spark SupportsPushDownTopN 源码
spark SupportsPushDownTopN 代码
文件路径：/sql/catalyst/src/main/java/org/apache/spark/sql/connector/read/SupportsPushDownTopN.java
/*
* 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.connector.read;
import org.apache.spark.annotation.Evolving;
import org.apache.spark.sql.connector.expressions.SortOrder;
/**
* A mix-in interface for {@link ScanBuilder}. Data sources can implement this interface to
* push down top N(query with ORDER BY ... LIMIT n). We can push down top N with many other
* operations if they follow the operator order we defined in {@link ScanBuilder}'s class doc.
*
* @since 3.3.0
*/
@Evolving
public interface SupportsPushDownTopN extends ScanBuilder {
/**
* Pushes down top N to the data source.
*/
boolean pushTopN(SortOrder[] orders, int limit);
/**
* Whether the top N is partially pushed or not. If it returns true, then Spark will do top N
* again. This method will only be called when {@link #pushTopN} returns true.
*/
default boolean isPartiallyPushed() { return true; }
}
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