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https://issues.apache.org/jira/browse/FLINK-9913?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16576423#comment-16576423
]
ASF GitHub Bot commented on FLINK-9913:
---------------------------------------
pnowojski commented on a change in pull request #6417: [FLINK-9913][runtime]
Improve output serialization only once in RecordWriter
URL: https://github.com/apache/flink/pull/6417#discussion_r209289603
##########
File path:
flink-runtime/src/test/java/org/apache/flink/runtime/io/network/api/writer/RecordWriterTest.java
##########
@@ -377,6 +388,86 @@ public void testBroadcastEmitBufferIndependence() throws
Exception {
assertEquals("Buffer 2 shares the same reader index as buffer
1", 0, buffer2.getReaderIndex());
}
+ /**
+ * Tests that records are broadcast via {@link ChannelSelector} and
+ * {@link RecordWriter#emit(IOReadableWritable)}.
+ */
+ @Test
+ public void testEmitRecordWithBroadcastPartitioner() throws Exception {
+ emitRecordWithBroadcastPartitionerOrBroadcastEmitRecord(false);
+ }
+
+ /**
+ * Tests that records are broadcast via {@link
RecordWriter#broadcastEmit(IOReadableWritable)}.
+ */
+ @Test
+ public void testBroadcastEmitRecord() throws Exception {
+ emitRecordWithBroadcastPartitionerOrBroadcastEmitRecord(true);
+ }
+
+ /**
+ * The results of emitting records via BroadcastPartitioner or
broadcasting records directly are the same,
+ * that is all the target channels can receive the whole outputs.
+ *
+ * @param isBroadcastEmit whether using {@link
RecordWriter#broadcastEmit(IOReadableWritable)} or not
+ */
+ private void
emitRecordWithBroadcastPartitionerOrBroadcastEmitRecord(boolean
isBroadcastEmit) throws Exception {
+ final int numChannels = 4;
+ final int bufferSize = 32;
+ final int numValues = 8;
+ final int serializationLength = 4;
+
+ @SuppressWarnings("unchecked")
+ final Queue<BufferConsumer>[] queues = new Queue[numChannels];
+ for (int i = 0; i < numChannels; i++) {
+ queues[i] = new ArrayDeque<>();
+ }
+
+ final TestPooledBufferProvider bufferProvider = new
TestPooledBufferProvider(Integer.MAX_VALUE, bufferSize);
+ final ResultPartitionWriter partitionWriter = new
CollectingPartitionWriter(queues, bufferProvider);
+ final RecordWriter<SerializationTestType> writer = new
RecordWriter<>(partitionWriter, new Broadcast<>());
+ final RecordDeserializer<SerializationTestType> deserializer =
new SpillingAdaptiveSpanningRecordDeserializer<>(
+ new String[]{ tempFolder.getRoot().getAbsolutePath() });
+
+ final ArrayDeque<SerializationTestType> serializedRecords = new
ArrayDeque<>();
+ final Iterable<SerializationTestType> records =
Util.randomRecords(numValues, SerializationTestTypeFactory.INT);
+ for (SerializationTestType record : records) {
+ serializedRecords.add(record);
+
+ if (isBroadcastEmit) {
+ writer.broadcastEmit(record);
+ } else {
+ writer.emit(record);
+ }
+ }
+
+ final int requiredBuffers = numValues / (bufferSize / (4 +
serializationLength));
+ for (int i = 0; i < numChannels; i++) {
Review comment:
can you somehow extract common logic of this method and
`org.apache.flink.runtime.io.network.api.serialization.SpanningRecordSerializationTest#testSerializationRoundTrip(java.lang.Iterable<org.apache.flink.testutils.serialization.types.SerializationTestType>,
int,
org.apache.flink.runtime.io.network.api.serialization.RecordSerializer<org.apache.flink.testutils.serialization.types.SerializationTestType>,
org.apache.flink.runtime.io.network.api.serialization.RecordDeserializer<org.apache.flink.testutils.serialization.types.SerializationTestType>)`?
They share a lot of core.
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> Improve output serialization only once in RecordWriter
> ------------------------------------------------------
>
> Key: FLINK-9913
> URL: https://issues.apache.org/jira/browse/FLINK-9913
> Project: Flink
> Issue Type: Improvement
> Components: Network
> Affects Versions: 1.6.0
> Reporter: zhijiang
> Assignee: zhijiang
> Priority: Minor
> Labels: pull-request-available
> Fix For: 1.7.0
>
>
> Currently the {{RecordWriter}} emits output into multi channels via
> {{ChannelSelector}} or broadcasts output to all channels directly. Each
> channel has a separate {{RecordSerializer}} for serializing outputs, that
> means the output will be serialized as many times as the number of selected
> channels.
> As we know, data serialization is a high cost operation, so we can get good
> benefits by improving the serialization only once.
> I would suggest the following changes for realizing it.
> # Only one {{RecordSerializer}} is created in {{RecordWriter}} for all the
> channels.
> # The output is serialized into the intermediate data buffer only once for
> different channels.
> # The intermediate serialization results are copied into different
> {{BufferBuilder}}s for different channels.
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