Github user amansinha100 commented on a diff in the pull request:
https://github.com/apache/drill/pull/637#discussion_r86376128
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/store/parquet/stat/ParquetMetaStatCollector.java
---
@@ -0,0 +1,146 @@
+/**
+ * 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.drill.exec.store.parquet.stat;
+
+import org.apache.drill.common.expression.SchemaPath;
+import org.apache.drill.common.types.TypeProtos;
+import org.apache.drill.common.types.Types;
+import org.apache.drill.exec.store.parquet.Metadata;
+import org.apache.drill.exec.store.parquet.ParquetGroupScan;
+import org.apache.parquet.column.statistics.BinaryStatistics;
+import org.apache.parquet.column.statistics.DoubleStatistics;
+import org.apache.parquet.column.statistics.FloatStatistics;
+import org.apache.parquet.column.statistics.IntStatistics;
+import org.apache.parquet.column.statistics.LongStatistics;
+import org.apache.parquet.column.statistics.Statistics;
+import org.apache.parquet.schema.OriginalType;
+import org.apache.parquet.schema.PrimitiveType;
+import org.joda.time.DateTimeConstants;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+public class ParquetMetaStatCollector implements ColumnStatCollector{
+ private final Metadata.ParquetTableMetadataBase parquetTableMetadata;
+ private final List<? extends Metadata.ColumnMetadata>
columnMetadataList;
+ final Map<String, String> implicitColValues;
+
+ public ParquetMetaStatCollector(Metadata.ParquetTableMetadataBase
parquetTableMetadata, List<? extends Metadata.ColumnMetadata>
columnMetadataList, Map<String, String> implicitColValues) {
+ this.parquetTableMetadata = parquetTableMetadata;
+ this.columnMetadataList = columnMetadataList;
+ this.implicitColValues = implicitColValues;
+ }
+
+ @Override
+ public Map<SchemaPath, ColumnStatistics> collectColStat(Set<SchemaPath>
fields) {
+ // map from column to ColumnMetadata
+ final Map<SchemaPath, Metadata.ColumnMetadata> columnMetadataMap = new
HashMap<>();
+
+ // map from column name to column statistics.
+ final Map<SchemaPath, ColumnStatistics> statMap = new HashMap<>();
+
+ for (final Metadata.ColumnMetadata columnMetadata :
columnMetadataList) {
+ SchemaPath schemaPath =
SchemaPath.getCompoundPath(columnMetadata.getName());
+ columnMetadataMap.put(schemaPath, columnMetadata);
+ }
+
+ for (final SchemaPath schemaPath : fields) {
+ final PrimitiveType.PrimitiveTypeName primitiveType;
+ final OriginalType originalType;
+
+ final Metadata.ColumnMetadata columnMetadata =
columnMetadataMap.get(schemaPath);
+
+ if (columnMetadata != null) {
+ final Object min = columnMetadata.getMinValue();
+ final Object max = columnMetadata.getMaxValue();
+ final Long numNull = columnMetadata.getNulls();
+
+ primitiveType =
this.parquetTableMetadata.getPrimitiveType(columnMetadata.getName());
+ originalType =
this.parquetTableMetadata.getOriginalType(columnMetadata.getName());
+ final Integer repetitionLevel =
this.parquetTableMetadata.getRepetitionLevel(columnMetadata.getName());
+
+ statMap.put(schemaPath, getStat(min, max, numNull, primitiveType,
originalType, repetitionLevel));
+ } else {
+ final String columnName = schemaPath.getRootSegment().getPath();
+ if (implicitColValues.containsKey(columnName)) {
--- End diff --
It is not obvious why implicit column stats are collected as part of
ParquetMetaStatsCollector since implicit columns are not part of the parquet
footers. Can it be done elsewhere ? If it is absolutely needed here, you
should add a comment.
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