revans2 commented on a change in pull request #29067:
URL: https://github.com/apache/spark/pull/29067#discussion_r458163165
##########
File path:
sql/core/src/main/scala/org/apache/spark/sql/execution/columnar/InMemoryRelation.scala
##########
@@ -85,77 +232,81 @@ case class CachedRDDBuilder(
}
private def buildBuffers(): RDD[CachedBatch] = {
- val output = cachedPlan.output
- val cached = cachedPlan.execute().mapPartitionsInternal { rowIterator =>
- new Iterator[CachedBatch] {
- def next(): CachedBatch = {
- val columnBuilders = output.map { attribute =>
- ColumnBuilder(attribute.dataType, batchSize, attribute.name,
useCompression)
- }.toArray
-
- var rowCount = 0
- var totalSize = 0L
- while (rowIterator.hasNext && rowCount < batchSize
- && totalSize < ColumnBuilder.MAX_BATCH_SIZE_IN_BYTE) {
- val row = rowIterator.next()
-
- // Added for SPARK-6082. This assertion can be useful for
scenarios when something
- // like Hive TRANSFORM is used. The external data generation
script used in TRANSFORM
- // may result malformed rows, causing
ArrayIndexOutOfBoundsException, which is somewhat
- // hard to decipher.
- assert(
- row.numFields == columnBuilders.length,
- s"Row column number mismatch, expected ${output.size} columns, "
+
- s"but got ${row.numFields}." +
- s"\nRow content: $row")
-
- var i = 0
- totalSize = 0
- while (i < row.numFields) {
- columnBuilders(i).appendFrom(row, i)
- totalSize += columnBuilders(i).columnStats.sizeInBytes
- i += 1
- }
- rowCount += 1
- }
-
- sizeInBytesStats.add(totalSize)
- rowCountStats.add(rowCount)
-
- val stats = InternalRow.fromSeq(
- columnBuilders.flatMap(_.columnStats.collectedStatistics).toSeq)
- CachedBatch(rowCount, columnBuilders.map { builder =>
- JavaUtils.bufferToArray(builder.build())
- }, stats)
- }
-
- def hasNext: Boolean = rowIterator.hasNext
- }
+ val cb = if (cachedPlan.supportsColumnar) {
+ serializer.convertForCacheColumnar(cachedPlan.executeColumnar(),
+ cachedPlan.output,
+ storageLevel,
+ cachedPlan.conf)
+ } else {
+ serializer.convertForCache(cachedPlan.execute(),
+ cachedPlan.output,
+ storageLevel,
+ cachedPlan.conf)
+ }
+ val cached = cb.map { batch =>
+ sizeInBytesStats.add(batch.sizeInBytes)
+ rowCountStats.add(batch.numRows)
+ batch
}.persist(storageLevel)
-
cached.setName(cachedName)
cached
}
}
object InMemoryRelation {
+ private[this] var ser: Option[CachedBatchSerializer] = None
+ private[this] def getSerializer(sqlConf: SQLConf): CachedBatchSerializer =
synchronized {
+ if (ser.isEmpty) {
+ val serName = sqlConf.getConf(StaticSQLConf.SPARK_CACHE_SERIALIZER)
+ val serClass = Utils.classForName(serName)
+ val instance =
serClass.getConstructor().newInstance().asInstanceOf[CachedBatchSerializer]
+ ser = Some(instance)
+ }
+ ser.get
+ }
+
def apply(
- useCompression: Boolean,
- batchSize: Int,
+ storageLevel: StorageLevel,
+ qe: QueryExecution,
+ tableName: Option[String]): InMemoryRelation = {
+ val optimizedPlan = qe.optimizedPlan
+ val serializer = getSerializer(optimizedPlan.conf)
+ val child = if (serializer.supportsColumnarInput(optimizedPlan.output)) {
Review comment:
I picked row based input as a minimum requirement because the majority
of the time the output of the plan will be row based. I also wanted to avoid
unnecessary transitions from one data format to another. Each time one tries to
change the format of the data, row to column, column to row, or even column of
one type to column of another there is a cost involved. As a rule of thumb it
is ideal to reduce those transformations when ever possible. So in that respect
columnar input support is a performance optimization in the rare case that
columnar input is a possibility.
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