cloud-fan commented on a change in pull request #30341: URL: https://github.com/apache/spark/pull/30341#discussion_r522818057
########## File path: sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/EvaluationRuntime.scala ########## @@ -0,0 +1,88 @@ +/* + * 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.spark.sql.catalyst.expressions + +import com.google.common.cache.{CacheBuilder, CacheLoader, LoadingCache} + +import org.apache.spark.sql.catalyst.InternalRow +import org.apache.spark.sql.internal.SQLConf + +/** + * This class helps subexpression elimination for interpreted evaluation + * in `InterpretedUnsafeProjection`. It maintains an evaluation cache. + * This class wraps `ExpressionProxy` around given expressions. The `ExpressionProxy` + * intercepts expression evaluation and loads from the cache first. + */ +class EvaluationRuntime { + + val cache: LoadingCache[ExpressionProxy, ResultProxy] = CacheBuilder.newBuilder() + .maximumSize(SQLConf.get.subexpressionEliminationCacheMaxEntries) + .build( + new CacheLoader[ExpressionProxy, ResultProxy]() { + override def load(expr: ExpressionProxy): ResultProxy = { + ResultProxy(expr.proxyEval(currentInput)) + } + }) + + private var currentInput: InternalRow = null + + /** + * Sets given input row as current row for evaluating expressions. This cleans up the cache + * too as new input comes. + */ + def setInput(input: InternalRow = null): Unit = { + currentInput = input + cache.invalidateAll() + } + + /** + * Finds subexpressions and wraps them with `ExpressionProxy`. + */ + def proxyExpressions(expressions: Seq[Expression]): Seq[Expression] = { + val equivalentExpressions: EquivalentExpressions = new EquivalentExpressions + + expressions.foreach(equivalentExpressions.addExprTree(_)) + + var proxyMap = Map.empty[Expression, ExpressionProxy] Review comment: shall we use a mutable map here? ---------------------------------------------------------------- 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. For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For additional commands, e-mail: reviews-h...@spark.apache.org
