zhangjun0x01 commented on a change in pull request #1893: URL: https://github.com/apache/iceberg/pull/1893#discussion_r546487254
########## File path: flink/src/main/java/org/apache/iceberg/flink/FlinkFilters.java ########## @@ -0,0 +1,183 @@ +/* + * 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.flink; + +import java.util.List; +import java.util.Map; +import java.util.Optional; +import java.util.function.BiFunction; +import java.util.stream.Collectors; +import org.apache.flink.table.expressions.CallExpression; +import org.apache.flink.table.expressions.FieldReferenceExpression; +import org.apache.flink.table.expressions.ResolvedExpression; +import org.apache.flink.table.expressions.ValueLiteralExpression; +import org.apache.flink.table.functions.BuiltInFunctionDefinition; +import org.apache.flink.table.functions.BuiltInFunctionDefinitions; +import org.apache.iceberg.expressions.Expression; +import org.apache.iceberg.expressions.Expression.Operation; +import org.apache.iceberg.expressions.Expressions; +import org.apache.iceberg.relocated.com.google.common.base.Preconditions; +import org.apache.iceberg.relocated.com.google.common.collect.ImmutableMap; +import org.apache.iceberg.util.NaNUtil; + +public class FlinkFilters { + private FlinkFilters() { + } + + private static final Map<BuiltInFunctionDefinition, Operation> FILTERS = ImmutableMap + .<BuiltInFunctionDefinition, Operation>builder() + .put(BuiltInFunctionDefinitions.EQUALS, Operation.EQ) + .put(BuiltInFunctionDefinitions.NOT_EQUALS, Operation.NOT_EQ) + .put(BuiltInFunctionDefinitions.GREATER_THAN, Operation.GT) + .put(BuiltInFunctionDefinitions.GREATER_THAN_OR_EQUAL, Operation.GT_EQ) + .put(BuiltInFunctionDefinitions.LESS_THAN, Operation.LT) + .put(BuiltInFunctionDefinitions.LESS_THAN_OR_EQUAL, Operation.LT_EQ) + .put(BuiltInFunctionDefinitions.IN, Operation.IN) + .put(BuiltInFunctionDefinitions.IS_NULL, Operation.IS_NULL) + .put(BuiltInFunctionDefinitions.IS_NOT_NULL, Operation.NOT_NULL) + .put(BuiltInFunctionDefinitions.AND, Operation.AND) + .put(BuiltInFunctionDefinitions.OR, Operation.OR) + .put(BuiltInFunctionDefinitions.NOT, Operation.NOT) + .build(); + + + public static Optional<Expression> convert(org.apache.flink.table.expressions.Expression flinkExpression) { + if (!(flinkExpression instanceof CallExpression)) { + return Optional.empty(); + } + + CallExpression call = (CallExpression) flinkExpression; + Operation op = FILTERS.get(call.getFunctionDefinition()); + if (op != null) { + switch (op) { + case IS_NULL: + FieldReferenceExpression isNullFilter = (FieldReferenceExpression) call.getResolvedChildren().get(0); + return Optional.of(Expressions.isNull(isNullFilter.getName())); + + case NOT_NULL: + FieldReferenceExpression notNullExpression = (FieldReferenceExpression) call.getResolvedChildren().get(0); + return Optional.of(Expressions.notNull(notNullExpression.getName())); + + case LT: + return convertComparisonExpression(Expressions::lessThan, call); + + case LT_EQ: + return convertComparisonExpression(Expressions::lessThanOrEqual, call); + + case GT: + return convertComparisonExpression(Expressions::greaterThan, call); + + case GT_EQ: + return convertComparisonExpression(Expressions::greaterThanOrEqual, call); + + case EQ: + return convertComparisonExpression(Expressions::equal, call); + + case NOT_EQ: + return convertComparisonExpression(Expressions::notEqual, call); + + case IN: + List<ResolvedExpression> args = call.getResolvedChildren(); + FieldReferenceExpression field = (FieldReferenceExpression) args.get(0); + List<ResolvedExpression> values = args.subList(1, args.size()); + + List<Object> inputValues = values.stream().filter( + expression -> { + if (expression instanceof ValueLiteralExpression) { + return !((ValueLiteralExpression) flinkExpression).isNull(); + } + + return false; + } + ).map(expression -> { + ValueLiteralExpression valueLiteralExpression = (ValueLiteralExpression) expression; + return valueLiteralExpression.getValueAs(valueLiteralExpression.getOutputDataType().getConversionClass()) + .get(); + }).collect(Collectors.toList()); + return Optional.of(Expressions.in(field.getName(), inputValues)); + + case NOT: + Optional<Expression> child = convert(call.getResolvedChildren().get(0)); + if (child.isPresent()) { + return Optional.of(Expressions.not(child.get())); + } + + return Optional.empty(); + + case AND: { + return convertLogicExpression(Expressions::and, call); + } + + case OR: { + return convertLogicExpression(Expressions::or, call); + } + } + } + + return Optional.empty(); + } + + private static Optional<Expression> convertLogicExpression(BiFunction<Expression, Expression, Expression> function, + CallExpression call) { + List<ResolvedExpression> args = call.getResolvedChildren(); + Optional<Expression> left = convert(args.get(0)); + Optional<Expression> right = convert(args.get(1)); + if (left.isPresent() && right.isPresent()) { + return Optional.of(function.apply(left.get(), right.get())); + } + + return Optional.empty(); + } + + private static Optional<Expression> convertComparisonExpression(BiFunction<String, Object, Expression> function, + CallExpression call) { + List<ResolvedExpression> args = call.getResolvedChildren(); + FieldReferenceExpression fieldReferenceExpression; + ValueLiteralExpression valueLiteralExpression; + if (literalOnRight(args)) { + fieldReferenceExpression = (FieldReferenceExpression) args.get(0); + valueLiteralExpression = (ValueLiteralExpression) args.get(1); + } else { + fieldReferenceExpression = (FieldReferenceExpression) args.get(1); + valueLiteralExpression = (ValueLiteralExpression) args.get(0); + } + + String name = fieldReferenceExpression.getName(); + Class clazz = valueLiteralExpression.getOutputDataType().getConversionClass(); + Object value = valueLiteralExpression.getValueAs(clazz).get(); Review comment: I tested it ,if the sql is `select * from mytable where data = null` ,it do not supports filter push down in flink,and we do not can get any data. if the sql is `select * from mytable where data is null`, it is normal ,and It will enter the `IS_NULL` branch of switch ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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