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https://issues.apache.org/jira/browse/ACCUMULO-3602?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14392032#comment-14392032
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ASF GitHub Bot commented on ACCUMULO-3602:
------------------------------------------
Github user joshelser commented on a diff in the pull request:
https://github.com/apache/accumulo/pull/25#discussion_r27629581
--- Diff:
core/src/main/java/org/apache/accumulo/core/client/mapreduce/BatchInputSplit.java
---
@@ -0,0 +1,151 @@
+/*
+ * 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.accumulo.core.client.mapreduce;
+
+import java.io.DataInput;
+import java.io.DataOutput;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+
+import org.apache.accumulo.core.data.Key;
+import org.apache.accumulo.core.data.PartialKey;
+import org.apache.accumulo.core.data.Range;
+
+/**
+ * The Class BatchInputSplit. Encapsulates a set of Accumulo ranges on a
single tablet for use in Map Reduce jobs.
+ * Can contain several Ranges per split.
+ */
+public class BatchInputSplit extends AccumuloInputSplit {
+ private Collection<Range> ranges;
+ private int scanThreads;
+
+ public BatchInputSplit() {
+ ranges = Collections.emptyList();
+ }
+
+ public BatchInputSplit(BatchInputSplit split) throws IOException {
+ super(split);
+ this.setRanges(split.getRanges());
+ }
+
+ protected BatchInputSplit(String table, String tableId,
Collection<Range> ranges, String[] locations) {
+ super(table, tableId, locations);
+ this.ranges = ranges;
+ }
+
+ public float getProgress(Key currentKey) {
+ if (currentKey == null)
+ return 0f;
+ for (Range range : ranges) {
--- End diff --
Of course, then I think of something. Perhaps keep a sum of the progress
over each Range and then return the average across the progress of each Range.
It's not guaranteed to be right since we may never get this method called with
each Range, but it might be close enough. The important part is ensuring that
this number will be increasing.
> BatchScanner optimization for AccumuloInputFormat
> -------------------------------------------------
>
> Key: ACCUMULO-3602
> URL: https://issues.apache.org/jira/browse/ACCUMULO-3602
> Project: Accumulo
> Issue Type: Improvement
> Components: client
> Affects Versions: 1.6.1, 1.6.2
> Reporter: Eugene Cheipesh
> Assignee: Eugene Cheipesh
> Labels: performance
> Fix For: 1.7.0
>
>
> Currently {{AccumuloInputFormat}} produces a split for reach {{Range}}
> specified in the configuration. Some table indexing schemes, for instance
> z-order geospacial index, produce large number of small ranges resulting in
> large number of splits. This is specifically a concern when using
> {{AccumuloInputFormat}} as a source for Spark RDD where each Split is mapped
> to an RDD partition.
> Large number of small RDD partitions leads to poor parallism on read and high
> overhead on processing. A desirable alternative is to group ranges by tablet
> into a single split and use {{BatchScanner}} to produce the records. Grouping
> by tablets is useful because it represents Accumulos attempt to distributed
> stored records and can be influance by the user through table splits.
> The grouping functionality already exists in the internal {{TabletLocator}}
> class.
> Current proposal is to modify {{AbstractInputFormat}} such that it generates
> either {{RangeInputSplit}} or {{MultiRangeInputSplit}} based on a new setting
> in {{InputConfigurator}}. {{AccumuloInputFormat}} would then be able to
> inspect the type of the split and instantiate an appropriate reader.
> The functinality of {{TabletLocator}} should be exposed as a public API in
> 1.7 as it is useful for optimizations.
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