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https://issues.apache.org/jira/browse/STORM-1075?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15012870#comment-15012870
]
ASF GitHub Bot commented on STORM-1075:
---------------------------------------
Github user satishd commented on a diff in the pull request:
https://github.com/apache/storm/pull/827#discussion_r45302419
--- Diff:
external/storm-cassandra/src/main/java/org/apache/storm/cassandra/Murmur3StreamGrouping.java
---
@@ -0,0 +1,89 @@
+/**
+ * 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.cassandra;
+
+import backtype.storm.generated.GlobalStreamId;
+import backtype.storm.grouping.CustomStreamGrouping;
+import backtype.storm.task.WorkerTopologyContext;
+import backtype.storm.topology.FailedException;
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.collect.Lists;
+import com.google.common.hash.Hashing;
+
+import java.io.ByteArrayOutputStream;
+import java.io.DataOutputStream;
+import java.io.IOException;
+import java.util.List;
+
+/**
+ *
+ * Simple {@link backtype.storm.grouping.CustomStreamGrouping} that uses
Murmur3 algorithm to choose the target task of a tuple.
+ *
+ * This stream grouping may be used to optimise writes to Apache Cassandra.
+ */
+public class Murmur3StreamGrouping implements CustomStreamGrouping {
--- End diff --
It is better to take field names instead of indexes. You can get output
declared fields by using the API:
WorkerTopologyContext#getComponentOutputFields(GlobalStreamId id) in prepare
method and store the respective indexes like below.
public void prepare(WorkerTopologyContext workerTopologyContext,
GlobalStreamId globalStreamId, List<Integer> targetTasks) {
this.targetTasks = targetTasks;
partitionKeyIndexes = new ArrayList<>();
Fields componentOutputFields =
workerTopologyContext.getComponentOutputFields(globalStreamId);
for (String partitionKeyName : partitionKeyNames) {
partitionKeyIndexes.add(componentOutputFields.fieldIndex(partitionKeyName));
}
}
> Storm Cassandra connector
> -------------------------
>
> Key: STORM-1075
> URL: https://issues.apache.org/jira/browse/STORM-1075
> Project: Apache Storm
> Issue Type: Improvement
> Components: storm-core
> Reporter: Sriharsha Chintalapani
> Assignee: Satish Duggana
>
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