clintropolis commented on code in PR #14654: URL: https://github.com/apache/druid/pull/14654#discussion_r1276899020
########## processing/src/main/java/org/apache/druid/query/filter/FallbackPredicate.java: ########## @@ -0,0 +1,66 @@ +/* + * 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.druid.query.filter; + +import com.google.common.base.Predicate; +import org.apache.druid.math.expr.ExprEval; +import org.apache.druid.math.expr.ExpressionType; + +import javax.annotation.Nullable; + +/** + * {@link Predicate} that wraps another predicate and can catch {@link ClassCastException} from some + * {@link java.util.Comparator} and degrades into casting input to an expected {@link ExpressionType} once an exception + * is encountered. Useful when processing data that might be mixed types, despite what the column capabilities might + * claim the type is, such as variant 'auto' types. This class is not thread-safe. + */ +public class FallbackPredicate<T> implements Predicate<T> +{ + private final Predicate<T> delegate; + private final ExpressionType expectedType; + private boolean needsCast = false; + + public FallbackPredicate(Predicate<T> delegate, ExpressionType expectedType) + { + this.delegate = delegate; + this.expectedType = expectedType; + } + + @Override + public boolean apply(@Nullable T input) + { + if (needsCast) { + return castApply(input); + } + try { + return delegate.apply(input); + } + catch (ClassCastException caster) { Review Comment: i believe it should happen at most once per predicate creation - so once per segment when used with a value matcher for filtered offset or predicate based index for a bitmap offset, and once per filtered aggregate when used with filtered aggs. I agree they are expensive, that is why i did it like this to catch the exception on the first value that has a problem that throws it and then set the `needsCast` flag to always take the casting path for all checks after that, which is also expensive but I think should be less so than throwing exceptions every row. -- 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] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
