Namespaces | Classes | Typedefs | Enumerations | Functions | Variables
Xapian Namespace Reference

The Xapian namespace contains public interfaces for the Xapian library. More...

Namespaces

 Auto
 Database factory functions which determine the database type automatically.
 
 Chert
 Database factory functions for the chert backend.
 
 InMemory
 Database factory functions for the inmemory backend.
 
 Remote
 Database factory functions for the remote backend.
 
 Unicode
 Functions associated with handling Unicode characters.
 

Classes

class  AssertionError
 AssertionError is thrown if a logical assertion inside Xapian fails. More...
 
class  BB2Weight
 This class implements the BB2 weighting scheme. More...
 
class  BM25PlusWeight
 Xapian::Weight subclass implementing the BM25+ probabilistic formula. More...
 
class  BM25Weight
 Xapian::Weight subclass implementing the BM25 probabilistic formula. More...
 
class  BoolWeight
 Class implementing a "boolean" weighting scheme. More...
 
class  Compactor
 Compact a database, or merge and compact several. More...
 
class  CoordWeight
 Xapian::Weight subclass implementing Coordinate Matching. More...
 
class  Database
 This class is used to access a database, or a group of databases. More...
 
class  DatabaseCorruptError
 DatabaseCorruptError indicates database corruption was detected. More...
 
class  DatabaseCreateError
 DatabaseCreateError indicates a failure to create a database. More...
 
class  DatabaseError
 DatabaseError indicates some sort of database related error. More...
 
class  DatabaseLockError
 DatabaseLockError indicates failure to lock a database. More...
 
class  DatabaseModifiedError
 DatabaseModifiedError indicates a database was modified. More...
 
class  DatabaseOpeningError
 DatabaseOpeningError indicates failure to open a database. More...
 
class  DatabaseVersionError
 DatabaseVersionError indicates that a database is in an unsupported format. More...
 
class  DateRangeProcessor
 Handle a date range. More...
 
class  DateValueRangeProcessor
 Handle a date range. More...
 
class  DecreasingValueWeightPostingSource
 Read weights from a value which is known to decrease as docid increases. More...
 
class  DLHWeight
 This class implements the DLH weighting scheme, which is a representative scheme of the Divergence from Randomness Framework by Gianni Amati. More...
 
class  DocNotFoundError
 Indicates an attempt to access a document not present in the database. More...
 
class  Document
 A handle representing a document in a Xapian database. More...
 
class  DPHWeight
 This class implements the DPH weighting scheme. More...
 
class  Enquire
 This class provides an interface to the information retrieval system for the purpose of searching. More...
 
class  Error
 All exceptions thrown by Xapian are subclasses of Xapian::Error. More...
 
class  ErrorHandler
 Decide if a Xapian::Error exception should be ignored. More...
 
class  ESet
 Class representing a list of search results. More...
 
class  ESetIterator
 Iterator over a Xapian::ESet. More...
 
class  ExpandDecider
 Virtual base class for expand decider functor. More...
 
class  ExpandDeciderAnd
 ExpandDecider subclass which rejects terms using two ExpandDeciders. More...
 
class  ExpandDeciderFilterPrefix
 ExpandDecider subclass which restrict terms to a particular prefix. More...
 
class  ExpandDeciderFilterTerms
 ExpandDecider subclass which rejects terms in a specified list. More...
 
class  FeatureUnavailableError
 Indicates an attempt to use a feature which is unavailable. More...
 
class  FieldProcessor
 Base class for field processors. More...
 
class  FixedWeightPostingSource
 A posting source which returns a fixed weight for all documents. More...
 
class  GreatCircleMetric
 Calculate the great-circle distance between two coordinates on a sphere. More...
 
class  IfB2Weight
 This class implements the IfB2 weighting scheme. More...
 
class  IneB2Weight
 This class implements the IneB2 weighting scheme. More...
 
class  InL2Weight
 This class implements the InL2 weighting scheme. More...
 
class  InternalError
 InternalError indicates a runtime problem of some sort. More...
 
class  InvalidArgumentError
 InvalidArgumentError indicates an invalid parameter value was passed to the API. More...
 
class  InvalidOperationError
 InvalidOperationError indicates the API was used in an invalid way. More...
 
class  KeyMaker
 Virtual base class for key making functors. More...
 
