org.apache.hadoop.hive.ql.metadata.InputEstimator Maven / Gradle / Ivy
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*
* http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.hadoop.hive.ql.metadata;
import org.apache.hadoop.hive.common.classification.InterfaceAudience;
import org.apache.hadoop.hive.common.classification.InterfaceStability;
import org.apache.hadoop.hive.ql.exec.TableScanOperator;
import org.apache.hadoop.mapred.JobConf;
// Plugin interface for storage handler which supports input estimation
@InterfaceAudience.Public
@InterfaceStability.Stable
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;
}
}
}