/**
* 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.hadoop.hive.ql.metadata;
import org.apache.hadoop.hive.ql.exec.TableScanOperator;
import org.apache.hadoop.mapred.JobConf;
// Plugin interface for storage handler which supports input estimation
public interface InputEstimator {
/**
* Estimate input size based on filter and projection on table scan operator
*
* @param remaining Early exit condition. If it has positive value, further estimation
* can be canceled on the point of exceeding it. In this case,
* return any bigger length value then this (Long.MAX_VALUE, for eaxmple).
*/
Estimation estimate(JobConf job, TableScanOperator ts, long remaining) throws HiveException;
public static class Estimation {
private int rowCount;
private long totalLength;
public Estimation(int rowCount, long totalLength) {
this.rowCount = rowCount;
this.totalLength = totalLength;
}
public int getRowCount() {
return rowCount;
}
public long getTotalLength() {
return totalLength;
}
}
}