/*
 * 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;

/**
 * A mix in interface for {@link Scan}. Data sources can implement this interface to
 * report statistics to Spark.
 *
 * As of Spark 2.4, statistics are reported to the optimizer before any operator is pushed to the
 * data source. Implementations that return more accurate statistics based on pushed operators will
 * not improve query performance until the planner can push operators before getting stats.
 *
 * @since 3.0.0
 */
@Evolving
public interface SupportsReportStatistics extends Scan {

  /**
   * Returns the estimated statistics of this data source scan.
   */
  Statistics estimateStatistics();
}

/*
 * 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;

/**
 * A mix in interface for {@link Scan}. Data sources can implement this interface to
 * report statistics to Spark.
 *
 * As of Spark 3.0, statistics are reported to the optimizer after operators are pushed to the
 * data source. Implementations may return more accurate statistics based on pushed operators
 * which may improve query performance by providing better information to the optimizer.
 *
 * @since 3.0.0
 */
@Evolving
public interface SupportsReportStatistics extends Scan {

  /**
   * Returns the estimated statistics of this data source scan.
   */
  Statistics estimateStatistics();
}

Update documentation to reflect usage of updated statistics