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https://issues.apache.org/jira/browse/TAJO-1112?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14170791#comment-14170791
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ASF GitHub Bot commented on TAJO-1112:
--------------------------------------
Github user jihoonson commented on a diff in the pull request:
https://github.com/apache/tajo/pull/200#discussion_r18821699
--- Diff:
tajo-catalog/tajo-catalog-common/src/main/java/org/apache/tajo/catalog/statistics/EquiDepthHistogram.java
---
@@ -0,0 +1,95 @@
+/**
+ * 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.tajo.catalog.statistics;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+import org.apache.tajo.catalog.proto.CatalogProtos.HistogramProto;
+import org.apache.tajo.util.TUtil;
+
+public class EquiDepthHistogram extends Histogram {
+
+ public EquiDepthHistogram() {
+ super();
+ }
+
+ public EquiDepthHistogram(HistogramProto proto) {
+ super(proto);
+ }
+
+ @Override
+ public boolean construct(List<Double> samples) {
+ int numBuckets = samples.size() > DEFAULT_MAX_BUCKETS ?
DEFAULT_MAX_BUCKETS : samples.size();
+ return construct(samples, numBuckets);
+ }
+
+ /**
+ * An EquiDepth histogram is constructed by dividing the data points
into buckets of equal frequencies (as equal as
+ * possible).
+ *
+ * Note that, this function, which allows the specification of the
(maximum) number of buckets, should be called
+ * directly only in the unit tests. In non-test cases, the
construct(samples) version above should be used.
+ */
+ public boolean construct(List<Double> srcSamples, int numBuckets) {
+ isReady = false;
+ buckets = TUtil.newList();
+
+ ArrayList<Double> samples = new ArrayList<Double>(srcSamples); //
sorted samples
+ Collections.sort(samples);
+
+ int averageFrequency = Math.round((float) samples.size() / numBuckets);
+ int bFrequency;
+ int bMinIndex = 0, bMaxIndex;
+ Double bMin, bMax;
+
+ for (int i = 0; i < numBuckets && bMinIndex < samples.size(); i++) {
+ bMin = samples.get(bMinIndex);
+ bFrequency = averageFrequency;
+ bMaxIndex = bMinIndex + averageFrequency - 1;
+
+ if (bMaxIndex > samples.size() - 1) {
+ bMaxIndex = samples.size() - 1;
+ bFrequency = bMaxIndex - bMinIndex + 1;
+ }
+
+ while (bMaxIndex + 1 < samples.size() &&
samples.get(bMaxIndex).equals(samples.get(bMaxIndex + 1))) {
+ bMaxIndex++;
+ bFrequency++;
+ }
+ bMax = samples.get(bMaxIndex);
+ bMinIndex = bMaxIndex + 1;
+ buckets.add(new HistogramBucket(bMin, bMax, bFrequency));
+ }
+
+ if (bMinIndex < samples.size()) {
+ int lastBucket = buckets.size() - 1;
+ int additionalFrequency = samples.size() - bMinIndex;
+
buckets.get(lastBucket).setFrequency(buckets.get(lastBucket).getFrequency() +
additionalFrequency);
+ buckets.get(lastBucket).setMax(samples.get(samples.size() - 1));
+ }
+
+ samples.clear();
+ isReady = true;
+ lastAnalyzed = System.currentTimeMillis();
--- End diff --
You need to use org.apache.hadoop.yarn.util.Clock.
You can refer SubQuery.setStartTime().
> Implement histogram interface and a candidate histogram
> -------------------------------------------------------
>
> Key: TAJO-1112
> URL: https://issues.apache.org/jira/browse/TAJO-1112
> Project: Tajo
> Issue Type: Sub-task
> Reporter: Long Mvh
> Assignee: Long Mvh
>
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