[SPARK-24935][SQL][FOLLOWUP] support INIT -> UPDATE -> MERGE -> FINISH in Hive UDAF adapter

## What changes were proposed in this pull request?

This is a followup of https://github.com/apache/spark/pull/24144 . #24144 missed one case: when hash aggregate fallback to sort aggregate, the life cycle of UDAF is: INIT -> UPDATE -> MERGE -> FINISH.

However, not all Hive UDAF can support it. Hive UDAF knows the aggregation mode when creating the aggregation buffer, so that it can create different buffers for different inputs: the original data or the aggregation buffer. Please see an example in the [sketches library](7f9e76e9e0/src/main/java/com/yahoo/sketches/hive/cpc/DataToSketchUDAF.java (L107)). The buffer for UPDATE may not support MERGE.

This PR updates the Hive UDAF adapter in Spark to support INIT -> UPDATE -> MERGE -> FINISH, by turning it to  INIT -> UPDATE -> FINISH + IINIT -> MERGE -> FINISH.

## How was this patch tested?

a new test case

Closes #24459 from cloud-fan/hive-udaf.

Authored-by: Wenchen Fan <wenchen@databricks.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
This commit is contained in:
Wenchen Fan 2019-04-30 10:35:23 +08:00
parent 618d6bff71
commit 7432e7ded4
2 changed files with 65 additions and 29 deletions

View file

@ -304,6 +304,13 @@ private[hive] case class HiveGenericUDTF(
* - `wrap()`/`wrapperFor()`: from 3 to 1
* - `unwrap()`/`unwrapperFor()`: from 1 to 3
* - `GenericUDAFEvaluator.terminatePartial()`: from 2 to 3
*
* Note that, Hive UDAF is initialized with aggregate mode, and some specific Hive UDAFs can't
* mix UPDATE and MERGE actions during its life cycle. However, Spark may do UPDATE on a UDAF and
* then do MERGE, in case of hash aggregate falling back to sort aggregate. To work around this
* issue, we track the ability to do MERGE in the Hive UDAF aggregate buffer. If Spark does
* UPDATE then MERGE, we can detect it and re-create the aggregate buffer with a different
* aggregate mode.
*/
private[hive] case class HiveUDAFFunction(
name: String,
@ -312,7 +319,7 @@ private[hive] case class HiveUDAFFunction(
isUDAFBridgeRequired: Boolean = false,
mutableAggBufferOffset: Int = 0,
inputAggBufferOffset: Int = 0)
extends TypedImperativeAggregate[GenericUDAFEvaluator.AggregationBuffer]
extends TypedImperativeAggregate[HiveUDAFBuffer]
with HiveInspectors
with UserDefinedExpression {
@ -410,55 +417,70 @@ private[hive] case class HiveUDAFFunction(
// aggregate buffer. However, the Spark UDAF framework does not expose this information when
// creating the buffer. Here we return null, and create the buffer in `update` and `merge`
// on demand, so that we can know what input we are dealing with.
override def createAggregationBuffer(): AggregationBuffer = null
override def createAggregationBuffer(): HiveUDAFBuffer = null
@transient
private lazy val inputProjection = UnsafeProjection.create(children)
override def update(buffer: AggregationBuffer, input: InternalRow): AggregationBuffer = {
override def update(buffer: HiveUDAFBuffer, input: InternalRow): HiveUDAFBuffer = {
// The input is original data, we create buffer with the partial1 evaluator.
val nonNullBuffer = if (buffer == null) {
partial1HiveEvaluator.evaluator.getNewAggregationBuffer
HiveUDAFBuffer(partial1HiveEvaluator.evaluator.getNewAggregationBuffer, false)
} else {
buffer
}
assert(!nonNullBuffer.canDoMerge, "can not call `merge` then `update` on a Hive UDAF.")
partial1HiveEvaluator.evaluator.iterate(
nonNullBuffer, wrap(inputProjection(input), inputWrappers, cached, inputDataTypes))
nonNullBuffer.buf, wrap(inputProjection(input), inputWrappers, cached, inputDataTypes))
nonNullBuffer
}
override def merge(buffer: AggregationBuffer, input: AggregationBuffer): AggregationBuffer = {
override def merge(buffer: HiveUDAFBuffer, input: HiveUDAFBuffer): HiveUDAFBuffer = {
// The input is aggregate buffer, we create buffer with the final evaluator.
val nonNullBuffer = if (buffer == null) {
finalHiveEvaluator.evaluator.getNewAggregationBuffer
HiveUDAFBuffer(finalHiveEvaluator.evaluator.getNewAggregationBuffer, true)
} else {
buffer
}
// It's possible that we've called `update` of this Hive UDAF, and some specific Hive UDAF
// implementation can't mix the `update` and `merge` calls during its life cycle. To work
// around it, here we create a fresh buffer with final evaluator, and merge the existing buffer
// to it, and replace the existing buffer with it.
val mergeableBuf = if (!nonNullBuffer.canDoMerge) {
val newBuf = finalHiveEvaluator.evaluator.getNewAggregationBuffer
finalHiveEvaluator.evaluator.merge(
newBuf, partial1HiveEvaluator.evaluator.terminatePartial(nonNullBuffer.buf))
HiveUDAFBuffer(newBuf, true)
} else {
nonNullBuffer
}
// The 2nd argument of the Hive `GenericUDAFEvaluator.merge()` method is an input aggregation
// buffer in the 3rd format mentioned in the ScalaDoc of this class. Originally, Hive converts
// this `AggregationBuffer`s into this format before shuffling partial aggregation results, and
// calls `GenericUDAFEvaluator.terminatePartial()` to do the conversion.
finalHiveEvaluator.evaluator.merge(
nonNullBuffer, partial1HiveEvaluator.evaluator.terminatePartial(input))
nonNullBuffer
mergeableBuf.buf, partial1HiveEvaluator.evaluator.terminatePartial(input.buf))
mergeableBuf
}
override def eval(buffer: AggregationBuffer): Any = {
resultUnwrapper(finalHiveEvaluator.evaluator.terminate(buffer))
override def eval(buffer: HiveUDAFBuffer): Any = {
resultUnwrapper(finalHiveEvaluator.evaluator.terminate(buffer.buf))
}
override def serialize(buffer: AggregationBuffer): Array[Byte] = {
override def serialize(buffer: HiveUDAFBuffer): Array[Byte] = {
// Serializes an `AggregationBuffer` that holds partial aggregation results so that we can
// shuffle it for global aggregation later.
aggBufferSerDe.serialize(buffer)
aggBufferSerDe.serialize(buffer.buf)
}
override def deserialize(bytes: Array[Byte]): AggregationBuffer = {
override def deserialize(bytes: Array[Byte]): HiveUDAFBuffer = {
// Deserializes an `AggregationBuffer` from the shuffled partial aggregation phase to prepare
// for global aggregation by merging multiple partial aggregation results within a single group.
aggBufferSerDe.deserialize(bytes)
HiveUDAFBuffer(aggBufferSerDe.deserialize(bytes), false)
}
// Helper class used to de/serialize Hive UDAF `AggregationBuffer` objects
@ -506,3 +528,5 @@ private[hive] case class HiveUDAFFunction(
}
}
}
case class HiveUDAFBuffer(buf: AggregationBuffer, canDoMerge: Boolean)

