public interface Statistics
This interface is used in the column SYS.SYSSTATISTICS.STATISTICS. It encapsulates information collected by the UPDATE STATISTICS command and is used internally by the Derby optimizer to estimate cost and selectivity of different query plans.
Modifier and Type | Method and Description |
---|---|
long |
getRowEstimate()
Returns the estimated number of rows in the index.
|
double |
selectivity(java.lang.Object[] predicates) |
Apache Derby V10.13 Internals - Copyright © 2004,2016 The Apache Software Foundation. All Rights Reserved.