[GitHub] [incubator-doris] jackwener commented on a diff in pull request #8861: [feature-wip](statistics) step4: collect statistics by implementing statistics tasks

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

jackwener commented on code in PR #8861:
URL: https://github.com/apache/incubator-doris/pull/8861#discussion_r880414867


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fe/fe-core/src/main/java/org/apache/doris/statistics/PartitionStats.java:
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@@ -0,0 +1,129 @@
+// 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.doris.statistics;
+
+import org.apache.doris.catalog.Type;
+import org.apache.doris.common.AnalysisException;
+import org.apache.doris.common.util.Util;
+
+import com.google.common.collect.Lists;
+import com.google.common.collect.Maps;
+
+import java.util.List;
+import java.util.Map;
+import java.util.function.Predicate;
+
+
+/**
+ * There are the statistics of partition.
+ * The partition stats are mainly used to provide input for the Optimizer's cost model.
+ * The description of partition stats are following:
+ *     - @rowCount: The row count of partition.
+ *     - @dataSize: The data size of partition.
+ *     - @nameToColumnStats: <@String columnName, @ColumnStats columnStats>
+ *
+ * <p>Each column in the Table will have corresponding @ColumnStats.
+ * Those @ColumnStats are recorded in @nameToColumnStats form of MAP.
+ * This facilitates the optimizer to quickly find the corresponding:
+ *     - @ColumnStats: based on the column name.
+ *     - @rowCount: The row count of partition.
+ *     - @dataSize: The data size of partition.
+ *
+ * <p>The granularity of the statistics is whole partition.
+ * For example: "@rowCount = 1000" means that the row count is 1000 in the whole partition.
+ */
+public class PartitionStats {
+
+    public static final StatsType DATA_SIZE = StatsType.DATA_SIZE;
+    public static final StatsType ROW_COUNT = StatsType.ROW_COUNT;
+
+    private static final Predicate<Long> DESIRED_ROW_COUNT_PRED = (v) -> v >= -1L;
+    private static final Predicate<Long> DESIRED_DATA_SIZE_PRED = (v) -> v >= -1L;
+
+    private long rowCount = -1;
+    private long dataSize = -1;
+    private final Map<String, ColumnStats> nameToColumnStats = Maps.newConcurrentMap();
+
+    /**
+     * Update the partition stats.
+     *
+     * @param statsTypeToValue the map of stats type to value
+     * @throws AnalysisException if the stats value is not valid
+     */
+    public void updatePartitionStats(Map<StatsType, String> statsTypeToValue) throws AnalysisException {
+        for (Map.Entry<StatsType, String> entry : statsTypeToValue.entrySet()) {

Review Comment:
   I suggest use `statsTypeToValue.entrySet().forEach()` which is easier to read



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