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Posted to dev@apex.apache.org by "ASF GitHub Bot (JIRA)" <ji...@apache.org> on 2016/03/25 08:17:25 UTC
[jira] [Commented] (APEXMALHAR-1965) Create a WAL in Malhar
[ https://issues.apache.org/jira/browse/APEXMALHAR-1965?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15211540#comment-15211540 ]
ASF GitHub Bot commented on APEXMALHAR-1965:
--------------------------------------------
Github user chandnisingh commented on a diff in the pull request:
https://github.com/apache/incubator-apex-malhar/pull/204#discussion_r57424510
--- Diff: library/src/main/java/org/apache/apex/malhar/lib/wal/FSWal.java ---
@@ -0,0 +1,178 @@
+/**
+ * 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.apex.malhar.lib.wal;
+
+import java.io.DataInputStream;
+import java.io.DataOutputStream;
+import java.io.EOFException;
+import java.io.IOException;
+
+import org.apache.hadoop.fs.FSDataOutputStream;
+
+import com.google.common.base.Preconditions;
+
+import com.datatorrent.lib.fileaccess.FileAccess;
+
+/**
+ * WAL implementation which allows writing entries to single file.
+ * the pointer type is the offset in the file. The entry is serialized into byte array and
+ * first length of the entry is written followed by the serialized bytes.
+ * @param <T>
+ */
+public class FSWal<T> implements WAL<T, Long>
+{
+ transient long bucketKey;
+ private transient String name;
+ private transient FileAccess fa;
--- End diff --
These fields are all transient. Is this intended?
> Create a WAL in Malhar
> ----------------------
>
> Key: APEXMALHAR-1965
> URL: https://issues.apache.org/jira/browse/APEXMALHAR-1965
> Project: Apache Apex Malhar
> Issue Type: Task
> Reporter: Chandni Singh
> Assignee: Tushar Gosavi
>
> In Malhar we have an IdempotentStorageManager which we use like a Write Ahead Logger. There have been some other places where we have created a different flavor of Write Ahead Logger.
> We need to find overlap between all these flavors and create a common Write Ahead Logger for use in Apex core and Apex malhar.
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