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https://issues.apache.org/jira/browse/PARQUET-2366?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17777612#comment-17777612
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ASF GitHub Bot commented on PARQUET-2366:
-----------------------------------------
ConeyLiu commented on code in PR #1174:
URL: https://github.com/apache/parquet-mr/pull/1174#discussion_r1366603099
##########
parquet-hadoop/src/main/java/org/apache/parquet/hadoop/PrefetchIndexCache.java:
##########
@@ -0,0 +1,156 @@
+/*
+ * 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.parquet.hadoop;
+
+import org.apache.parquet.Preconditions;
+import org.apache.parquet.column.values.bloomfilter.BloomFilter;
+import org.apache.parquet.hadoop.metadata.BlockMetaData;
+import org.apache.parquet.hadoop.metadata.ColumnChunkMetaData;
+import org.apache.parquet.hadoop.metadata.ColumnPath;
+import org.apache.parquet.internal.column.columnindex.ColumnIndex;
+import org.apache.parquet.internal.column.columnindex.OffsetIndex;
+
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * This index cache will prefetch those columns' indexes when calling {@link
#setBlockMetadata(BlockMetaData)}.
+ * <p>
+ *
+ * Note: the given index will be freed from the cache after calling the
related get method.
+ */
+class PrefetchIndexCache implements IndexCache {
+ private final ParquetFileReader fileReader;
+ private final Set<ColumnPath> columns;
+
+ private Map<ColumnPath, ColumnIndex> columnIndexCache;
+ private Map<ColumnPath, OffsetIndex> offsetIndexCache;
+ private Map<ColumnPath, BloomFilter> bloomIndexCache;
+
+ PrefetchIndexCache(
+ ParquetFileReader fileReader,
+ Set<ColumnPath> columns) {
+ this.fileReader = fileReader;
+ this.columns = columns;
+ }
+
+ @Override
+ public void setBlockMetadata(BlockMetaData currentBlockMetadata) throws
IOException {
+ this.columnIndexCache = readAllColumnIndexes(currentBlockMetadata);
+ this.offsetIndexCache = readAllOffsetIndexes(currentBlockMetadata);
+ this.bloomIndexCache = readAllBloomFilters(currentBlockMetadata);
+ }
+
+ @Override
+ public ColumnIndex getColumnIndex(ColumnChunkMetaData chunk) throws
IOException {
+ ColumnPath columnPath = chunk.getPath();
+ if (columns.contains(columnPath)) {
+ Preconditions.checkState(
+ columnIndexCache.containsKey(columnPath),
+ "Not found cached ColumnIndex for column: %s with cache strategy: %s",
+ columnPath.toDotString(),
+ CacheStrategy.PRECACHE_BLOCK);
+ }
+
+ return columnIndexCache.remove(columnPath);
Review Comment:
I added the parameter: `freeCacheAfterGet` to enable it or not.
> Optimize random seek during rewriting
> -------------------------------------
>
> Key: PARQUET-2366
> URL: https://issues.apache.org/jira/browse/PARQUET-2366
> Project: Parquet
> Issue Type: Improvement
> Reporter: Xianyang Liu
> Priority: Major
>
> The `ColunIndex`, `OffsetIndex`, and `BloomFilter` are stored at the end of
> the file. We need to randomly seek 4 times when rewriting a column chunk. We
> found this could impact the rewrite performance heavily for files with a
> number of columns(~1000). In this PR, we read the `ColumnIndex`,
> `OffsetIndex`, and `BloomFilter` into a cache to avoid the random seek. We
> got about 60 times performance improvement in production environments for the
> files with about one thousand columns.
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