Github user abhishekagarwal87 commented on a diff in the pull request:
https://github.com/apache/storm/pull/1131#discussion_r55957034
--- Diff:
external/storm-kafka-client/src/main/java/org/apache/storm/kafka/spout/KafkaSpoutStreams.java
---
@@ -0,0 +1,142 @@
+/*
+ * 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.storm.kafka.spout;
+
+import org.apache.storm.spout.SpoutOutputCollector;
+import org.apache.storm.topology.OutputFieldsDeclarer;
+import org.apache.storm.tuple.Fields;
+import org.apache.storm.utils.Utils;
+
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Represents the output streams associated with each topic, and provides
a public API to
+ * declare output streams and emmit tuples, on the appropriate stream, for
all the topics specified.
+ */
+public class KafkaSpoutStreams implements Serializable {
+ private final Map<String, KafkaSpoutStream> topicToStream;
+
+ private KafkaSpoutStreams(Builder builder) {
+ this.topicToStream = builder.topicToStream;
+ }
+
+ /**
+ * @param topic the topic for which to get output fields
+ * @return the output fields declared
+ */
+ public Fields getOutputFields(String topic) {
+ if (topicToStream.containsKey(topic)) {
+ return topicToStream.get(topic).getOutputFields();
+ }
+ throw new IllegalStateException(this.getClass().getName() + " not
configured for topic: " + topic);
+ }
+
+ /**
+ * @param topic the topic to for which to get the stream id
+ * @return the id of the stream to where the tuples are emitted
+ */
+ public String getStreamId(String topic) {
+ if (topicToStream.containsKey(topic)) {
+ return topicToStream.get(topic).getStreamId();
+ }
+ throw new IllegalStateException(this.getClass().getName() + " not
configured for topic: " + topic);
+ }
+
+ /**
+ * @return list of topics subscribed and emitting tuples to a stream
as configured by {@link KafkaSpoutStream}
+ */
+ public List<String> getTopics() {
+ return new ArrayList<>(topicToStream.keySet());
+ }
+
+ void declareOutputFields(OutputFieldsDeclarer declarer) {
+ for (KafkaSpoutStream stream : topicToStream.values()) {
+ declarer.declareStream(stream.getStreamId(),
stream.getOutputFields());
+ }
+ }
+
+ void emit(SpoutOutputCollector collector, MessageId messageId) {
+ collector.emit(getStreamId(messageId.topic()),
messageId.getTuple(), messageId);
--- End diff --
older consumer didn't call the fetch again till the _waitingToEmit queue
became empty. And records were only stored in _waitingToEmit. Here however,
they are also stored as a part of message id. The message id in turn is stored
in two data structures -
1. pending map of spout - It has an upper ceiling of
topology.max.spout.pending * sizeof(message id) bytes
2. acked map - This stores the message ids that have been acked. It is
cleared on a time basis and doesn't have any upper ceiling on number of entries
per TopicPartition.
@hmcl @harshach Please let me know if above two are valid inferences.
Nonetheless, I am +1 on resolving this discussion later without blocking the
PR.
---
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.
---
