ibis::jRange Class Reference

In-memory Range Join. More...

#include <jrange.h>

Inheritance diagram for ibis::jRange:

Public Member Functions
virtual int64_t	count () const
	Compute the number of results. More...
template<typename T >
ibis::table *	fillResult (size_t nrows, double delta1, double delta2, const std::string &desc, const ibis::array_t< T > &rjcol, const ibis::table::typeArray &rtypes, const ibis::table::bufferArray &rbuff, const ibis::array_t< T > &sjcol, const ibis::table::typeArray &stypes, const ibis::table::bufferArray &sbuff, const ibis::table::stringArray &tcname, const std::vector< uint32_t > &tcnpos)
	Generate a table representing a range-join in memory. More...
	jRange (const ibis::part &partr, const ibis::part &parts, const ibis::column &colr, const ibis::column &cols, double delta1, double delta2, const ibis::qExpr *condr, const ibis::qExpr *conds, const ibis::selectClause *sel, const ibis::fromClause *frm, const char *desc)
	Constructor.
virtual void	roughCount (uint64_t &nmin, uint64_t &nmax) const
	Estimate the number of hits. Nothing useful at this time.
virtual ibis::table *	select () const
	Produce a projection of the joint table. More...
virtual ibis::table *	select (const char *) const
	Produce a project based on the given select clause. More...
virtual ibis::table *	select (const ibis::table::stringArray &colnames) const
	Produce a projection of all known data partitions. More...
virtual	~jRange ()
	Destructor.

Static Protected Member Functions
template<typename T >
static table *	fillResult (size_t nrows, double delta1, double delta2, const std::string &desc, const ibis::array_t< T > &rjcol, const ibis::table::typeArray &rtypes, const ibis::table::bufferArray &rbuff, const ibis::array_t< T > &sjcol, const ibis::table::typeArray &stypes, const ibis::table::bufferArray &sbuff, const ibis::table::stringArray &cnamet, const std::vector< uint32_t > &cnpos)

Protected Attributes
const ibis::column &	colr_
const ibis::column &	cols_
const double	delta1_
const double	delta2_
std::string	desc_
const ibis::fromClause *	frm_
ibis::bitvector	maskr_
ibis::bitvector	masks_
int64_t	nrows
array_t< uint32_t > *	orderr_
array_t< uint32_t > *	orders_
const ibis::part &	partr_
const ibis::part &	parts_
const ibis::selectClause *	sel_
void *	valr_
void *	vals_

Additional Inherited Members
Static Public Member Functions inherited from ibis::quaere
static quaere *	create (const char *sel, const char *from, const char *where)
	Create a query object using the global datasets.
static quaere *	create (const char *sel, const char *from, const char *where, const ibis::partList &prts)
	Generate a query expression. More...
static quaere *	create (const ibis::part *partr, const ibis::part *parts, const char *colname, const char *condr=0, const char *conds=0, const char *sel=0)
	Specify a natural join operation. More...
Protected Member Functions inherited from ibis::quaere
	quaere ()
	Default constructor. Only used by derived classes.

Detailed Description

In-memory Range Join.

A range join is a SQL query of the form

SELECT count(*) FROM partR, partS WHERE
  delta1 <= partR.colR - partS.colS <= delta2
  and conditions-on-partR and conditions-on-partS;

or

SELECT count(*) FROM partR, partS WHERE partR.colR between
  partS.colS + delta1 and partS.colS + delta2 and
  conditions-on-partR and conditions-on-partS;

where delta1 and delta2 are constants.

Warning

This is an experimental feature of FastBit. The current design is very limited and is likely to go through major revisions frequently. Feel free to express your opinions on the FastBit mailing list fastb.nosp@m.it-u.nosp@m.sers@.nosp@m.hpcr.nosp@m.dm.lb.nosp@m.l.go.nosp@m.v.

Member Function Documentation

int64_t ibis::jRange::count ( ) const

virtual

Compute the number of results.

This function provides the exact answer. If it fails to do so, it will return a negative number to indicate error.

Implements ibis::quaere.

References ibis::DOUBLE, ibis::FLOAT, ibis::INT, ibis::LONG, ibis::SHORT, ibis::util::sortMerge(), ibis::UBYTE, ibis::UINT, ibis::ULONG, and ibis::USHORT.

template<typename T >

ibis::table* ibis::jRange::fillResult	(	size_t	nrows,
		double	delta1,
		double	delta2,
		const std::string &	desc,
		const ibis::array_t< T > &	rjcol,
		const ibis::table::typeArray &	rtypes,
		const ibis::table::bufferArray &	rbuff,
		const ibis::array_t< T > &	sjcol,
		const ibis::table::typeArray &	stypes,
		const ibis::table::bufferArray &	sbuff,
		const ibis::table::stringArray &	tcname,
		const std::vector< uint32_t > &	tcnpos
	)

Generate a table representing a range-join in memory.

The input to this function are values to go into the resulting table; it only needs to match the rows and fill the output table.

Note

This implementation is for elementary numberical data types only.

References ibis::table::allocateBuffer(), ibis::bord::copyValue(), ibis::table::freeBuffers(), ibis::util::ref(), ibis::util::shortName(), ibis::array_t< T >::size(), and ibis::UNKNOWN_TYPE.

ibis::table * ibis::jRange::select ( ) const

virtual

Produce a projection of the joint table.

The select clause associated with the query object is evaluated. If no select clause is provided, it returns a table with no columns. This is different from having a 'count(*)' as the select clause, which produce a table with one row and one column.

Note

We assume that this query object might be reused later and therefore store partial results associated with the query object.

Implements ibis::quaere.

References ibis::table::describe(), ibis::table::nColumns(), ibis::table::nRows(), ibis::array_t< T >::push_back(), ibis::math::barrel::recordVariable(), ibis::array_t< T >::reserve(), and ibis::util::shortName().

ibis::table * ibis::jRange::select ( const char *  ) const

virtual

Produce a project based on the given select clause.

The joint data table is defined by the where clause and the from clause given to the constructor of this object.

Implements ibis::quaere.

References ibis::selectClause::aggExpr(), ibis::selectClause::aggSize(), ibis::table::describe(), ibis::selectClause::getAggregator(), ibis::table::nColumns(), ibis::table::nRows(), ibis::array_t< T >::push_back(), ibis::math::barrel::recordVariable(), ibis::array_t< T >::reserve(), and ibis::util::shortName().

ibis::table * ibis::jRange::select ( const ibis::table::stringArray &  colnames ) const

virtual

Produce a projection of all known data partitions.

This function selects all values of the named columns that are not NULL.

Note

This function assumes that this query object is used only once and therefore does not cache the results.

fill the in-memory buffer

Implements ibis::quaere.

References ibis::CATEGORY, ibis::DOUBLE, ibis::FLOAT, ibis::table::freeBuffers(), ibis::category::getDictionary(), ibis::bord::column::getDictionary(), ibis::INT, ibis::LONG, ibis::util::ref(), ibis::util::reorder(), ibis::bord::column::setDictionary(), ibis::SHORT, ibis::util::shortName(), ibis::array_t< T >::size(), ibis::TEXT, ibis::column::type(), ibis::TYPESTRING, ibis::UBYTE, ibis::UINT, ibis::ULONG, ibis::UNKNOWN_TYPE, and ibis::USHORT.

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The documentation for this class was generated from the following files:

• jrange.h
• jrange.cpp