shardulm94 commented on a change in pull request #933: URL: https://github.com/apache/iceberg/pull/933#discussion_r439606167
########## File path: mr/src/main/java/org/apache/iceberg/mr/mapred/IcebergFilterFactory.java ########## @@ -0,0 +1,158 @@ +/* + * 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.List; +import org.apache.hadoop.hive.ql.io.sarg.ExpressionTree; +import org.apache.hadoop.hive.ql.io.sarg.PredicateLeaf; +import org.apache.hadoop.hive.ql.io.sarg.SearchArgument; +import org.apache.iceberg.expressions.Expression; +import org.apache.iceberg.expressions.Expressions; + +import static org.apache.iceberg.expressions.Expressions.and; +import static org.apache.iceberg.expressions.Expressions.equal; +import static org.apache.iceberg.expressions.Expressions.greaterThanOrEqual; +import static org.apache.iceberg.expressions.Expressions.in; +import static org.apache.iceberg.expressions.Expressions.isNull; +import static org.apache.iceberg.expressions.Expressions.lessThan; +import static org.apache.iceberg.expressions.Expressions.lessThanOrEqual; +import static org.apache.iceberg.expressions.Expressions.not; +import static org.apache.iceberg.expressions.Expressions.notNull; +import static org.apache.iceberg.expressions.Expressions.or; + +public class IcebergFilterFactory { + + private IcebergFilterFactory() { + } + + public static Expression generateFilterExpression(SearchArgument sarg) { + List<PredicateLeaf> leaves = sarg.getLeaves(); + List<ExpressionTree> childNodes = sarg.getExpression().getChildren(); + + switch (sarg.getExpression().getOperator()) { + case OR: + ExpressionTree orLeft = childNodes.get(0); + ExpressionTree orRight = childNodes.get(1); + return or(translate(orLeft, leaves), translate(orRight, leaves)); + case AND: + ExpressionTree andLeft = childNodes.get(0); + ExpressionTree andRight = childNodes.get(1); + if (childNodes.size() > 2) { + Expression[] evaluatedChildren = getLeftoverLeaves(childNodes, leaves); + return and( + translate(andLeft, leaves), translate(andRight, leaves), evaluatedChildren); + } else { + return and(translate(andLeft, leaves), translate(andRight, leaves)); + } + case NOT: + return not(translateLeaf(sarg.getLeaves().get(0))); + case LEAF: + return translateLeaf(sarg.getLeaves().get(0)); + case CONSTANT: + return null; + default: + throw new IllegalStateException("Unknown operator: " + sarg.getExpression().getOperator()); + } + } + + /** + * Remove first 2 nodes already evaluated and return an array of the evaluated leftover nodes. + * @param allChildNodes All child nodes to be evaluated for the AND expression. + * @param leaves All instances of the leaf nodes. + * @return Array of leftover evaluated nodes. + */ + private static Expression[] getLeftoverLeaves(List<ExpressionTree> allChildNodes, List<PredicateLeaf> leaves) { + allChildNodes.remove(0); + allChildNodes.remove(0); + + Expression[] evaluatedLeaves = new Expression[allChildNodes.size()]; + for (int i = 0; i < allChildNodes.size(); i++) { + Expression filter = translate(allChildNodes.get(i), leaves); + evaluatedLeaves[i] = filter; + } + return evaluatedLeaves; + } + + /** + * Recursive method to traverse down the ExpressionTree to evaluate each expression and its leaf nodes. + * @param tree Current ExpressionTree where the 'top' node is being evaluated. + * @param leaves List of all leaf nodes within the tree. + * @return Expression that is translated from the Hive SearchArgument. + */ + private static Expression translate(ExpressionTree tree, List<PredicateLeaf> leaves) { + switch (tree.getOperator()) { + case OR: + return or(translate(tree.getChildren().get(0), leaves), + translate(tree.getChildren().get(1), leaves)); + case AND: + if (tree.getChildren().size() > 2) { + Expression[] evaluatedChildren = getLeftoverLeaves(tree.getChildren(), leaves); + return and(translate(tree.getChildren().get(0), leaves), + translate(tree.getChildren().get(1), leaves), evaluatedChildren); + } else { + return and(translate(tree.getChildren().get(0), leaves), + translate(tree.getChildren().get(1), leaves)); + } + case NOT: + return not(translate(tree.getChildren().get(0), leaves)); + case LEAF: + return translateLeaf(leaves.get(tree.getLeaf())); + case CONSTANT: + //We are unsure of how the CONSTANT case works, so using the approach of: + //https://github.com/apache/hive/blob/master/ql/src/java/org/apache/hadoop/hive/ql/io/parquet/read/ + // ParquetFilterPredicateConverter.java#L116 + return null; + default: + throw new IllegalStateException("Unknown operator: " + tree.getOperator()); + } + } + + /** + * Translate leaf nodes from Hive operator to Iceberg operator. + * @param leaf Leaf node + * @return Expression fully translated from Hive PredicateLeaf + */ + private static Expression translateLeaf(PredicateLeaf leaf) { + String column = leaf.getColumnName(); + if (column.equals("snapshot__id")) { + return Expressions.alwaysTrue(); + } + switch (leaf.getOperator()) { + case EQUALS: + return equal(column, leaf.getLiteral()); Review comment: Yup! Heres what Hive will give you https://github.com/apache/hive/blob/cb213d88304034393d68cc31a95be24f5aac62b6/storage-api/src/java/org/apache/hadoop/hive/ql/io/sarg/PredicateLeaf.java#L49-L56 but Iceberg expects https://github.com/linkedin/iceberg/blob/6e5601bbea2c032f11d90114e2c3e64dc6c0e5c3/api/src/main/java/org/apache/iceberg/types/Type.java#L29-L45. So you will need add conversions for the parity. Would also suggest adding one more test case which covers all datatypes that Hive can give us. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. 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