struct  LatLongCoord
 A latitude-longitude coordinate. More...
 
class  LatLongCoords
 A sequence of latitude-longitude coordinates. More...
 
class  LatLongCoordsIterator
 An iterator across the values in a LatLongCoords object. More...
 
class  LatLongDistanceKeyMaker
 KeyMaker subclass which sorts by distance from a latitude/longitude. More...
 
class  LatLongDistancePostingSource
 Posting source which returns a weight based on geospatial distance. More...
 
class  LatLongMetric
 Base class for calculating distances between two lat/long coordinates. More...
 
class  LMWeight
 Xapian::Weight subclass implementing the Language Model formula. More...
 
class  LogicError
 The base class for exceptions indicating errors in the program logic. More...
 
class  MatchDecider
 Base class for matcher decision functor. More...
 
class  MatchSpy
 Abstract base class for match spies. More...
 
class  MSet
 Class representing a list of search results. More...
 
class  MSetIterator
 Iterator over a Xapian::MSet. More...
 
class  MultiValueKeyMaker
 KeyMaker subclass which combines several values. More...
 
class  NetworkError
 Indicates a problem communicating with a remote database. More...
 
class  NetworkTimeoutError
 Indicates a timeout expired while communicating with a remote database. More...
 
class  NumberRangeProcessor
 Handle a number range. More...
 
class  NumberValueRangeProcessor
 Handle a number range. More...
 
class  PL2PlusWeight
 Xapian::Weight subclass implementing the PL2+ probabilistic formula. More...
 
class  PL2Weight
 This class implements the PL2 weighting scheme. More...
 
class  PositionIterator
 Class for iterating over term positions. More...
 
class  PostingIterator
 Class for iterating over a list of terms. More...
 
class  PostingSource
 Base class which provides an "external" source of postings. More...
 
class  Query
 Class representing a query. More...
 
class  QueryParser
 Build a Xapian::Query object from a user query string. More...
 
class  QueryParserError
 Indicates a query string can't be parsed. More...
 
class  RangeError
 RangeError indicates an attempt to access outside the bounds of a container. More...
 
class  RangeProcessor
 Base class for range processors. More...
 
class  Registry
 Registry for user subclasses. More...
 
class  RSet
 A relevance set (R-Set). More...
 
class  RuntimeError
 The base class for exceptions indicating errors only detectable at runtime. More...
 
class  SerialisationError
 Indicates an error in the std::string serialisation of an object. More...
 
class  SimpleStopper
 Simple implementation of Stopper class - this will suit most users. More...
 
class  Stem
 Class representing a stemming algorithm. More...
 
class  StemImplementation
 Class representing a stemming algorithm implementation. More...
 
class  Stopper
 Base class for stop-word decision functor. More...
 
class  StringValueRangeProcessor
 Handle a string range. More...
 
class  TermGenerator
 Parses a piece of text and generate terms. More...
 
class  TermIterator
 Class for iterating over a list of terms. More...
 
class  TfIdfWeight
 Xapian::Weight subclass implementing the tf-idf weighting scheme. More...
 
class  TradWeight
 Xapian::Weight subclass implementing the traditional probabilistic formula. More...
 
class  UnimplementedError
 UnimplementedError indicates an attempt to use an unimplemented feature. More...
 
class  Utf8Iterator
 An iterator which returns Unicode character values from a UTF-8 encoded string. More...
 
class  ValueCountMatchSpy
 Class for counting the frequencies of values in the matching documents. More...
 
class  ValueIterator
 Class for iterating over document values. More...
 
class  ValueMapPostingSource
 A posting source which looks up weights in a map using values as the key. More...
 
class  ValuePostingSource
 A posting source which generates weights from a value slot. More...
 
class  ValueRangeProcessor
 Base class for value range processors. More...
 
class  ValueSetMatchDecider
 MatchDecider filtering results based on whether document values are in a user-defined set. More...
 
class  ValueWeightPostingSource
 A posting source which reads weights from a value slot. More...
 
class  Weight
 Abstract base class for weighting schemes. More...
 
class  WildcardError
 WildcardError indicates an error expanding a wildcarded query. More...
 
class  WritableDatabase
 This class provides read/write access to a database. More...
 

