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https://issues.apache.org/jira/browse/FLINK-6888?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16046320#comment-16046320
]
ASF GitHub Bot commented on FLINK-6888:
---------------------------------------
Github user sunjincheng121 commented on a diff in the pull request:
https://github.com/apache/flink/pull/4105#discussion_r121324222
--- Diff:
flink-libraries/flink-table/src/main/scala/org/apache/flink/table/functions/utils/AggSqlFunction.scala
---
@@ -37,24 +36,26 @@ import
org.apache.flink.table.functions.utils.UserDefinedFunctionUtils._
* @param name function name (used by SQL parser)
* @param aggregateFunction aggregate function to be called
* @param returnType the type information of returned value
+ * @param accType the type information of the accumulator
* @param typeFactory type factory for converting Flink's between
Calcite's types
*/
class AggSqlFunction(
name: String,
aggregateFunction: AggregateFunction[_, _],
- returnType: TypeInformation[_],
+ val returnType: TypeInformation[_],
+ val accType: TypeInformation[_],
typeFactory: FlinkTypeFactory,
requiresOver: Boolean)
- extends SqlUserDefinedAggFunction(
+ extends SqlAggFunction(
--- End diff --
Why we need change `SqlUserDefinedAggFunction` to `SqlAggFunction`. Is
there some reasons? If so, please explain more about.
If not so, I suggest keeping using `SqlUserDefinedAggFunction`. Because
`SqlUserDefinedAggFunction` is provided by Calcite which related the UDAG, in
order to adapt to Calcite changes I recommend keeping using
`SqlUserDefinedAggFunction`. (Although the `SqlUserDefinedAggFunction` of
calcite is covered by the current flink.).
> Can not determine TypeInformation of ACC type of AggregateFunction when ACC
> is a Scala case/tuple class
> -------------------------------------------------------------------------------------------------------
>
> Key: FLINK-6888
> URL: https://issues.apache.org/jira/browse/FLINK-6888
> Project: Flink
> Issue Type: Bug
> Components: Table API & SQL
> Reporter: Jark Wu
> Assignee: Jark Wu
> Fix For: 1.4.0
>
>
> Currently the {{ACC}} TypeInformation of
> {{org.apache.flink.table.functions.AggregateFunction[T, ACC]}} is extracted
> using {{TypeInformation.of(Class)}}. When {{ACC}} is a Scala case class or
> tuple class, the TypeInformation will fall back to {{GenericType}} which
> result in bad performance when state de/serialization.
> I suggest to extract the ACC TypeInformation when called
> {{TableEnvironment.registerFunction()}}.
> Here is an example:
> {code}
> case class Accumulator(sum: Long, count: Long)
> class MyAgg extends AggregateFunction[Long, Accumulator] {
> //Overloaded accumulate method
> def accumulate(acc: Accumulator, value: Long): Unit = {
> }
> override def createAccumulator(): Accumulator = Accumulator(0, 0)
> override def getValue(accumulator: Accumulator): Long = 1
> }
> {code}
> The {{Accumulator}} will be recognized as {{GenericType<Accumulator>}}.
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