[GitHub] [hive] asolimando commented on a diff in pull request #3339: HIVE-26277: Add unit tests for ColumnStatsAggregator classes

[GitBox <gi...@apache.org>]

asolimando commented on code in PR #3339:
URL: https://github.com/apache/hive/pull/3339#discussion_r969673443


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standalone-metastore/metastore-server/src/test/java/org/apache/hadoop/hive/metastore/columnstats/aggr/DateColumnStatsAggregatorTest.java:
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@@ -0,0 +1,279 @@
+/*
+ * 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.hadoop.hive.metastore.columnstats.aggr;
+
+import org.apache.hadoop.hive.metastore.TableType;
+import org.apache.hadoop.hive.metastore.annotation.MetastoreUnitTest;
+import org.apache.hadoop.hive.metastore.api.ColumnStatisticsData;
+import org.apache.hadoop.hive.metastore.api.ColumnStatisticsObj;
+import org.apache.hadoop.hive.metastore.api.Date;
+import org.apache.hadoop.hive.metastore.api.FieldSchema;
+import org.apache.hadoop.hive.metastore.api.MetaException;
+import org.apache.hadoop.hive.metastore.api.Table;
+import org.apache.hadoop.hive.metastore.columnstats.ColStatsBuilder;
+import org.apache.hadoop.hive.metastore.utils.MetaStoreServerUtils.ColStatsObjWithSourceInfo;
+import org.junit.Assert;
+import org.junit.Test;
+import org.junit.experimental.categories.Category;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+import static org.apache.hadoop.hive.metastore.StatisticsTestUtils.createStatsWithInfo;
+
+@Category(MetastoreUnitTest.class)
+public class DateColumnStatsAggregatorTest {
+
+  private static final Table TABLE = new Table("dummy", "db", "hive", 0, 0,
+      0, null, null, Collections.emptyMap(), null, null,
+      TableType.MANAGED_TABLE.toString());
+  private static final FieldSchema COL = new FieldSchema("col", "int", "");
+
+  private static final Date DATE_1 = new Date(1);
+  private static final Date DATE_2 = new Date(2);
+  private static final Date DATE_3 = new Date(3);
+  private static final Date DATE_4 = new Date(4);
+  private static final Date DATE_5 = new Date(5);
+  private static final Date DATE_6 = new Date(6);
+  private static final Date DATE_7 = new Date(7);
+  private static final Date DATE_8 = new Date(8);
+  private static final Date DATE_9 = new Date(9);
+
+  @Test
+  public void testAggregateSingleStat() throws MetaException {
+    List<String> partitions = Collections.singletonList("part1");
+
+    ColumnStatisticsData data1 = new ColStatsBuilder<>(Date.class).numNulls(1).numDVs(2).low(DATE_1).high(DATE_4)
+        .hll(DATE_1.getDaysSinceEpoch(), DATE_4.getDaysSinceEpoch()).build();
+    List<ColStatsObjWithSourceInfo> statsList =
+        Collections.singletonList(createStatsWithInfo(data1, TABLE, COL, partitions.get(0)));
+
+    DateColumnStatsAggregator aggregator = new DateColumnStatsAggregator();
+    ColumnStatisticsObj computedStatsObj = aggregator.aggregate(statsList, partitions, true);
+
+    Assert.assertEquals(data1, computedStatsObj.getStatsData());
+  }
+
+  @Test
+  public void testAggregateSingleStatWhenNullValues() throws MetaException {
+    List<String> partitions = Collections.singletonList("part1");
+
+    ColumnStatisticsData data1 = new ColStatsBuilder<>(Date.class).numNulls(1).numDVs(2).build();
+    List<ColStatsObjWithSourceInfo> statsList =
+        Collections.singletonList(createStatsWithInfo(data1, TABLE, COL, partitions.get(0)));
+
+    DateColumnStatsAggregator aggregator = new DateColumnStatsAggregator();
+    ColumnStatisticsObj computedStatsObj = aggregator.aggregate(statsList, partitions, true);
+    Assert.assertEquals(data1, computedStatsObj.getStatsData());
+
+    aggregator.useDensityFunctionForNDVEstimation = true;
+    computedStatsObj = aggregator.aggregate(statsList, partitions, true);
+    Assert.assertEquals(data1, computedStatsObj.getStatsData());
+
+    aggregator.useDensityFunctionForNDVEstimation = false;
+    aggregator.ndvTuner = 1;
+    // ndv tuner does not have any effect because min numDVs and max numDVs coincide (we have a single stats)
+    computedStatsObj = aggregator.aggregate(statsList, partitions, true);
+    Assert.assertEquals(data1, computedStatsObj.getStatsData());
+  }
+
+  @Test
+  public void testAggregateMultipleStatsWhenSomeNullValues() throws MetaException {
+    List<String> partitions = Arrays.asList("part1", "part2");
+
+    long[] values1 = { DATE_1.getDaysSinceEpoch(), DATE_2.getDaysSinceEpoch() };
+    ColumnStatisticsData data1 = new ColStatsBuilder<>(Date.class).numNulls(1).numDVs(2)
+        .low(DATE_1).high(DATE_2).hll(values1).build();
+    ColumnStatisticsData data2 = new ColStatsBuilder<>(Date.class).numNulls(2).numDVs(3).build();
+