Typedefs

typedef unsigned XAPIAN_DOCID_BASE_TYPE doccount
 A count of documents. More...
 
typedef XAPIAN_DOCID_BASE_TYPE doccount_diff
 A signed difference between two counts of documents. More...
 
typedef unsigned XAPIAN_DOCID_BASE_TYPE docid
 A unique identifier for a document. More...
 
typedef double doclength
 A normalised document length. More...
 
typedef int percent
 The percentage score for a document in an MSet. More...
 
typedef unsigned XAPIAN_TERMCOUNT_BASE_TYPE termcount
 A counts of terms. More...
 
typedef XAPIAN_TERMCOUNT_BASE_TYPE termcount_diff
 A signed difference between two counts of terms. More...
 
typedef unsigned XAPIAN_TERMPOS_BASE_TYPE termpos
 A term position within a document or query.
 
typedef XAPIAN_TERMPOS_BASE_TYPE termpos_diff
 A signed difference between two term positions. More...
 
typedef unsigned timeout
 A timeout value in milliseconds. More...
 
typedef unsigned valueno
 The number for a value slot in a document. More...
 
typedef int valueno_diff
 A signed difference between two value slot numbers. More...
 
typedef double weight
 The weight of a document or term. More...
 
typedef XAPIAN_REVISION_TYPE rev
 Revision number of a database. More...
 
typedef XAPIAN_TOTALLENGTH_TYPE totallength
 The total length of all documents in a database. More...
 

Enumerations

enum  { RP_SUFFIX = 1, RP_REPEATED = 2, RP_DATE_PREFER_MDY = 4 }
 

Functions

bool operator== (const ESetIterator &a, const ESetIterator &b)
 Equality test for ESetIterator objects.
 
bool operator!= (const ESetIterator &a, const ESetIterator &b)
 Inequality test for ESetIterator objects.
 
bool operator< (const ESetIterator &a, const ESetIterator &b)
 Inequality test for ESetIterator objects.
 
bool operator> (const ESetIterator &a, const ESetIterator &b)
 Inequality test for ESetIterator objects.
 
bool operator>= (const ESetIterator &a, const ESetIterator &b)
 Inequality test for ESetIterator objects.
 
bool operator<= (const ESetIterator &a, const ESetIterator &b)
 Inequality test for ESetIterator objects.
 
ESetIterator operator+ (ESetIterator::difference_type n, const ESetIterator &it)
 Return ESetIterator it incremented by n positions. More...
 
double miles_to_metres (double miles)
 Convert from miles to metres. More...
 
double metres_to_miles (double metres)
 Convert from metres to miles. More...
 
bool operator!= (const LatLongCoordsIterator &a, const LatLongCoordsIterator &b)
 Inequality test for LatLongCoordsIterator objects.
 
bool operator== (const MSetIterator &a, const MSetIterator &b)
 Equality test for MSetIterator objects.
 
bool operator!= (const MSetIterator &a, const MSetIterator &b)
 Inequality test for MSetIterator objects.
 
bool operator< (const MSetIterator &a, const MSetIterator &b)
 Inequality test for MSetIterator objects.
 
bool operator> (const MSetIterator &a, const MSetIterator &b)
 Inequality test for MSetIterator objects.
 
bool operator>= (const MSetIterator &a, const MSetIterator &b)
 Inequality test for MSetIterator objects.
 
bool operator<= (const MSetIterator &a, const MSetIterator &b)
 Inequality test for MSetIterator objects.
 
MSetIterator operator+ (MSetIterator::difference_type n, const MSetIterator &it)
 Return MSetIterator it incremented by n positions. More...
 
bool operator== (const PositionIterator &a, const PositionIterator &b)
 Equality test for PositionIterator objects.
 
bool operator!= (const PositionIterator &a, const PositionIterator &b)
 Inequality test for PositionIterator objects.
 
bool operator== (const PostingIterator &a, const PostingIterator &b)
 Equality test for PostingIterator objects.
 
bool operator!= (const PostingIterator &a, const PostingIterator &b)
 Inequality test for PostingIterator objects.
 
const Query operator & (const Query &a, const Query &b)
 Combine two Xapian::Query objects using OP_AND. More...
 
const Query operator| (const Query &a, const Query &b)
 Combine two Xapian::Query objects using OP_OR. More...
 
const Query operator^ (const Query &a, const Query &b)
 Combine two Xapian::Query objects using OP_XOR. More...
 
