| org.apache.derby.iapi.sql.compile.Optimizable
All known Subclasses: org.apache.derby.impl.sql.compile.FromTable,
| Optimizable | | public interface Optimizable (Code) | | Optimizable provides services for optimizing a table in a query.
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| Method Summary | |
| boolean | considerSortAvoidancePath()
Check whether this optimizable's sort avoidance path should
be considered. | | public int | convertAbsoluteToRelativeColumnPosition(int absolutePosition)
Convert an absolute to a relative 0-based column position.
This is useful when generating qualifiers for partial rows
from the store.
Parameters:
absolutePosition - The absolute 0-based column position for the column. | | CostEstimate | estimateCost(OptimizablePredicateList predList, ConglomerateDescriptor cd, CostEstimate outerCost, Optimizer optimizer, RowOrdering rowOrdering)
Estimate the cost of scanning this Optimizable using the given
predicate list with the given conglomerate. | | public boolean | feasibleJoinStrategy(OptimizablePredicateList predList, Optimizer optimizer)
| | public boolean | forUpdate()
| | public String | getBaseTableName()
Get the table name of this Optimizable. | | AccessPath | getBestAccessPath()
Get the best access path for this Optimizable. | | AccessPath | getBestSortAvoidancePath()
Get the best sort-avoidance path for this Optimizable. | | AccessPath | getCurrentAccessPath()
| | public DataDictionary | getDataDictionary()
Get the DataDictionary from this Optimizable. | | public String | getName()
| | public int | getNumColumnsReturned()
Get the number of the number of columns returned by this Optimizable. | | public Properties | getProperties()
Get the Properties list, if any, associated with this optimizable. | | JBitSet | getReferencedTableMap()
Get the map of referenced tables for this Optimizable. | | int | getResultSetNumber()
| | TableDescriptor | getTableDescriptor()
Get the table descriptor for this table (if any). | | int | getTableNumber()
| | AccessPath | getTrulyTheBestAccessPath()
Get the best access path overall for this Optimizable. | | boolean | hasTableNumber()
| | public int[] | hashKeyColumns()
| | public void | initAccessPaths(Optimizer optimizer)
Init the access paths for this optimizable. | | public int | initialCapacity()
| | boolean | isBaseTable()
| | public boolean | isCoveringIndex(ConglomerateDescriptor cd)
Return whether or not this is a covering index. | | boolean | isMaterializable()
| | public boolean | isOneRowScan()
| | public boolean | isTargetTable()
| | public boolean | legalJoinOrder(JBitSet assignedTableMap)
Can this Optimizable appear at the current location in the join order. | | public float | loadFactor()
| | public int | maxCapacity(JoinStrategy joinStrategy, int maxMemoryPerTable)
Return the maximum capacity of the hash table, for hash join strategy
Parameters:
maxMemoryPerTable - The maximum number of bytes to be used. | | public boolean | memoryUsageOK(double rowCount, int maxMemoryPerTable)
| | Optimizable | modifyAccessPath(JBitSet outerTables)
Modify the access path for this Optimizable, as necessary. | | boolean | nextAccessPath(Optimizer optimizer, OptimizablePredicateList predList, RowOrdering rowOrdering)
Choose the next access path to evaluate for this Optimizable.
Parameters:
optimizer - Optimizer to use.
Parameters:
predList - The predicate list for this optimizable.The optimizer always passes null, and it is upto the optimizable object to pass along itsown predicate list, if appropriate, when delegatingthis method.
Parameters:
rowOrdering - The row ordering for all the outer tables inthe join order. | | CostEstimate | optimizeIt(Optimizer optimizer, OptimizablePredicateList predList, CostEstimate outerCost, RowOrdering rowOrdering)
Choose the best access path for this Optimizable.
Parameters:
optimizer - Optimizer to use.
Parameters:
predList - The predicate list to optimize against
Parameters:
outerCost - The CostEstimate for the outer tables in the join order,telling how many times this Optimizable will be scanned.
Parameters:
rowOrdering - The row ordering for all the tables in thejoin order, including this one. | | void | pullOptPredicates(OptimizablePredicateList optimizablePredicates)
Pull all the OptimizablePredicates from this Optimizable and put them
in the given OptimizablePredicateList. | | boolean | pushOptPredicate(OptimizablePredicate optimizablePredicate)
Push an OptimizablePredicate down, if this node accepts it.
