Constructor Detail

• HashJoinStrategy

  HashJoinStrategy()

Method Detail

• feasible

  public boolean feasible​(Optimizable innerTable,
                          OptimizablePredicateList predList,
                          Optimizer optimizer)
                   throws StandardException

  Description copied from interface: JoinStrategy
  Is this join strategy feasible under the circumstances?

  Parameters:

  innerTable - The inner table of the join

  predList - The predicateList for the join

  optimizer - The optimizer to use

  Returns:

  true means the strategy is feasible, false means it isn't

  Throws:

  StandardException - Thrown on error

  See Also:

  JoinStrategy.feasible(org.apache.derby.iapi.sql.compile.Optimizable, org.apache.derby.iapi.sql.compile.OptimizablePredicateList, org.apache.derby.iapi.sql.compile.Optimizer)

• ignoreBulkFetch

  public boolean ignoreBulkFetch()

  Description copied from interface: JoinStrategy
  Should we just ignore bulk fetch with this join strategy?

  Specified by:

  ignoreBulkFetch in interface JoinStrategy

  Overrides:

  ignoreBulkFetch in class BaseJoinStrategy

  See Also:

  JoinStrategy.ignoreBulkFetch()

• multiplyBaseCostByOuterRows

  public boolean multiplyBaseCostByOuterRows()

  Description copied from interface: JoinStrategy
  Returns true if the base cost of scanning the conglomerate should be multiplied by the number of outer rows.

  See Also:

  JoinStrategy.multiplyBaseCostByOuterRows()

• getBasePredicates

  public OptimizablePredicateList getBasePredicates​(OptimizablePredicateList predList,
                                                    OptimizablePredicateList basePredicates,
                                                    Optimizable innerTable)
                                             throws StandardException

  Description copied from interface: JoinStrategy
  Get the base predicates for this join strategy. The base predicates are the ones that can be used while scanning the table. For some join strategies (for example, nested loop), all predicates are base predicates. For other join strategies (for example, hash join), the base predicates are those that involve comparisons with constant expressions. Also, order the base predicates according to the order in the proposed conglomerate descriptor for the inner table.

  Parameters:

  predList - The predicate list to pull from.

  basePredicates - The list to put the base predicates in.

  innerTable - The inner table of the join

  Returns:

  The base predicate list. If no predicates are pulled, it may return the source predList without doing anything.

  Throws:

  StandardException - Thrown on error

  See Also:

  JoinStrategy.getBasePredicates(org.apache.derby.iapi.sql.compile.OptimizablePredicateList, org.apache.derby.iapi.sql.compile.OptimizablePredicateList, org.apache.derby.iapi.sql.compile.Optimizable)

• nonBasePredicateSelectivity

  public double nonBasePredicateSelectivity​(Optimizable innerTable,
                                            OptimizablePredicateList predList)
                                     throws StandardException

  Description copied from interface: JoinStrategy
  Get the extra selectivity of the non-base predicates (those that were left in the predicate list by getBasePredicates() that are not applied to the scan of the base conglomerate. NOTE: For some types of join strategy, it may not remove any predicates from the original predicate list. The join strategy is expected to know when it does this, and to return 1.0 as the extra selectivity in these cases.

  Parameters:

  innerTable - The inner table of the join.

  predList - The original predicate list that was passed to getBasePredicates(), from which some base predicates may have been pulled.

  Returns:

  The extra selectivity due to non-base predicates

  Throws:

  StandardException

  See Also:

  JoinStrategy.nonBasePredicateSelectivity(org.apache.derby.iapi.sql.compile.Optimizable, org.apache.derby.iapi.sql.compile.OptimizablePredicateList)

• putBasePredicates

  public void putBasePredicates​(OptimizablePredicateList predList,
                                OptimizablePredicateList basePredicates)
                         throws StandardException

  Description copied from interface: JoinStrategy
  Put back and base predicates that were removed from the list by getBasePredicates (see above). NOTE: Those join strategies that treat all predicates as base predicates may treat the get and put methods as no-ops.

  Parameters:

  predList - The list of predicates to put the base predicates back in.

  basePredicates - The base predicates to put back in the list.

