[GitHub] [iceberg] jackye1995 commented on a change in pull request #2609: Adds SortRewriteStrategy

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jackye1995 commented on a change in pull request #2609:
URL: https://github.com/apache/iceberg/pull/2609#discussion_r669820275



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File path: core/src/main/java/org/apache/iceberg/actions/SortStrategy.java
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@@ -0,0 +1,124 @@
+/*
+ * 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.iceberg.actions;
+
+import java.util.Map;
+import java.util.Set;
+import org.apache.iceberg.FileScanTask;
+import org.apache.iceberg.SortOrder;
+import org.apache.iceberg.relocated.com.google.common.base.Preconditions;
+import org.apache.iceberg.relocated.com.google.common.collect.ImmutableSet;
+import org.apache.iceberg.util.PropertyUtil;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * A rewrite strategy for data files which aims to reorder data with data files to optimally lay them out
+ * in relation to a column. For example, if the Sort strategy is used on a set of files which is ordered
+ * by column x and original has files File A (x: 0 - 50), File B ( x: 10 - 40) and File C ( x: 30 - 60),
+ * this Strategy will attempt to rewrite those files into File A' (x: 0-20), File B' (x: 21 - 40),
+ * File C' (x: 41 - 60).
+ * <p>
+ * Currently the there is no clustering detection and we will rewrite all files if {@link SortStrategy#REWRITE_ALL}

Review comment:
       Have we thought about how we will support clustering in the future? Is it going to be:
   1. another strategy that extends this `SortStrategy`
   2. additional configurations in this strategy
   3. or something else?
   
   I am just wondering this approach for extending `BinPackStrategy` is extensible in the long run as different strategies might have inter-dependencies with each other. If this is just one config or maybe plus a few additional configs for clustering in the future, would it be better to just directly make them configurations in the `BinPackStrategy`?




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