Parameters:
optimizablePredicate - OptimizablePredicate to push down. | | public void | rememberAsBest(int planType, Optimizer optimizer)
Remember the current access path as the best one (so far). | | void | rememberJoinStrategyAsBest(AccessPath ap)
Remember the current join strategy as the best one so far in this
join order. | | void | rememberSortAvoidancePath()
Mark this optimizable so that its sort avoidance path will be
considered. | | public void | setHashKeyColumns(int[] columnNumbers)
| | public void | setProperties(Properties tableProperties)
Set the Properties list for this optimizalbe. | | public void | startOptimizing(Optimizer optimizer, RowOrdering rowOrdering)
Begin the optimization process for this Optimizable. | | boolean | supportsMultipleInstantiations()
| | public double | uniqueJoin(OptimizablePredicateList predList)
Does this optimizable have a uniqueness condition on the
given predicate list, and if so, how many unique keys will be
returned per scan. | | public void | updateBestPlanMap(short action, Object planKey)
When remembering "truly the best" access path for an Optimizable, we
have to keep track of which OptimizerImpl the "truly the best" access
is for. | | public void | verifyProperties(DataDictionary dDictionary)
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| considerSortAvoidancePath | | boolean considerSortAvoidancePath()(Code) | | Check whether this optimizable's sort avoidance path should
be considered.
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| convertAbsoluteToRelativeColumnPosition | | public int convertAbsoluteToRelativeColumnPosition(int absolutePosition)(Code) | | Convert an absolute to a relative 0-based column position.
This is useful when generating qualifiers for partial rows
from the store.
Parameters:
absolutePosition - The absolute 0-based column position for the column. The relative 0-based column position for the column. |
| estimateCost | | CostEstimate estimateCost(OptimizablePredicateList predList, ConglomerateDescriptor cd, CostEstimate outerCost, Optimizer optimizer, RowOrdering rowOrdering) throws StandardException(Code) | | Estimate the cost of scanning this Optimizable using the given
predicate list with the given conglomerate. It is assumed that the
predicate list has already been classified. This cost estimate is
just for one scan, not for the life of the query.
See Also: OptimizablePredicateList.classify
Parameters:
predList - The predicate list to optimize against
Parameters:
cd - The conglomerate descriptor to get the cost of
Parameters:
outerCost - The estimated cost of the part of the plan outerto this optimizable.
Parameters:
optimizer - The optimizer to use to help estimate the cost
Parameters:
rowOrdering - The row ordering for all the tables in thejoin order, including this one. The estimated cost of doing the scan
exception:
StandardException - Thrown on error |
| feasibleJoinStrategy | | public boolean feasibleJoinStrategy(OptimizablePredicateList predList, Optimizer optimizer) throws StandardException(Code) | | Is the current proposed join strategy for this optimizable feasible
given the predicate list?
Parameters:
predList - The predicate list that has been pushed down tothis optimizable
Parameters:
optimizer - The optimizer to use. true means feasible
exception:
StandardException - Thrown on error |
| forUpdate | | public boolean forUpdate()(Code) | | Return true if this is the target table of an update
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| getBaseTableName | | public String getBaseTableName()(Code) | | Get the table name of this Optimizable. Only base tables have
table names (by the time we use this method, all views will have
been resolved).
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| getBestAccessPath | | AccessPath getBestAccessPath()(Code) | | Get the best access path for this Optimizable.
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| getBestSortAvoidancePath | | AccessPath getBestSortAvoidancePath()(Code) | | Get the best sort-avoidance path for this Optimizable.
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| getCurrentAccessPath | | AccessPath getCurrentAccessPath()(Code) | | Get the current access path under consideration for this Optimizable
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| getDataDictionary | | public DataDictionary getDataDictionary() throws StandardException(Code) | | Get the DataDictionary from this Optimizable. This is useful for code generation
because we need to get the constraint name if scanning a back index so that
RunTimeStatistics can display the correct info.
The DataDictionary to use.
exception:
StandardException - Thrown on error |
| getNumColumnsReturned | | public int getNumColumnsReturned()(Code) | | Get the number of the number of columns returned by this Optimizable.
The number of the number of columns returned by this Optimizable. |
| getProperties | | public Properties getProperties()(Code) | | Get the Properties list, if any, associated with this optimizable.
The Properties list, if any, associated with this optimizable. |
| getReferencedTableMap | | JBitSet getReferencedTableMap()(Code) | | Get the map of referenced tables for this Optimizable.
JBitSet Referenced table map. |
| getResultSetNumber | | int getResultSetNumber()(Code) | | Get this Optimizable's result set number
|
| getTableDescriptor | | TableDescriptor getTableDescriptor()(Code) | | Get the table descriptor for this table (if any). Only base tables
have table descriptors - for the rest of the optimizables, this
method returns null.