const Query operator* (double factor, const Query &q)
 Scale a Xapian::Query object using OP_SCALE_WEIGHT. More...
 
const Query operator* (const Query &q, double factor)
 Scale a Xapian::Query object using OP_SCALE_WEIGHT. More...
 
const Query operator/ (const Query &q, double factor)
 Inverse-scale a Xapian::Query object using OP_SCALE_WEIGHT. More...
 
const Query operator & (const Query &a, const InvertedQuery_ &b)
 Combine two Xapian::Query objects using OP_AND_NOT. More...
 
std::string sortable_serialise (double value)
 Convert a floating point number to a string, preserving sort order. More...
 
double sortable_unserialise (const std::string &serialised)
 Convert a string encoded using sortable_serialise back to a floating point number. More...
 
bool operator== (const TermIterator &a, const TermIterator &b)
 Equality test for TermIterator objects.
 
bool operator!= (const TermIterator &a, const TermIterator &b)
 Inequality test for TermIterator objects.
 
bool operator== (const ValueIterator &a, const ValueIterator &b)
 Equality test for ValueIterator objects.
 
bool operator!= (const ValueIterator &a, const ValueIterator &b)
 Inequality test for ValueIterator objects.
 
const char * version_string ()
 Report the version string of the library which the program is linked with. More...
 
int major_version ()
 Report the major version of the library which the program is linked with. More...
 
int minor_version ()
 Report the minor version of the library which the program is linked with. More...
 
int revision ()
 Report the revision of the library which the program is linked with. More...
 

Variables

const int DB_CREATE_OR_OPEN = 0x00
 Create database if it doesn't already exist. More...
 
const int DB_CREATE_OR_OVERWRITE = 0x01
 Create database if it doesn't already exist, or overwrite if it does. More...
 
const int DB_CREATE = 0x02
 Create a new database. More...
 
const int DB_OPEN = 0x03
 Open an existing database. More...
 
const int DB_NO_SYNC = 0x04
 Don't attempt to ensure changes have hit disk. More...
 
const int DB_FULL_SYNC = 0x08
 Try to ensure changes are really written to disk. More...
 
const int DB_DANGEROUS = 0x10
 Update the database in-place. More...
 
const int DB_NO_TERMLIST = 0x20
 When creating a database, don't create a termlist table. More...
 
const int DB_RETRY_LOCK = 0x40
 If the database is already locked, retry the lock. More...
 
const int DB_BACKEND_GLASS = 0x100
 Use the glass backend. More...
 
const int DB_BACKEND_CHERT = 0x200
 Use the chert backend. More...
 
const int DB_BACKEND_STUB = 0x300
 Open a stub database file. More...
 
const int DB_BACKEND_INMEMORY = 0x400
 Use the "in memory" backend. More...
 
const int DBCHECK_SHORT_TREE = 1
 Show a short-format display of the B-tree contents. More...
 
const int DBCHECK_FULL_TREE = 2
 Show a full display of the B-tree contents. More...
 
const int DBCHECK_SHOW_FREELIST = 4
 Show the bitmap for the B-tree. More...
 
const int DBCHECK_SHOW_STATS = 8
 Show statistics for the B-tree. More...
 
const int DBCHECK_FIX = 16
 Fix problems. More...
 
const int DBCOMPACT_NO_RENUMBER = 4
 Use the same document ids in the output as in the input(s). More...
 
const int DBCOMPACT_MULTIPASS = 8
 If merging more than 3 databases, merge the postlists in multiple passes. More...
 
const int DBCOMPACT_SINGLE_FILE = 16
 Produce a single-file database. More...
 
const int DOC_ASSUME_VALID = 1
 Assume document id is valid. More...
 
const valueno BAD_VALUENO = 0xffffffff
 Reserved value to indicate "no valueno". More...
 

Detailed Description

The Xapian namespace contains public interfaces for the Xapian library.

Typedef Documentation

◆ doccount

A count of documents.

This is used to hold values such as the number of documents in a database and the frequency of a term in the database.

◆ doccount_diff

A signed difference between two counts of documents.

This is used by the Xapian classes which are STL containers of documents for "difference_type".

◆ docid

A unique identifier for a document.

Docid 0 is invalid, providing an "out of range" value which can be used to mean "not a valid document".