  Throws:

  StandardException - Thrown on error

  See Also:

  JoinStrategy.putBasePredicates(org.apache.derby.iapi.sql.compile.OptimizablePredicateList, org.apache.derby.iapi.sql.compile.OptimizablePredicateList)

• estimateCost

  public void estimateCost​(Optimizable innerTable,
                           OptimizablePredicateList predList,
                           ConglomerateDescriptor cd,
                           CostEstimate outerCost,
                           Optimizer optimizer,
                           CostEstimate costEstimate)

  Description copied from interface: JoinStrategy
  Get the estimated cost for the join.

  Parameters:

  innerTable - The inner table to join with

  predList - The predicate list for the join

  cd - The conglomerate descriptor (if appropriate) to get the cost of

  outerCost - The estimated cost of the part of the plan outer to the inner table

  optimizer - The optimizer to use to help estimate the cost

  costEstimate - The estimated cost of doing a single scan of the inner table, to be filled in with the cost of doing the join.

  See Also:

  JoinStrategy.estimateCost(org.apache.derby.iapi.sql.compile.Optimizable, org.apache.derby.iapi.sql.compile.OptimizablePredicateList, org.apache.derby.iapi.sql.dictionary.ConglomerateDescriptor, org.apache.derby.iapi.sql.compile.CostEstimate, org.apache.derby.iapi.sql.compile.Optimizer, org.apache.derby.iapi.sql.compile.CostEstimate)

• maxCapacity

  public int maxCapacity​(int userSpecifiedCapacity,
                         int maxMemoryPerTable,
                         double perRowUsage)

  maxMemoryPerTable - maximum number of bytes per table

  perRowUsage - number of bytes per row

  Returns:

  The maximum number of rows that can be handled by this join strategy

  See Also:

  JoinStrategy.maxCapacity(int, int, double)

• getName

  public java.lang.String getName()

  Description copied from interface: JoinStrategy
  Get the name of this join strategy

  See Also:

  JoinStrategy.getName()

• scanCostType

  public int scanCostType()

  Description copied from interface: JoinStrategy
  Get the costing type, for use with StoreCostController.getScanCost

  See Also:

  JoinStrategy.scanCostType()

• getOperatorSymbol

  public java.lang.String getOperatorSymbol()

  Description copied from interface: JoinStrategy
  Get the operator symbol used to represent this join strategy in optimizer traces

  See Also:

  JoinStrategy.getOperatorSymbol()

• resultSetMethodName

  public java.lang.String resultSetMethodName​(boolean bulkFetch,
                                              boolean multiprobe,
                                              boolean validatingCheckConstraint)

  Description copied from interface: JoinStrategy
  Get the name of the result set method for base table scans

  Parameters:

  bulkFetch - True means bulk fetch is being done on the inner table

  multiprobe - True means we are probing the inner table for rows matching a specified list of values.

  validatingCheckConstraint - True of this is a special scan to validate a check constraint.

  See Also:

  JoinStrategy.resultSetMethodName(boolean, boolean, boolean)

• joinResultSetMethodName

  public java.lang.String joinResultSetMethodName()

  Description copied from interface: JoinStrategy
  Get the name of the join result set method for the join

  See Also:

  JoinStrategy.joinResultSetMethodName()

• halfOuterJoinResultSetMethodName

  public java.lang.String halfOuterJoinResultSetMethodName()

  Description copied from interface: JoinStrategy
  Get the name of the join result set method for the half outerjoin

  See Also:

  JoinStrategy.halfOuterJoinResultSetMethodName()

• getScanArgs

  public int getScanArgs​(TransactionController tc,
                         MethodBuilder mb,
                         Optimizable innerTable,
                         OptimizablePredicateList storeRestrictionList,
                         OptimizablePredicateList nonStoreRestrictionList,
                         ExpressionClassBuilderInterface acbi,
                         int bulkFetch,
                         int resultRowTemplate,
                         int colRefItem,
                         int indexColItem,
                         int lockMode,
                         boolean tableLocked,
                         int isolationLevel,
                         int maxMemoryPerTable,
                         boolean genInListVals)
                  throws StandardException

  Description copied from interface: JoinStrategy
  Get the appropriate arguments to the scan for this type of join.