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| getTableNumber | | int getTableNumber()(Code) | | Get this Optimizable's table number
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| getTrulyTheBestAccessPath | | AccessPath getTrulyTheBestAccessPath()(Code) | | Get the best access path overall for this Optimizable.
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| hasTableNumber | | boolean hasTableNumber()(Code) | | Return true if this Optimizable has a table number
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| hashKeyColumns | | public int[] hashKeyColumns()(Code) | | Return the hash key column numbers, for hash join strategy
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| initAccessPaths | | public void initAccessPaths(Optimizer optimizer)(Code) | | Init the access paths for this optimizable.
Parameters:
optimizer - The optimizer being used. |
| initialCapacity | | public int initialCapacity()(Code) | | Return the initial capacity of the hash table, for hash join strategy
|
| isBaseTable | | boolean isBaseTable()(Code) | | Tell whether this Optimizable represents a base table
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| isCoveringIndex | | public boolean isCoveringIndex(ConglomerateDescriptor cd) throws StandardException(Code) | | Return whether or not this is a covering index. We expect to call this
during generation, after access path selection is complete.
Parameters:
cd - ConglomerateDesriptor for index to consider boolean Whether or not this is a covering index.
exception:
StandardException - Thrown on error |
| isOneRowScan | | public boolean isOneRowScan() throws StandardException(Code) | | Will the optimizable return at most 1 row per scan?
Whether or not the optimizable will return at most 1 row per scan?
exception:
StandardException - Thrown on error |
| isTargetTable | | public boolean isTargetTable()(Code) | | Is the optimizable the target table of an update or delete?
Whether or not the optimizable the target table of an update or delete. |
| legalJoinOrder | | public boolean legalJoinOrder(JBitSet assignedTableMap)(Code) | | Can this Optimizable appear at the current location in the join order.
In other words, have the Optimizable's dependencies been satisfied?
Parameters:
assignedTableMap - The tables that have been placed so far in the join order. Where or not this Optimizable can appear at the current location in the join order. |
| loadFactor | | public float loadFactor()(Code) | | Return the load factor of the hash table, for hash join strategy
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| maxCapacity | | public int maxCapacity(JoinStrategy joinStrategy, int maxMemoryPerTable) throws StandardException(Code) | | Return the maximum capacity of the hash table, for hash join strategy
Parameters:
maxMemoryPerTable - The maximum number of bytes to be used. Ignored if the user has set a maximumnumber of rows for the Optimizable.
exception:
StandardException - Standard error policy |
| memoryUsageOK | | public boolean memoryUsageOK(double rowCount, int maxMemoryPerTable) throws StandardException(Code) | |
Parameters:
rowCount -
Parameters:
maxMemoryPerTable - true if the memory usage of the proposed access path is OK, false if not.
exception:
StandardException - standard error policy |
| modifyAccessPath | | Optimizable modifyAccessPath(JBitSet outerTables) throws StandardException(Code) | | Modify the access path for this Optimizable, as necessary. This includes
things like adding a result set to translate from index rows to base rows
Parameters:
outerTables - Bit map of the tables that are outer to this onein the join order. The (potentially new) Optimizable at the top of the tree.
exception:
StandardException - Thrown on error |
| nextAccessPath | | boolean nextAccessPath(Optimizer optimizer, OptimizablePredicateList predList, RowOrdering rowOrdering) throws StandardException(Code) | | Choose the next access path to evaluate for this Optimizable.
Parameters:
optimizer - Optimizer to use.
Parameters:
predList - The predicate list for this optimizable.The optimizer always passes null, and it is upto the optimizable object to pass along itsown predicate list, if appropriate, when delegatingthis method.
Parameters:
rowOrdering - The row ordering for all the outer tables inthe join order. This method will add the orderingof the next access path to the given RowOrdering. true means another access path was chosen, false meansno more access paths to evaluate.
exception:
StandardException - Thrown on error |
| optimizeIt | | CostEstimate optimizeIt(Optimizer optimizer, OptimizablePredicateList predList, CostEstimate outerCost, RowOrdering rowOrdering) throws StandardException(Code) | | Choose the best access path for this Optimizable.
Parameters:
optimizer - Optimizer to use.
Parameters:
predList - The predicate list to optimize against
Parameters:
outerCost - The CostEstimate for the outer tables in the join order,telling how many times this Optimizable will be scanned.
