diff --git a/sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/MetadataLog.scala b/sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/MetadataLog.scala index 78d6be17df05af8885f5b5b1fe057c17df15b0d7..9e2604c9c069f0888ce32da2596fdc00ed8fa6ba 100644 --- a/sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/MetadataLog.scala +++ b/sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/MetadataLog.scala @@ -24,6 +24,7 @@ package org.apache.spark.sql.execution.streaming * - Allow the user to query the latest batch id. * - Allow the user to query the metadata object of a specified batch id. * - Allow the user to query metadata objects in a range of batch ids. + * - Allow the user to remove obsolete metadata */ trait MetadataLog[T] { diff --git a/sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/StreamExecution.scala b/sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/StreamExecution.scala index a1aae61107baf53a9571ea08066c7487086ef345..220f77dc24ce064daaa2220812f418adf4ba25dc 100644 --- a/sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/StreamExecution.scala +++ b/sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/StreamExecution.scala @@ -290,6 +290,13 @@ class StreamExecution( assert(offsetLog.add(currentBatchId, availableOffsets.toCompositeOffset(sources)), s"Concurrent update to the log. Multiple streaming jobs detected for $currentBatchId") logInfo(s"Committed offsets for batch $currentBatchId.") + + // Now that we have logged the new batch, no further processing will happen for + // the previous batch, and it is safe to discard the old metadata. + // Note that purge is exclusive, i.e. it purges everything before currentBatchId. + // NOTE: If StreamExecution implements pipeline parallelism (multiple batches in + // flight at the same time), this cleanup logic will need to change. + offsetLog.purge(currentBatchId) } else { awaitBatchLock.lock() try { diff --git a/sql/core/src/test/scala/org/apache/spark/sql/streaming/StreamingQuerySuite.scala b/sql/core/src/test/scala/org/apache/spark/sql/streaming/StreamingQuerySuite.scala index 9d58315c200312670741023d2159ca3092554760..d3e2cab1b8bd3596d6376b096f44b5ed7618d7e1 100644 --- a/sql/core/src/test/scala/org/apache/spark/sql/streaming/StreamingQuerySuite.scala +++ b/sql/core/src/test/scala/org/apache/spark/sql/streaming/StreamingQuerySuite.scala @@ -125,6 +125,30 @@ class StreamingQuerySuite extends StreamTest with BeforeAndAfter { ) } + testQuietly("StreamExecution metadata garbage collection") { + val inputData = MemoryStream[Int] + val mapped = inputData.toDS().map(6 / _) + + // Run 3 batches, and then assert that only 1 metadata file is left at the end + // since the first 2 should have been purged. + testStream(mapped)( + AddData(inputData, 1, 2), + CheckAnswer(6, 3), + AddData(inputData, 1, 2), + CheckAnswer(6, 3, 6, 3), + AddData(inputData, 4, 6), + CheckAnswer(6, 3, 6, 3, 1, 1), + + AssertOnQuery("metadata log should contain only one file") { q => + val metadataLogDir = new java.io.File(q.offsetLog.metadataPath.toString) + val logFileNames = metadataLogDir.listFiles().toSeq.map(_.getName()) + val toTest = logFileNames // Workaround for SPARK-17475 + assert(toTest.size == 1 && toTest.head == "2") + true + } + ) + } + /** * A [[StreamAction]] to test the behavior of `StreamingQuery.awaitTermination()`. *