  Parameters:

  tc - The TransactionController

  mb - The method to generate the arguments in

  innerTable - The inner table of the join

  storeRestrictionList - The predicate list to be evaluated in the store

  nonStoreRestrictionList - The predicate list to be evaluated outside of the store

  acbi - The expression class builder for the activation class we're building

  bulkFetch - The amount of bulk fetch to do

  resultRowTemplate - The saved object index of a result row template

  colRefItem - The item number of the column reference bit map

  lockMode - The lock mode to use when scanning the table (see TransactionController).

  tableLocked - Whether or not the table is marked (in sys.systables) as always using table locking

  isolationLevel - Isolation level specified (or not) for scans

  maxMemoryPerTable - Max memory per table

  genInListVals - Whether or not we are going to generate IN-list values with which to probe the inner table.

  Returns:

  Count of the expressions pushed to use as the parameters to the result set for the inner table

  Throws:

  StandardException - Thrown on error

  See Also:

  JoinStrategy.getScanArgs(org.apache.derby.iapi.store.access.TransactionController, org.apache.derby.iapi.services.compiler.MethodBuilder, org.apache.derby.iapi.sql.compile.Optimizable, org.apache.derby.iapi.sql.compile.OptimizablePredicateList, org.apache.derby.iapi.sql.compile.OptimizablePredicateList, org.apache.derby.iapi.sql.compile.ExpressionClassBuilderInterface, int, int, int, int, int, boolean, int, int, boolean)

• divideUpPredicateLists

  public void divideUpPredicateLists​(Optimizable innerTable,
                                     OptimizablePredicateList originalRestrictionList,
                                     OptimizablePredicateList storeRestrictionList,
                                     OptimizablePredicateList nonStoreRestrictionList,
                                     OptimizablePredicateList requalificationRestrictionList,
                                     DataDictionary dd)
                              throws StandardException

  Description copied from interface: JoinStrategy
  Divide up the predicates into different lists for different phases of the operation. When this method is called, all of the predicates will be in restrictionList. The effect of this method is to remove all of the predicates from restrictionList except those that will be pushed down to the store as start/stop predicates or Qualifiers. The remaining predicates will be put into nonBaseTableRestrictionList. All predicate lists will be ordered as necessary for use with the conglomerate. Some operations (like hash join) materialize results, and so require requalification of rows when doing a non-covering index scan. The predicates to use for requalification are copied into baseTableRestrictionList.

  Parameters:

  innerTable - The inner table of the join

  originalRestrictionList - Initially contains all predicates. This method removes predicates from this list and moves them to other lists, as appropriate.

  storeRestrictionList - To be filled in with predicates to be pushed down to store.

  nonStoreRestrictionList - To be filled in with predicates that are not pushed down to the store.

  requalificationRestrictionList - Copy of predicates used to re-qualify rows, if necessary.

  dd - The DataDictionary

  Throws:

  StandardException - Thrown on error

  See Also:

  JoinStrategy.divideUpPredicateLists(org.apache.derby.iapi.sql.compile.Optimizable, org.apache.derby.iapi.sql.compile.OptimizablePredicateList, org.apache.derby.iapi.sql.compile.OptimizablePredicateList, org.apache.derby.iapi.sql.compile.OptimizablePredicateList, org.apache.derby.iapi.sql.compile.OptimizablePredicateList, org.apache.derby.iapi.sql.dictionary.DataDictionary)

• isHashJoin

  public boolean isHashJoin()

  Description copied from interface: JoinStrategy
  Is this a form of hash join?

  Specified by:

  isHashJoin in interface JoinStrategy

  Overrides:

  isHashJoin in class BaseJoinStrategy

  Returns:

  Whether or not this strategy is a form of hash join.

  See Also:

  JoinStrategy.isHashJoin()

• doesMaterialization

  public boolean doesMaterialization()

  Description copied from interface: JoinStrategy
  Is materialization built in to the join strategy?

  Returns:

  Whether or not materialization is built in to the join strategy

  See Also:

  JoinStrategy.doesMaterialization()

• findHashKeyColumns

  private int[] findHashKeyColumns​(Optimizable innerTable,
                                   ConglomerateDescriptor cd,
                                   OptimizablePredicateList predList)
                            throws StandardException

  Find the hash key columns, if any, to use with this join.

  Parameters:

  innerTable - The inner table of the join

  cd - The conglomerate descriptor to use on inner table

  predList - The predicate list to look for the equijoin in

  Returns:

  the numbers of the hash key columns, or null if no hash key column

  Throws:

  StandardException - Thrown on error

• toString

  public java.lang.String toString()

  Overrides:

  toString in class java.lang.Object