Uses of Class
edu.caltech.nanodb.queryeval.ColumnStats

Packages that use ColumnStats

Package	Description
edu.caltech.nanodb.functions	This package contains the abstractions for supporting simple functions, aggregate functions, and table-returning functions in NanoDB.
edu.caltech.nanodb.plannodes	This package contains classes for representing query execution plans, as well as analyzing their costs.
edu.caltech.nanodb.queryeval	This package contains the query-evaluation components of the database.

Uses of ColumnStats in edu.caltech.nanodb.functions

Methods in edu.caltech.nanodb.functions that return types with arguments of type ColumnStats

Modifier and Type	Method	Description
abstract java.util.ArrayList<ColumnStats>	TableFunction.getStats()	Returns statistics (possibly estimated) describing the results that this plan node will produce.

Uses of ColumnStats in edu.caltech.nanodb.plannodes

Fields in edu.caltech.nanodb.plannodes with type parameters of type ColumnStats

Modifier and Type	Field	Description
protected java.util.ArrayList<ColumnStats>	ThetaJoinNode.leftStats	The cached statistics of the left subplan, used for cost estimation.
protected java.util.ArrayList<ColumnStats>	ThetaJoinNode.rightStats	The cached statistics of the right subplan, used for cost estimation.
protected java.util.ArrayList<ColumnStats>	PlanNode.stats	Statistics (possibly estimated) describing the results produced by this plan node.

Methods in edu.caltech.nanodb.plannodes that return types with arguments of type ColumnStats

Modifier and Type	Method	Description
java.util.ArrayList<ColumnStats>	PlanNode.getStats()	Returns statistics (possibly estimated) describing the results that this plan node will produce.

Method parameters in edu.caltech.nanodb.plannodes with type arguments of type ColumnStats

Modifier and Type	Method	Description
protected void	ProjectNode.prepareSchemaStats(Schema inputSchema, java.util.ArrayList<ColumnStats> inputStats)	This helper function computes the schema of the project plan-node, based on the schema of its child-plan, and also the expressions specified in the project operation.

Uses of ColumnStats in edu.caltech.nanodb.queryeval

Fields in edu.caltech.nanodb.queryeval with type parameters of type ColumnStats

Modifier and Type	Field	Description
private java.util.ArrayList<ColumnStats>	TableStats.columnStats	This collection holds statistics about individual columns in the table.

Methods in edu.caltech.nanodb.queryeval that return ColumnStats

Modifier and Type	Method	Description
ColumnStats	ColumnStatsCollector.getColumnStats()	This helper method constructs and returns a new column-statistics object containing the stats collected by this object.
ColumnStats	TableStats.getColumnStats(int index)	Returns the column-statistics for the specified column.

Methods in edu.caltech.nanodb.queryeval that return types with arguments of type ColumnStats

Modifier and Type	Method	Description
java.util.ArrayList<ColumnStats>	TableStats.getAllColumnStats()	Returns the collection of all column-statistics collected for this table.
static java.util.ArrayList<ColumnStats>	StatisticsUpdater.updateStats(Expression expr, Schema schema, java.util.List<ColumnStats> inputStats)	This static helper takes a selection predicate, a schema the predicate is evaluated against, and input column-statistics, and produces output column-statistics that reflect the input arguments.

Method parameters in edu.caltech.nanodb.queryeval with type arguments of type ColumnStats

Modifier and Type	Method	Description
static float	SelectivityEstimator.estimateBoolOperSelectivity(BooleanOperator bool, Schema exprSchema, java.util.ArrayList<ColumnStats> stats)	This function computes a selectivity estimate for a general Boolean expression that may be comprised of one or more components.
private static float	SelectivityEstimator.estimateCompareColumnColumn(CompareOperator.Type compType, ColumnValue columnOne, ColumnValue columnTwo, Schema exprSchema, java.util.ArrayList<ColumnStats> stats)	This helper function computes a selectivity estimate for a comparison between two columns.
private static float	SelectivityEstimator.estimateCompareColumnValue(CompareOperator.Type compType, ColumnValue columnValue, LiteralValue literalValue, Schema exprSchema, java.util.ArrayList<ColumnStats> stats)	This helper function computes a selectivity estimate for a comparison between a column and a literal value.
static float	SelectivityEstimator.estimateCompareSelectivity(CompareOperator comp, Schema exprSchema, java.util.ArrayList<ColumnStats> stats)	This function computes a selectivity estimate for a general comparison operation.
static float	SelectivityEstimator.estimateSelectivity(Expression expr, Schema exprSchema, java.util.ArrayList<ColumnStats> stats)	This function computes the selectivity of a selection predicate, using table statistics and other estimates to make an educated guess.
private static void	StatisticsUpdater.updateCompareStats(CompareOperator comp, Schema schema, java.util.List<ColumnStats> stats)	Try to update the column-statistics based on the passed-in comparison operation.
static java.util.ArrayList<ColumnStats>	StatisticsUpdater.updateStats(Expression expr, Schema schema, java.util.List<ColumnStats> inputStats)	This static helper takes a selection predicate, a schema the predicate is evaluated against, and input column-statistics, and produces output column-statistics that reflect the input arguments.

Constructors in edu.caltech.nanodb.queryeval with parameters of type ColumnStats

Constructor	Description
ColumnStats(ColumnStats stats)	Copies another column-stats object into this object.

Constructor parameters in edu.caltech.nanodb.queryeval with type arguments of type ColumnStats

Constructor	Description
TableStats(int numDataPages, int numTuples, float avgTupleSize, java.util.ArrayList<ColumnStats> columnStats)	Create a new table-statistics object with the stats set to the specified values.