c21 commented on a change in pull request #32198:
URL: https://github.com/apache/spark/pull/32198#discussion_r618781460
##########
File path:
sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/FileFormatDataWriter.scala
##########
@@ -255,25 +331,180 @@ class DynamicPartitionDataWriter(
}
if (isBucketed) {
currentBucketId = nextBucketId
- statsTrackers.foreach(_.newBucket(currentBucketId.get))
}
fileCounter = 0
- newOutputWriter(currentPartitionValues, currentBucketId)
+ renewCurrentWriter(currentPartitionValues, currentBucketId,
closeCurrentWriter = true)
} else if (description.maxRecordsPerFile > 0 &&
recordsInFile >= description.maxRecordsPerFile) {
- // Exceeded the threshold in terms of the number of records per file.
- // Create a new file by increasing the file counter.
- fileCounter += 1
- assert(fileCounter < MAX_FILE_COUNTER,
- s"File counter $fileCounter is beyond max value $MAX_FILE_COUNTER")
+ increaseFileCounter(currentPartitionValues, currentBucketId)
+ }
+ writeRecord(record)
+ }
+}
+
+/**
+ * Dynamic partition writer with concurrent writers, meaning multiple
concurrent writers are opened
+ * for writing.
+ *
+ * The process has the following steps:
+ * - Step 1: Maintain a map of output writers per each partition and/or
bucket columns. Keep all
+ * writers opened and write rows one by one.
+ * - Step 2: If number of concurrent writers exceeds limit, sort rest of rows
on partition and/or
+ * bucket column(s). Write rows one by one, and eagerly close the
writer when finishing
+ * each partition and/or bucket.
+ *
+ * Caller is expected to call `writeWithIterator()` instead of `write()` to
write records.
+ */
+class DynamicPartitionDataConcurrentWriter(
+ description: WriteJobDescription,
+ taskAttemptContext: TaskAttemptContext,
+ committer: FileCommitProtocol,
+ concurrentOutputWriterSpec: ConcurrentOutputWriterSpec)
+ extends BaseDynamicPartitionDataWriter(description, taskAttemptContext,
committer) {
+
+ /** Wrapper class to index a unique concurrent output writer. */
+ private case class WriterIndex(
+ var partitionValues: Option[UnsafeRow],
+ var bucketId: Option[Int])
+
+ /** Wrapper class for status of a unique concurrent output writer. */
+ private class WriterStatus(
+ var outputWriter: OutputWriter,
+ var recordsInFile: Long,
+ var fileCounter: Int)
+
+ /**
+ * State to indicate if we are falling back to sort-based writer.
+ * Because we first try to use concurrent writers, its initial value is
false.
+ */
+ private var sorted: Boolean = false
+ private val concurrentWriters = mutable.HashMap[WriterIndex, WriterStatus]()
+ private val currentWriterId = WriterIndex(None, None)
+
+ /**
+ * Release resources for all concurrent output writers.
+ */
+ override protected def releaseResources(): Unit = {
+ currentWriter = null
+ concurrentWriters.values.foreach(status => {
+ if (status.outputWriter != null) {
+ try {
+ status.outputWriter.close()
+ } finally {
+ status.outputWriter = null
+ }
+ }
+ })
+ concurrentWriters.clear()
+ }
- newOutputWriter(currentPartitionValues, currentBucketId)
+ override def write(record: InternalRow): Unit = {
+ val nextPartitionValues = if (isPartitioned)
Some(getPartitionValues(record)) else None
+ val nextBucketId = if (isBucketed) Some(getBucketId(record)) else None
+
+ if (currentWriterId.partitionValues != nextPartitionValues ||
+ currentWriterId.bucketId != nextBucketId) {
+ // See a new partition or bucket - write to a new partition dir (or a
new bucket file).
+ if (currentWriter != null) {
+ if (!sorted) {
+ // Update writer status in concurrent writers map, because the
writer is probably needed
+ // again later for writing other rows.
+ updateCurrentWriterStatusInMap()
+ } else {
+ // Remove writer status in concurrent writers map and release
current writer resource,
+ // because the writer is not needed any more.
+ concurrentWriters.remove(currentWriterId)
+ releaseCurrentWriter()
+ }
+ }
+
+ if (isBucketed) {
+ currentWriterId.bucketId = nextBucketId
+ }
+ if (isPartitioned && currentWriterId.partitionValues !=
nextPartitionValues) {
+ currentWriterId.partitionValues = Some(nextPartitionValues.get.copy())
+ if (!concurrentWriters.contains(currentWriterId)) {
+
statsTrackers.foreach(_.newPartition(currentWriterId.partitionValues.get))
+ }
+ }
+ retrieveWriterInMap()
}
- val outputRow = getOutputRow(record)
- currentWriter.write(outputRow)
- statsTrackers.foreach(_.newRow(outputRow))
- recordsInFile += 1
+
+ if (description.maxRecordsPerFile > 0 &&
+ recordsInFile >= description.maxRecordsPerFile) {
+ increaseFileCounter(currentWriterId.partitionValues,
currentWriterId.bucketId)
+ // Update writer status in concurrent writers map, as a new writer is
created.
+ updateCurrentWriterStatusInMap()
+ }
+ writeRecord(record)
+ }
+
+ /**
+ * Write iterator of records with concurrent writers.
+ */
+ override def writeWithIterator(iterator: Iterator[InternalRow]): Unit = {
+ while (iterator.hasNext && !sorted) {
+ write(iterator.next())
+ }
+
+ if (iterator.hasNext) {
+ clearCurrentWriterStatus()
+ val sorter = concurrentOutputWriterSpec.createSorter()
+ val sortIterator =
sorter.sort(iterator.asInstanceOf[Iterator[UnsafeRow]])
+ while (sortIterator.hasNext) {
+ write(sortIterator.next())
+ }
+ }
+ }
+
+ /**
+ * Update current writer status in map.
+ */
+ private def updateCurrentWriterStatusInMap(): Unit = {
+ val status = concurrentWriters(currentWriterId)
+ status.outputWriter = currentWriter
+ status.recordsInFile = recordsInFile
+ status.fileCounter = fileCounter
+ }
+
+ /**
+ * Retrieve writer in map, or create a new writer if not exists.
+ */
+ private def retrieveWriterInMap(): Unit = {
+ if (concurrentWriters.contains(currentWriterId)) {
+ val status = concurrentWriters(currentWriterId)
+ currentWriter = status.outputWriter
+ recordsInFile = status.recordsInFile
+ fileCounter = status.fileCounter
+ } else {
+ fileCounter = 0
+ renewCurrentWriter(
+ currentWriterId.partitionValues,
+ currentWriterId.bucketId,
+ closeCurrentWriter = false)
+ concurrentWriters.put(
Review comment:
@imback82 - I am hesitating to introduce assertion as this are on row
execution path unless it's very necessary. Are you worried about
`concurrentWriters.size > concurrentOutputWriterSpec.maxWriters`? Note this is
the only place in file to add new keys into map (the only `.put()` call), and
it has the check for size immediately at next line.
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