Parameters:
rowOrdering - The row ordering for all the tables in thejoin order, including this one. The optimizer's estimated cost of the best access path.
exception:
StandardException - Thrown on error |
| pullOptPredicates | | void pullOptPredicates(OptimizablePredicateList optimizablePredicates) throws StandardException(Code) | | Pull all the OptimizablePredicates from this Optimizable and put them
in the given OptimizablePredicateList.
Parameters:
optimizablePredicates - The list to put the pulled predicatesin.
exception:
StandardException - Thrown on error |
| pushOptPredicate | | boolean pushOptPredicate(OptimizablePredicate optimizablePredicate) throws StandardException(Code) | | Push an OptimizablePredicate down, if this node accepts it.
Parameters:
optimizablePredicate - OptimizablePredicate to push down. Whether or not the predicate was pushed down.
exception:
StandardException - Thrown on error |
| rememberAsBest | | public void rememberAsBest(int planType, Optimizer optimizer) throws StandardException(Code) | | Remember the current access path as the best one (so far).
Parameters:
planType - The type of plan (one of Optimizer.NORMAL_PLANor Optimizer.SORT_AVOIDANCE_PLAN)
Parameters:
optimizer - The OptimizerImpl that is telling this Optimizableto remember its current path as "truly the best".
exception:
StandardException - thrown on error. |
| rememberJoinStrategyAsBest | | void rememberJoinStrategyAsBest(AccessPath ap)(Code) | | Remember the current join strategy as the best one so far in this
join order.
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| rememberSortAvoidancePath | | void rememberSortAvoidancePath()(Code) | | Mark this optimizable so that its sort avoidance path will be
considered.
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| setHashKeyColumns | | public void setHashKeyColumns(int[] columnNumbers)(Code) | | Set the hash key column numbers, for hash join strategy
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| setProperties | | public void setProperties(Properties tableProperties)(Code) | | Set the Properties list for this optimizalbe.
Parameters:
tableProperties - The Properties list for this optimizable. |
| startOptimizing | | public void startOptimizing(Optimizer optimizer, RowOrdering rowOrdering)(Code) | | Begin the optimization process for this Optimizable. This can be
called many times for an Optimizable while optimizing a query -
it will typically be called every time the Optimizable is placed
in a potential join order.
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| supportsMultipleInstantiations | | boolean supportsMultipleInstantiations()(Code) | | Tell whether this Optimizable can be instantiated multiple times
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| uniqueJoin | | public double uniqueJoin(OptimizablePredicateList predList) throws StandardException(Code) | | Does this optimizable have a uniqueness condition on the
given predicate list, and if so, how many unique keys will be
returned per scan.
Parameters:
predList - The predicate list to check <= 0 means there is no uniqueness condition> 0 means there is a uniqueness condition,and the return value is the number of rows per scan.
exception:
StandardException - Thrown on error |
| updateBestPlanMap | | public void updateBestPlanMap(short action, Object planKey) throws StandardException(Code) | | When remembering "truly the best" access path for an Optimizable, we
have to keep track of which OptimizerImpl the "truly the best" access
is for. In most queries there will only be one OptimizerImpl in
question, but in cases where there are nested subqueries, there will be
one OptimizerImpl for every level of nesting, and each OptimizerImpl
might have its own idea of what this Optimizable's "truly the best path"
access path really is. In addition, there could be Optimizables
above this Optimizable that might need to override the best path
chosen during optimization. So whenever we save a "truly the best" path,
we take note of which Optimizer/Optimizable told us to do so. Then
as each level of subquery finishes optimization, the corresponding
OptimizerImpl/Optimizable can load its preferred access path into this
Optimizable's trulyTheBestAccessPath field and pass it up the tree, until
eventually the outer-most OptimizerImpl can choose to either use the best
path that it received from below (by calling "rememberAsBest()") or else
use the path that it found to be "best" for itself.
This method is what allows us to keep track of which OptimizerImpl or
Optimizable saved which "best plan", and allows us to load the
appropriate plans after each round of optimization.
Parameters:
action - Indicates whether we're adding, loading, or removinga best plan for the OptimizerImpl/Optimizable.
Parameters:
planKey - Object to use as the map key when adding/looking upa plan. If it is an instance of OptimizerImpl then it correspondsto an outer query; otherwise it's some Optimizable above thisOptimizable that could potentially reject plans chosen by theOptimizerImpl to which this Optimizable belongs. |
| verifyProperties | | public void verifyProperties(DataDictionary dDictionary) throws StandardException(Code) | | Verify that the Properties list with optimizer overrides, if specified, is valid
Parameters:
dDictionary - The DataDictionary to use.
exception:
StandardException - Thrown on error |
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