KurtYoung commented on a change in pull request #8499: [FLINK-12575]
[table-planner-blink] Introduce planner rules to remove redundant shuffle and
collation
URL: https://github.com/apache/flink/pull/8499#discussion_r287198770
##########
File path:
flink-table/flink-table-planner-blink/src/main/scala/org/apache/flink/table/plan/nodes/physical/batch/BatchExecHashAggregate.scala
##########
@@ -94,6 +99,53 @@ class BatchExecHashAggregate(
isGlobal = true))
}
+ override def satisfyTraits(requiredTraitSet: RelTraitSet): RelNode = {
+ val requiredDistribution =
requiredTraitSet.getTrait(FlinkRelDistributionTraitDef.INSTANCE)
+ val canSatisfy = requiredDistribution.getType match {
+ case SINGLETON => grouping.length == 0
+ case HASH_DISTRIBUTED =>
+ val shuffleKeys = requiredDistribution.getKeys
+ val groupKeysList = ImmutableIntList.of(grouping.indices.toArray: _*)
+ if (requiredDistribution.requireStrict) {
+ shuffleKeys == groupKeysList
+ } else if (Util.startsWith(shuffleKeys, groupKeysList)) {
+ // If required distribution is not strict, Hash[a] can satisfy
Hash[a, b].
+ // so return true if shuffleKeys(Hash[a, b]) start with
groupKeys(Hash[a])
+ true
+ } else {
+ // If partialKey is enabled, try to use partial key to satisfy the
required distribution
+ val tableConfig = FlinkRelOptUtil.getTableConfigFromContext(this)
+ val partialKeyEnabled = tableConfig.getConf.getBoolean(
+ PlannerConfigOptions.SQL_OPTIMIZER_SHUFFLE_PARTIAL_KEY_ENABLED)
+ partialKeyEnabled && groupKeysList.containsAll(shuffleKeys)
+ }
+ case _ => false
+ }
+ if (!canSatisfy) {
+ return null
+ }
+
+ val inputRequiredDistribution = requiredDistribution.getType match {
+ case SINGLETON => requiredDistribution
+ case HASH_DISTRIBUTED =>
+ val shuffleKeys = requiredDistribution.getKeys
+ val groupKeysList = ImmutableIntList.of(grouping.indices.toArray: _*)
+ if (requiredDistribution.requireStrict) {
+ FlinkRelDistribution.hash(grouping, requireStrict = true)
+ } else if (Util.startsWith(shuffleKeys, groupKeysList)) {
+ // Hash[a] can satisfy Hash[a, b]
+ FlinkRelDistribution.hash(grouping, requireStrict = false)
+ } else {
+ // use partial key to satisfy the required distribution
+ FlinkRelDistribution.hash(shuffleKeys.map(grouping(_)).toArray,
requireStrict = false)
Review comment:
why `shuffleKeys.map(grouping(_))`?
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