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A CostEstimate represents the cost of getting a ResultSet, along with the ordering of rows in the ResultSet, and the estimated number of rows in this ResultSet.
Method Summary | |
CostEstimate |
add(CostEstimate addend,
CostEstimate retval)
Add this cost estimate to another one. |
CostEstimate |
cloneMe()
Get a copy of this CostEstimate |
double |
compare(CostEstimate other)
Compare this cost estimate with the given cost estimate. |
CostEstimate |
divide(double divisor,
CostEstimate retval)
Divide this cost estimate by a scalar, non-dimensional number. |
boolean |
isUninitialized()
Return whether or not this CostEstimate is uninitialized. |
CostEstimate |
multiply(double multiplicand,
CostEstimate retval)
Multiply this cost estimate by a scalar, non-dimensional number. |
double |
rowCount()
Get the estimated number of rows returned by the ResultSet that this CostEstimate models. |
void |
setCost(CostEstimate other)
Copy the values from the given cost estimate into this one. |
void |
setCost(double cost,
double rowCount,
double singleScanRowCount)
Set the cost for this cost estimate. |
void |
setSingleScanRowCount(double singleRowScanCount)
Set the single scan row count. |
double |
singleScanRowCount()
Get the estimated number of rows returned by a single scan of the ResultSet that this CostEstimate models. |
Methods inherited from interface org.apache.derby.iapi.store.access.StoreCostResult |
getEstimatedCost, getEstimatedRowCount, setEstimatedCost, setEstimatedRowCount |
Method Detail |
public void setCost(double cost, double rowCount, double singleScanRowCount)
public void setCost(CostEstimate other)
public void setSingleScanRowCount(double singleRowScanCount)
public double compare(CostEstimate other)
other
- The cost estimate to compare this one with
public CostEstimate add(CostEstimate addend, CostEstimate retval)
addend
- This cost estimate to add this one to.retval
- If non-null, put the result here.
public CostEstimate multiply(double multiplicand, CostEstimate retval)
multiplicand
- The value to multiply this CostEstimate by.retval
- If non-null, put the result here.
public CostEstimate divide(double divisor, CostEstimate retval)
divisor
- The value to divide this CostEstimate by.retval
- If non-null, put the result here.
public double rowCount()
public double singleScanRowCount()
public CostEstimate cloneMe()
public boolean isUninitialized()
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