[jira] [Created] (HUDI-2275) HoodieDeltaStreamerException when using OCC and a second concurrent writer

["Dave Hagman (Jira)" <ji...@apache.org>]

Dave Hagman created HUDI-2275:
---------------------------------

             Summary: HoodieDeltaStreamerException when using OCC and a second concurrent writer
                 Key: HUDI-2275
                 URL: https://issues.apache.org/jira/browse/HUDI-2275
             Project: Apache Hudi
          Issue Type: Bug
          Components: DeltaStreamer, Spark Integration, Writer Core
    Affects Versions: 0.9.0
            Reporter: Dave Hagman


 I am trying to utilize [Optimistic Concurrency Control|https://hudi.apache.org/docs/concurrency_control] in order to allow two writers to update a single table simultaneously. The two writers are:
 * Writer A: Deltastreamer job consuming continuously from Kafka
 * Writer B: A spark datasource-based writer that is consuming parquet files out of S3
 * Table Type: Copy on Write

 

After a few commits from each writer the deltastreamer will fail with the following exception:
org.apache.hudi.exception.HoodieDeltaStreamerException: Unable to find previous checkpoint. Please double check if this table was indeed built via delta streamer. Last Commit :Option\{val=[20210803165741__commit__COMPLETED]}, Instants :[[20210803165741__commit__COMPLETED]], CommitMetadata={
  "partitionToWriteStats" : {
...
 

What appears to be happening is a lack of commit isolation between the two writers
Writer B (spark datasource writer) will land commits which are eventually picked up by Writer A (Delta Streamer). This is an issue because the Delta Streamer needs checkpoint information which the spark datasource of course does not include in its commits. My understanding was that OCC was built for this very purpose (among others). 

OCC config for Delta Streamer:
hoodie.write.concurrency.mode=optimistic_concurrency_control
hoodie.cleaner.policy.failed.writes=LAZY
hoodie.write.lock.provider=org.apache.hudi.client.transaction.lock.ZookeeperBasedLockProvider
hoodie.write.lock.zookeeper.url=<zk_host>
hoodie.write.lock.zookeeper.port=2181
hoodie.write.lock.zookeeper.lock_key=writer_lock
hoodie.write.lock.zookeeper.base_path=/hudi-write-locks
 

OCC config for spark datasource:
// Multi-writer concurrency
.option("hoodie.cleaner.policy.failed.writes", "LAZY")
.option("hoodie.write.concurrency.mode", "optimistic_concurrency_control")
.option(
        "hoodie.write.lock.provider",
        org.apache.hudi.client.transaction.lock.ZookeeperBasedLockProvider.class.getCanonicalName()
)
.option("hoodie.write.lock.zookeeper.url", jobArgs.zookeeperHost)
.option("hoodie.write.lock.zookeeper.port", jobArgs.zookeeperPort)
.option("hoodie.write.lock.zookeeper.lock_key", "writer_lock")
.option("hoodie.write.lock.zookeeper.base_path", "/hudi-write-locks")
h3. Steps to Reproduce:
 * Start a deltastreamer job against some table Foo
 * In parallel, start writing to the same table Foo using spark datasource writer
 * Note that after a few commits from each the deltastreamer is likely to fail with the above exception when the datasource writer creates non-isolated inflight commits

NOTE: I have not tested this with two of the same datasources (ex. two deltastreamer jobs)



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