Tathagata Das created SPARK-26629:
-------------------------------------
Summary: Error with multiple file stream in a query + restart on a
batch that has no data for one file stream
Key: SPARK-26629
URL: https://issues.apache.org/jira/browse/SPARK-26629
Project: Spark
Issue Type: Bug
Components: Structured Streaming
Affects Versions: 2.4.0, 2.3.2, 2.3.1, 2.3.0, 2.4.1
Reporter: Tathagata Das
Assignee: Tathagata Das
When a streaming query has multiple file streams, and there is a batch where
one of the file streams dont have data in that batch, then if the query has to
restart from that, it will throw the following error.
{code}
java.lang.IllegalStateException: batch 1 doesn't exist
at
org.apache.spark.sql.execution.streaming.HDFSMetadataLog$.verifyBatchIds(HDFSMetadataLog.scala:300)
at
org.apache.spark.sql.execution.streaming.FileStreamSourceLog.get(FileStreamSourceLog.scala:120)
at
org.apache.spark.sql.execution.streaming.FileStreamSource.getBatch(FileStreamSource.scala:181)
at
org.apache.spark.sql.execution.streaming.MicroBatchExecution$$anonfun$org$apache$spark$sql$execution$streaming$MicroBatchExecution$$populateStartOffsets$2.apply(MicroBatchExecution.scala:294)
at
org.apache.spark.sql.execution.streaming.MicroBatchExecution$$anonfun$org$apache$spark$sql$execution$streaming$MicroBatchExecution$$populateStartOffsets$2.apply(MicroBatchExecution.scala:291)
at scala.collection.Iterator$class.foreach(Iterator.scala:891)
at scala.collection.AbstractIterator.foreach(Iterator.scala:1334)
at scala.collection.IterableLike$class.foreach(IterableLike.scala:72)
at
org.apache.spark.sql.execution.streaming.StreamProgress.foreach(StreamProgress.scala:25)
at
org.apache.spark.sql.execution.streaming.MicroBatchExecution.org$apache$spark$sql$execution$streaming$MicroBatchExecution$$populateStartOffsets(MicroBatchExecution.scala:291)
at
org.apache.spark.sql.execution.streaming.MicroBatchExecution$$anonfun$runActivatedStream$1$$anonfun$apply$mcZ$sp$1.apply$mcV$sp(MicroBatchExecution.scala:178)
at
org.apache.spark.sql.execution.streaming.MicroBatchExecution$$anonfun$runActivatedStream$1$$anonfun$apply$mcZ$sp$1.apply(MicroBatchExecution.scala:175)
at
org.apache.spark.sql.execution.streaming.MicroBatchExecution$$anonfun$runActivatedStream$1$$anonfun$apply$mcZ$sp$1.apply(MicroBatchExecution.scala:175)
at
org.apache.spark.sql.execution.streaming.ProgressReporter$class.reportTimeTaken(ProgressReporter.scala:251)
at
org.apache.spark.sql.execution.streaming.StreamExecution.reportTimeTaken(StreamExecution.scala:61)
at
org.apache.spark.sql.execution.streaming.MicroBatchExecution$$anonfun$runActivatedStream$1.apply$mcZ$sp(MicroBatchExecution.scala:175)
at
org.apache.spark.sql.execution.streaming.ProcessingTimeExecutor.execute(TriggerExecutor.scala:56)
at
org.apache.spark.sql.execution.streaming.MicroBatchExecution.runActivatedStream(MicroBatchExecution.scala:169)
at
org.apache.spark.sql.execution.streaming.StreamExecution.org$apache$spark$sql$execution$streaming$StreamExecution$$runStream(StreamExecution.scala:295)
at
org.apache.spark.sql.execution.streaming.StreamExecution$$anon$1.run(StreamExecution.scala:205)
{code}
**Reason**
Existing {{HDFSMetadata.verifyBatchIds}} throws error whenever the batchIds
list was empty. In the context of {{FileStreamSource.getBatch}} (where verify
is called) and FileStreamSourceLog (subclass of HDFSMetadata), this is usually
okay because, in a streaming query with one file stream, the batchIds can never
be empty:
A batch is planned only when the FileStreamSourceLog has seen new offset (that
is, there are new data files).
So FileStreamSource.getBatch will be called on X to Y where X will always be >
Y. This calls internally {{HDFSMetadata.verifyBatchIds (X+1, Y)}} with X+1-Y
ids.
For example, {{FileStreamSource.getBatch(4, 5)}} will call {{verify(batchIds =
Seq(5), start = 5, end = 5)}}. However, the invariant of X > Y is not true when
there are two file stream sources, as a batch may be planned even when only one
of the file streams has data. So one of the file stream may not have data,
which can call {{FileStreamSource.getBatch(X, X) -> verify(batchIds =
Seq.empty, start = X+1, end = X) -> failure}}.
Note that FileStreamSource.getBatch(X, X) gets called only when restarting a
query in a batch where a file source did not have data. This is because, in
normal planning of batches, MicroBatchExecution avoids calling
{{FileStreamSource.getBatch(X, X)}} when offset X has not changed. However,
when restarting a stream at such a batch,
{{MicroBatchExecution.populateStartOffsets()}} calls
{{FileStreamSource.getBatch(X, X)}} (DataSource V1 hack to initialize the
source with last known offsets) thus hitting this issue.
**Solution**
The minimum solution (that can be backported) here is to skip verification when
FileStreamSource.getBatch(X, X).
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
---------------------------------------------------------------------
To unsubscribe, e-mail: issues-unsubscr...@spark.apache.org
For additional commands, e-mail: issues-h...@spark.apache.org