◆ doclength

typedef double Xapian::doclength

A normalised document length.

The normalised document length is the document length divided by the average document length in the database.

◆ percent

typedef int Xapian::percent

The percentage score for a document in an MSet.

Deprecated:
This type is deprecated as of Xapian 1.3.0 - use the standard type int instead, which should work with older Xapian too.

◆ rev

Revision number of a database.

For databases which support this, it increases with each commit.

Experimental - see https://xapian.org/docs/deprecation#experimental-features

◆ termcount

A counts of terms.

This is used to hold values such as the Within Document Frequency (wdf).

◆ termcount_diff

A signed difference between two counts of terms.

This is used by the Xapian classes which are STL containers of terms for "difference_type".

◆ termpos_diff

A signed difference between two term positions.

This is used by the Xapian classes which are STL containers of positions for "difference_type".

◆ timeout

typedef unsigned Xapian::timeout

A timeout value in milliseconds.

There are 1000 milliseconds in a second, so for example, to set a timeout of 5 seconds use 5000.

Deprecated:
This type is deprecated as of Xapian 1.3.0 - use the standard POSIX type useconds_t instead, which should work with older Xapian too.

◆ totallength

The total length of all documents in a database.

Added in Xapian 1.4.5.

◆ valueno

typedef unsigned Xapian::valueno

The number for a value slot in a document.

Value slot numbers are unsigned and (currently) a 32-bit quantity, with Xapian::BAD_VALUENO being represented by the largest possible value. Therefore value slots 0 to 0xFFFFFFFE are available for use.

◆ valueno_diff

typedef int Xapian::valueno_diff

A signed difference between two value slot numbers.

This is used by the Xapian classes which are STL containers of values for "difference_type".

◆ weight

typedef double Xapian::weight

The weight of a document or term.

Deprecated:
This type is deprecated as of Xapian 1.3.0 - use the standard C++ type double instead, which should work with older Xapian too.

Function Documentation

◆ major_version()

int Xapian::major_version ( )
inline

Report the major version of the library which the program is linked with.

This may be different to the version compiled against (given by XAPIAN_MAJOR_VERSION) if shared libraries are being used.

◆ metres_to_miles()

double Xapian::metres_to_miles ( double  metres)
inline

Convert from metres to miles.

Experimental - see https://xapian.org/docs/deprecation#experimental-features

Referenced by miles_to_metres().

◆ miles_to_metres()

double Xapian::miles_to_metres ( double  miles)
inline

Convert from miles to metres.

Experimental - see https://xapian.org/docs/deprecation#experimental-features

References metres_to_miles().

◆ minor_version()

int Xapian::minor_version ( )
inline

Report the minor version of the library which the program is linked with.

This may be different to the version compiled against (given by XAPIAN_MINOR_VERSION) if shared libraries are being used.

◆ operator &() [1/2]

const Query Xapian::operator& ( const Query a,
const Query b 
)
inline

Combine two Xapian::Query objects using OP_AND.

Referenced by operator/().

◆ operator &() [2/2]

const Query Xapian::operator& ( const Query a,
const InvertedQuery_ &  b 
)
inline

Combine two Xapian::Query objects using OP_AND_NOT.

E.g. Xapian::Query q = q1 &~ q2;

◆ operator*() [1/2]

const Query Xapian::operator* ( double  factor,
const Query q 
)
inline

◆ operator*() [2/2]

const Query Xapian::operator* ( const Query q,
double  factor 
)
inline

Scale a Xapian::Query object using OP_SCALE_WEIGHT.

Parameters
qXapian::Query object.
factorNon-negative real number to multiply weights by.

◆ operator+() [1/2]

ESetIterator Xapian::operator+ ( ESetIterator::difference_type  n,
const ESetIterator it 
)
inline

Return ESetIterator it incremented by n positions.

If n is negative, decrements by (-n) positions.

◆ operator+() [2/2]

MSetIterator Xapian::operator+ ( MSetIterator::difference_type  n,
const MSetIterator it 
)
inline

Return MSetIterator it incremented by n positions.

If n is negative, decrements by (-n) positions.

◆ operator/()

const Query Xapian::operator/ ( const Query q,
double  factor 
)
inline

Inverse-scale a Xapian::Query object using OP_SCALE_WEIGHT.

Parameters
factorPositive real number to divide weights by.
qXapian::Query object.

