Github user cloud-fan commented on a diff in the pull request:
https://github.com/apache/spark/pull/12612#discussion_r60942830
--- Diff: core/src/main/scala/org/apache/spark/NewAccumulator.scala ---
@@ -0,0 +1,356 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.spark
+
+import java.{lang => jl}
+import java.io.{ObjectInputStream, ObjectOutputStream}
+import java.util.concurrent.atomic.AtomicLong
+import javax.annotation.concurrent.GuardedBy
+
+import org.apache.spark.scheduler.AccumulableInfo
+import org.apache.spark.util.Utils
+
+
+private[spark] case class AccumulatorMetadata(
+ id: Long,
+ name: Option[String],
+ countFailedValues: Boolean) extends Serializable
+
+trait UpdatedValue extends Serializable
--- End diff --
cc @rxin , I didn't send the accumulator back for a serialization problem.
Basically when we send accumulator from driver to executors, we don't want
to send its current value(think about list accumulator, we definitely don't
wanna send the current list to executors.).
But when we send accumulator from executors to driver, we do need to send
the current value.
One possible solution is to have 2 local variables for each accumulator,
one for driver, one for executors. But it's a lot of trouble when accumulators
have complex intermedia type, e.g. average accumulator. So I end up with this
apporach.
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at [email protected] or file a JIRA ticket
with INFRA.
---
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
