 18:56:17 ClientUtils$ [INFO] Fetching metadata from broker id:0,host:kafka-vip-e,port:10251 with correlation id 8 for 1 topic(s) Set(__samza_checkpoint_ver_1_for_my-job_i001)
2014-08-08 18:56:17 BlockingChannel [DEBUG] Created socket with SO_TIMEOUT = 60000 (requested 60000), SO_RCVBUF = 43690 (requested -1), SO_SNDBUF = 102400 (requested 102400).
2014-08-08 18:56:17 SyncProducer [INFO] Connected to kafka-vip-e:10251 for producing
2014-08-08 18:56:17 SyncProducer [INFO] Disconnecting from kafka-vip-e:10251
2014-08-08 18:56:17 ClientUtils$ [DEBUG] Successfully fetched metadata for 1 topic(s) Set(__samza_checkpoint_ver_1_for_my-job_i001)
2014-08-08 18:56:17 KafkaCheckpointManager [INFO] Connecting to leader app196.:10251 for topic __samza_checkpoint_ver_1_for_my-job_i001 and to fetch all checkpoint messages.
2014-08-08 18:56:17 KafkaCheckpointManager [INFO] Got offset 14 for topic __samza_checkpoint_ver_1_for_my-job_i001 and partition 0. Attempting to fetch messages for changelog partition mapping.
2014-08-08 18:56:17 SimpleConsumer [DEBUG] Disconnecting from app196.:10251
2014-08-08 18:56:17 BlockingChannel [DEBUG] Created socket with SO_TIMEOUT = 60000 (requested 60000), SO_RCVBUF = 65536 (requested 65536), SO_SNDBUF = 8192 (requested -1).
2014-08-08 18:56:17 KafkaCheckpointManager [INFO] Get latest offset 80626 for topic __samza_checkpoint_ver_1_for_my-job_i001 and partition 0.
2014-08-08 18:56:17 SimpleConsumer [DEBUG] Disconnecting from app196.:10251
2014-08-08 18:56:17 KafkaCheckpointManager [WARN] While trying to read last changelog partition mapping entry for topic __samza_checkpoint_ver_1_for_my-job_i001 and partition 0: org.apache.samza.SamzaException: Exception while deserializing checkpoint key. Retrying.
2014-08-08 18:56:17 KafkaCheckpointManager [DEBUG] Exception detail:
org.apache.samza.SamzaException: Exception while deserializing checkpoint key
	at org.apache.samza.checkpoint.kafka.KafkaCheckpointLogKey$.fromBytes(KafkaCheckpointLogKey.scala:177)
	at org.apache.samza.checkpoint.kafka.KafkaCheckpointManager$$anonfun$readLog$1$$anonfun$apply$9.apply(KafkaCheckpointManager.scala:300)
	at org.apache.samza.checkpoint.kafka.KafkaCheckpointManager$$anonfun$readLog$1$$anonfun$apply$9.apply(KafkaCheckpointManager.scala:292)
	at scala.collection.Iterator$class.foreach(Iterator.scala:727)
	at kafka.utils.IteratorTemplate.foreach(IteratorTemplate.scala:32)
	at scala.collection.IterableLike$class.foreach(IterableLike.scala:72)
	at kafka.message.MessageSet.foreach(MessageSet.scala:67)
	at org.apache.samza.checkpoint.kafka.KafkaCheckpointManager$$anonfun$readLog$1.apply(KafkaCheckpointManager.scala:292)
	at org.apache.samza.checkpoint.kafka.KafkaCheckpointManager$$anonfun$readLog$1.apply(KafkaCheckpointManager.scala:254)
	at org.apache.samza.util.ExponentialSleepStrategy.run(ExponentialSleepStrategy.scala:82)
	at org.apache.samza.checkpoint.kafka.KafkaCheckpointManager.readLog(KafkaCheckpointManager.scala:253)
	at org.apache.samza.checkpoint.kafka.KafkaCheckpointManager.readChangeLogPartitionMapping(KafkaCheckpointManager.scala:240)
	at org.apache.samza.util.Util$.getTaskNameToChangeLogPartitionMapping(Util.scala:280)
	at org.apache.samza.job.yarn.SamzaAppMasterTaskManager.<init>(SamzaAppMasterTaskManager.scala:79)
	at org.apache.samza.job.yarn.SamzaAppMaster$.main(SamzaAppMaster.scala:90)
	at org.apache.samza.job.yarn.SamzaAppMaster.main(SamzaAppMaster.scala)
Caused by: org.apache.samza.checkpoint.kafka.DifferingSystemStreamPartitionGrouperFactoryValues: Checkpoint key's SystemStreamPartition Grouper factory (org.apache.samza.container.grouper.stream.GroupByPartitionFactory) does not match value from current configuration (org.apache.samza.container.grouper.stream.GroupBySystemStreamPartitionFactory).  This likely means the SystemStreamPartitionGrouper was changed between job runs, which is not supported.
	at org.apache.samza.checkpoint.kafka.KafkaCheckpointLogKey$.fromBytes(KafkaCheckpointLogKey.scala:170)
	... 15 more

I'm knowingly breaking grouping semantics because my job doesn't need it. As I recall, this was discussed in SAMZA-123, and we were all worried about people accidentally breaking their state/grouping, so we hard fail when the grouper is changed. The problem is, I can't change the checkpoint topic name, nor is it easy for me to delete the checkpoint messages in the topic, so I'm kind of stuck.

Issue Links

• relates to: SAMZA-123 Move topic partition grouping to the AM and generalize
• relates to: SAMZA-348 Configure Samza jobs through a stream
• relates to: KAFKA-1397 delete topic is not working