+    List<ColStatsObjWithSourceInfo> statsList = Arrays.asList(createStatsWithInfo(data1, TABLE, COL, partitions.get(0)),
+        createStatsWithInfo(data2, TABLE, COL, partitions.get(1)));
+
+    DateColumnStatsAggregator aggregator = new DateColumnStatsAggregator();
+
+    ColumnStatisticsObj computedStatsObj = aggregator.aggregate(statsList, partitions, true);
+    ColumnStatisticsData expectedStats = new ColStatsBuilder<>(Date.class).numNulls(3).numDVs(3)
+        .low(DATE_1).high(DATE_2).hll(values1).build();
+    Assert.assertEquals(expectedStats, computedStatsObj.getStatsData());
+
+    aggregator.useDensityFunctionForNDVEstimation = true;
+    computedStatsObj = aggregator.aggregate(statsList, partitions, true);
+    expectedStats = new ColStatsBuilder<>(Date.class).numNulls(3).numDVs(4)
+        .low(DATE_1).high(DATE_2).hll(values1).build();
+    Assert.assertEquals(expectedStats, computedStatsObj.getStatsData());
+
+    aggregator.useDensityFunctionForNDVEstimation = false;
+    aggregator.ndvTuner = 1;
+    computedStatsObj = aggregator.aggregate(statsList, partitions, true);
+    expectedStats = new ColStatsBuilder<>(Date.class).numNulls(3).numDVs(5)
+        .low(DATE_1).high(DATE_2).hll(values1).build();
+    Assert.assertEquals(expectedStats, computedStatsObj.getStatsData());
+  }
+
+  @Test
+  public void testAggregateMultiStatsWhenAllAvailable() throws MetaException {
+    List<String> partitions = Arrays.asList("part1", "part2", "part3");
+
+    long[] values1 = { DATE_1.getDaysSinceEpoch(), DATE_2.getDaysSinceEpoch(), DATE_3.getDaysSinceEpoch() };
+    ColumnStatisticsData data1 = new ColStatsBuilder<>(Date.class).numNulls(1).numDVs(3)
+        .low(DATE_1).high(DATE_3).hll(values1).build();
+
+    long[] values2 = { DATE_3.getDaysSinceEpoch(), DATE_4.getDaysSinceEpoch(), DATE_5.getDaysSinceEpoch() };
+    ColumnStatisticsData data2 = new ColStatsBuilder<>(Date.class).numNulls(2).numDVs(3)
+        .low(DATE_3).high(DATE_5).hll(values2).build();
+
+    long[] values3 = { DATE_6.getDaysSinceEpoch(), DATE_7.getDaysSinceEpoch() };
+    ColumnStatisticsData data3 = new ColStatsBuilder<>(Date.class).numNulls(3).numDVs(2)
+        .low(DATE_6).high(DATE_7).hll(values3).build();
+
+    List<ColStatsObjWithSourceInfo> statsList = Arrays.asList(createStatsWithInfo(data1, TABLE, COL, partitions.get(0)),
+        createStatsWithInfo(data2, TABLE, COL, partitions.get(1)), createStatsWithInfo(data3, TABLE, COL, partitions.get(2)));
+
+    DateColumnStatsAggregator aggregator = new DateColumnStatsAggregator();
+    ColumnStatisticsObj computedStatsObj = aggregator.aggregate(statsList, partitions, true);
+
+    // the aggregation does not update hll, only numNDVs is, it keeps the first hll
+    ColumnStatisticsData expectedStats = new ColStatsBuilder<>(Date.class).numNulls(6).numDVs(7)
+        .low(DATE_1).high(DATE_7).hll(values1).build();
+
+    Assert.assertEquals(expectedStats, computedStatsObj.getStatsData());
+  }
+
+  @Test
+  public void testAggregateMultiStatsWhenUnmergeableBitVectors() throws MetaException {
+    List<String> partitions = Arrays.asList("part1", "part2", "part3");
+
+    long[] values1 = { DATE_1.getDaysSinceEpoch(), DATE_2.getDaysSinceEpoch(), DATE_3.getDaysSinceEpoch() };
+    ColumnStatisticsData data1 = new ColStatsBuilder<>(Date.class).numNulls(1).numDVs(3)
+        .low(DATE_1).high(DATE_3).fmSketch(values1).build();
+    long[] values2 = { DATE_3.getDaysSinceEpoch(), DATE_4.getDaysSinceEpoch(), DATE_5.getDaysSinceEpoch() };
+    ColumnStatisticsData data2 = new ColStatsBuilder<>(Date.class).numNulls(2).numDVs(3)
+        .low(DATE_3).high(DATE_5).hll(values2).build();
+    long[] values3 = { DATE_1.getDaysSinceEpoch(), DATE_2.getDaysSinceEpoch(), DATE_6.getDaysSinceEpoch(),
+        DATE_8.getDaysSinceEpoch() };
+    ColumnStatisticsData data3 = new ColStatsBuilder<>(Date.class).numNulls(3).numDVs(4)
+        .low(DATE_1).high(DATE_8).hll(values3).build();
+
+    List<ColStatsObjWithSourceInfo> statsList = Arrays.asList(createStatsWithInfo(data1, TABLE, COL, partitions.get(0)),
+        createStatsWithInfo(data2, TABLE, COL, partitions.get(1)), createStatsWithInfo(data3, TABLE, COL, partitions.get(2)));
+
+    DateColumnStatsAggregator aggregator = new DateColumnStatsAggregator();
+
+    ColumnStatisticsObj computedStatsObj = aggregator.aggregate(statsList, partitions, true);
+    // the aggregation does not update the bitvector, only numDVs is, it keeps the first bitvector;

Review Comment:
   It is totally random, but I am just documenting what the existing code is doing. The bitvector itself is just used to derive the updated numDV, which gets updated here, so probably the original author did not consider interesting updating the bitvector here.



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