gaborgsomogyi commented on code in PR #28142: URL: https://github.com/apache/flink/pull/28142#discussion_r3334448992
########## flink-libraries/flink-state-processing-api/src/main/java/org/apache/flink/state/api/filter/BoundComparison.java: ########## @@ -0,0 +1,62 @@ +/* + * 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.flink.state.api.filter; + +import javax.annotation.Nullable; + +import java.io.Serializable; + +/** Comparison strategy resolved from the bound types at filter construction time. */ +enum BoundComparison implements Serializable { + LONG { + @Override + public int compare(Object a, Object b) { + return Long.compare(((Number) a).longValue(), ((Number) b).longValue()); + } + }, + DOUBLE { + @Override + public int compare(Object a, Object b) { + return Double.compare(((Number) a).doubleValue(), ((Number) b).doubleValue()); + } + }, + NATURAL { + @SuppressWarnings("unchecked") + @Override + public int compare(Object a, Object b) { + return ((Comparable<Object>) a).compareTo(b); + } + }; + + public abstract int compare(Object a, Object b); + + static BoundComparison resolve(@Nullable Object lower, @Nullable Object upper) { + if (isFloatingPoint(lower) || isFloatingPoint(upper)) { + return DOUBLE; + } + if (lower instanceof Number || upper instanceof Number) { + return LONG; + } + return NATURAL; + } Review Comment: Could you elaborate on why `BoundComparison` is needed at all? `SavepointFilters.extractValue()` calls `literal.getValueAs(cls)` where `cls` is derived from the column's own `DataType.getConversionClass()`. This means the bound is already normalised to the exact Java type of the column (a `BIGINT` column produces a `Long` bound, an `INT` column produces an `Integer` bound). Since the key in state is also typed to the column declaration, bound and key are always the same Java type. `Comparable.compareTo` is therefore always type-safe, and the widening in `LONG`/`DOUBLE` appears to solve a problem that `getValueAs` already prevents upstream. Beyond the motivation question there is a correctness issue: `BigDecimal` (Flink `DECIMAL`) is a `Number`, so `resolve()` routes it to `LONG` and calls `.longValue()`, silently truncating the value. A range filter on a `DECIMAL` key column will compare incorrectly. Finally, any function where supporting a new type requires adding a new branch is a design smell. The logic should either be derivable from the type system or pushed to the type itself. If `BoundComparison` cannot be removed entirely, the comparator should be derived from the Flink `DataType` at filter construction time in `SavepointFilters` (where `DataType` is available), so `RangeKeyFilter` holds an opaque `Comparator<Object>` and this class disappears. -- 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. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
