[GitHub] [iceberg] rdblue commented on a change in pull request #1107: Add IcebergStorageHandler

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

rdblue commented on a change in pull request #1107:
URL: https://github.com/apache/iceberg/pull/1107#discussion_r458951872



##########
File path: mr/src/main/java/org/apache/iceberg/mr/mapred/IcebergStorageHandler.java
##########
@@ -0,0 +1,115 @@
+/*
+ * 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.mr.mapred;
+
+import java.util.Map;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.hive.metastore.HiveMetaHook;
+import org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat;
+import org.apache.hadoop.hive.ql.metadata.HiveException;
+import org.apache.hadoop.hive.ql.metadata.HiveStorageHandler;
+import org.apache.hadoop.hive.ql.metadata.HiveStoragePredicateHandler;
+import org.apache.hadoop.hive.ql.plan.ExprNodeDesc;
+import org.apache.hadoop.hive.ql.plan.ExprNodeGenericFuncDesc;
+import org.apache.hadoop.hive.ql.plan.TableDesc;
+import org.apache.hadoop.hive.ql.security.authorization.HiveAuthorizationProvider;
+import org.apache.hadoop.hive.serde2.AbstractSerDe;
+import org.apache.hadoop.hive.serde2.Deserializer;
+import org.apache.hadoop.mapred.InputFormat;
+import org.apache.hadoop.mapred.JobConf;
+import org.apache.hadoop.mapred.OutputFormat;
+
+public class IcebergStorageHandler implements HiveStoragePredicateHandler, HiveStorageHandler {
+
+  private Configuration conf;
+
+  @Override
+  public Class<? extends InputFormat> getInputFormatClass() {
+    return IcebergInputFormat.class;
+  }
+
+  @Override
+  public Class<? extends OutputFormat> getOutputFormatClass() {
+    return HiveIgnoreKeyTextOutputFormat.class;
+  }
+
+  @Override
+  public Class<? extends AbstractSerDe> getSerDeClass() {
+    return IcebergSerDe.class;
+  }
+
+  @Override
+  public HiveMetaHook getMetaHook() {
+    return null;
+  }
+
+  @Override
+  public HiveAuthorizationProvider getAuthorizationProvider() throws HiveException {
+    return null;
+  }
+
+  @Override
+  public void configureInputJobProperties(TableDesc tableDesc, Map<String, String> map) {
+
+  }
+
+  @Override
+  public void configureOutputJobProperties(TableDesc tableDesc, Map<String, String> map) {
+
+  }
+
+  @Override
+  public void configureTableJobProperties(TableDesc tableDesc, Map<String, String> map) {
+
+  }
+
+  @Override
+  public void configureJobConf(TableDesc tableDesc, JobConf jobConf) {
+
+  }
+
+  @Override
+  public Configuration getConf() {
+    return conf;
+  }
+
+  @Override
+  public void setConf(Configuration conf) {
+    this.conf = conf;
+  }
+  @Override
+  public String toString() {
+    return this.getClass().getName();
+  }
+
+  /**
+   * @param jobConf Job configuration for InputFormat to access
+   * @param deserializer Deserializer
+   * @param exprNodeDesc Filter expression extracted by Hive
+   * @return Entire filter to take advantage of Hive's pruning as well as Iceberg's pruning.
+   */
+  @Override
+  public DecomposedPredicate decomposePredicate(JobConf jobConf, Deserializer deserializer, ExprNodeDesc exprNodeDesc) {
+    DecomposedPredicate predicate = new DecomposedPredicate();
+    predicate.residualPredicate = (ExprNodeGenericFuncDesc) exprNodeDesc;

Review comment:
       The challenge here is that Iceberg produces per-split residuals, so we would need to return them for each split, or find the common filter that needs to be applied to all splits.
   
   There's also a question of whether Hive or Iceberg is better at doing the filtering. For vectorized reads, Iceberg may be better. But for row-based reads, engines are typically better. That's why we delegate final filtering to Spark, which will benefit from that engine's codegen.




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