View file

@ -28,10 +28,10 @@ import org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectIn
import org.apache.hadoop.hive.serde2.typeinfo.TypeInfo
import test.org.apache.spark.sql.MyDoubleAvg
import org.apache.spark.SparkException
import org.apache.spark.sql.{AnalysisException, QueryTest, Row}
import org.apache.spark.sql.execution.aggregate.ObjectHashAggregateExec
import org.apache.spark.sql.hive.test.TestHiveSingleton
import org.apache.spark.sql.internal.SQLConf
import org.apache.spark.sql.test.SQLTestUtils
class HiveUDAFSuite extends QueryTest with TestHiveSingleton with SQLTestUtils {
@ -94,21 +94,33 @@ class HiveUDAFSuite extends QueryTest with TestHiveSingleton with SQLTestUtils {
))
}
test("customized Hive UDAF with two aggregation buffers") {
val df = sql("SELECT key % 2, mock2(value) FROM t GROUP BY key % 2")
test("SPARK-24935: customized Hive UDAF with two aggregation buffers") {
withTempView("v") {
spark.range(100).createTempView("v")
val df = sql("SELECT id % 2, mock2(id) FROM v GROUP BY id % 2")
val aggs = df.queryExecution.executedPlan.collect {
case agg: ObjectHashAggregateExec => agg
val aggs = df.queryExecution.executedPlan.collect {
case agg: ObjectHashAggregateExec => agg
}
// There should be two aggregate operators, one for partial aggregation, and the other for
// global aggregation.
assert(aggs.length == 2)
withSQLConf(SQLConf.OBJECT_AGG_SORT_BASED_FALLBACK_THRESHOLD.key -> "1") {
checkAnswer(df, Seq(
Row(0, Row(50, 0)),
Row(1, Row(50, 0))
))
}
withSQLConf(SQLConf.OBJECT_AGG_SORT_BASED_FALLBACK_THRESHOLD.key -> "100") {
checkAnswer(df, Seq(
Row(0, Row(50, 0)),
Row(1, Row(50, 0))
))
}
}
// There should be two aggregate operators, one for partial aggregation, and the other for
// global aggregation.
assert(aggs.length == 2)
checkAnswer(df, Seq(
Row(0, Row(1, 1)),
Row(1, Row(1, 1))
))
}
test("call JAVA UDAF") {