Interface OptimizableList
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- All Known Implementing Classes:
FromList
public interface OptimizableList
OptimizableList provides services for optimizing a list of Optimizables (tables) in a query.
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description Optimizable
getOptimizable(int n)
Return the nth Optimizable in the list.void
initAccessPaths(Optimizer optimizer)
Init the access paths for these optimizables.boolean
legalJoinOrder(int numTablesInQuery)
Tell whether the join order is legal.boolean
optimizeJoinOrder()
Tell whether the join order should be optimized.void
reOrder(int[] joinOrder)
Set the join order for this list of optimizables.void
setOptimizable(int n, Optimizable optimizable)
Set the nth Optimizable to the specified Optimizable.int
size()
Return the number of Optimizables in the list.boolean
useStatistics()
user can specify that s/he doesn't want statistics to be considered when optimizing the query.void
verifyProperties(DataDictionary dDictionary)
Verify that the Properties list with optimizer overrides, if specified, is valid
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Method Detail
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size
int size()
Return the number of Optimizables in the list.- Returns:
- integer The number of Optimizables in the list.
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getOptimizable
Optimizable getOptimizable(int n)
Return the nth Optimizable in the list.- Parameters:
n
- "index" (0 based) into the list.- Returns:
- Optimizable The nth Optimizables in the list.
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setOptimizable
void setOptimizable(int n, Optimizable optimizable)
Set the nth Optimizable to the specified Optimizable.- Parameters:
n
- "index" (0 based) into the list.optimizable
- New nth Optimizable.
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verifyProperties
void verifyProperties(DataDictionary dDictionary) throws StandardException
Verify that the Properties list with optimizer overrides, if specified, is valid- Parameters:
dDictionary
- The DataDictionary to use.- Throws:
StandardException
- Thrown on error
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reOrder
void reOrder(int[] joinOrder)
Set the join order for this list of optimizables. The join order is represented as an array of integers - each entry in the array stands for the order of the corresponding element in the list. For example, a joinOrder of {2, 0, 1} means that the 3rd Optimizable in the list (element 2, since we are zero-based) is the first one in the join order, followed by the 1st element in the list, and finally by the 2nd element in the list. This method shuffles this OptimizableList to match the join order. Obviously, the size of the array must equal the number of elements in the array, and the values in the array must be between 0 and the number of elements in the array minus 1, and the values in the array must be unique.
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useStatistics
boolean useStatistics()
user can specify that s/he doesn't want statistics to be considered when optimizing the query.
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optimizeJoinOrder
boolean optimizeJoinOrder()
Tell whether the join order should be optimized.
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legalJoinOrder
boolean legalJoinOrder(int numTablesInQuery)
Tell whether the join order is legal.
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initAccessPaths
void initAccessPaths(Optimizer optimizer)
Init the access paths for these optimizables.- Parameters:
optimizer
- The optimizer being used.
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