References operator &().

◆ operator^()

const Query Xapian::operator^ ( const Query a,
const Query b 
)
inline

Combine two Xapian::Query objects using OP_XOR.

◆ operator|()

const Query Xapian::operator| ( const Query a,
const Query b 
)
inline

Combine two Xapian::Query objects using OP_OR.

◆ revision()

int Xapian::revision ( )
inline

Report the revision of the library which the program is linked with.

This may be different to the version compiled against (given by XAPIAN_REVISION) if shared libraries are being used.

◆ sortable_serialise()

std::string Xapian::sortable_serialise ( double  value)
inline

Convert a floating point number to a string, preserving sort order.

This method converts a floating point number to a string, suitable for using as a value for numeric range restriction, or for use as a sort key.

The conversion is platform independent.

The conversion attempts to ensure that, for any pair of values supplied to the conversion algorithm, the result of comparing the original values (with a numeric comparison operator) will be the same as the result of comparing the resulting values (with a string comparison operator). On platforms which represent doubles with the precisions specified by IEEE_754, this will be the case: if the representation of doubles is more precise, it is possible that two very close doubles will be mapped to the same string, so will compare equal.

Note also that both zero and -zero will be converted to the same representation: since these compare equal, this satisfies the comparison constraint, but it's worth knowing this if you wish to use the encoding in some situation where this distinction matters.

Handling of NaN isn't (currently) guaranteed to be sensible.

Parameters
valueThe number to serialise.

References sortable_unserialise().

◆ sortable_unserialise()

double Xapian::sortable_unserialise ( const std::string &  serialised)

Convert a string encoded using sortable_serialise back to a floating point number.

This expects the input to be a string produced by sortable_serialise(). If the input is not such a string, the value returned is undefined (but no error will be thrown).

The result of the conversion will be exactly the value which was supplied to sortable_serialise() when making the string on platforms which represent doubles with the precisions specified by IEEE_754, but may be a different (nearby) value on other platforms.

Parameters
serialisedThe serialised string to decode.

Referenced by sortable_serialise().

◆ version_string()

const char* Xapian::version_string ( )
inline

Report the version string of the library which the program is linked with.

This may be different to the version compiled against (given by XAPIAN_VERSION) if shared libraries are being used.

Variable Documentation

◆ BAD_VALUENO

const valueno Xapian::BAD_VALUENO = 0xffffffff

Reserved value to indicate "no valueno".

Referenced by Xapian::QueryParser::add_valuerangeprocessor().

◆ DB_BACKEND_CHERT

const int Xapian::DB_BACKEND_CHERT = 0x200

Use the chert backend.

When opening a WritableDatabase, this means create a chert database if a new database is created. If there's an existing database (of any type) at the specified path, this flag has no effect.

When opening a Database, this flag means to only open it if it's a chert database. There's rarely a good reason to do this - it's mostly provided as equivalent functionality to Xapian::Chert::open() in Xapian 1.2.

Referenced by Xapian::Chert::open().

◆ DB_BACKEND_GLASS

const int Xapian::DB_BACKEND_GLASS = 0x100

Use the glass backend.

When opening a WritableDatabase, this means create a glass database if a new database is created. If there's an existing database (of any type) at the specified path, this flag has no effect.

When opening a Database, this flag means to only open it if it's a glass database. There's rarely a good reason to do this - it's mostly provided as equivalent functionality to that provided by the namespaced open() functions in Xapian 1.2.

◆ DB_BACKEND_INMEMORY

const int Xapian::DB_BACKEND_INMEMORY = 0x400

Use the "in memory" backend.

The filename is currently ignored when this flag is used, but an empty string should be passed to allow for future expansion.

A new empty database is created, so when creating a Database object this creates an empty read-only database - sometimes useful to avoid special casing this situation, but otherwise of limited use. It's more useful when creating a WritableDatabase object, though beware that the current inmemory backend implementation was not built for performance and scalability.

This provides an equivalent to Xapian::InMemory::open() in Xapian 1.2.

Referenced by Xapian::InMemory::open().

◆ DB_BACKEND_STUB

const int Xapian::DB_BACKEND_STUB = 0x300

Open a stub database file.

When opening a Database, this flag means to only open it if it's a stub database file. There's rarely a good reason to do this - it's mostly provided as equivalent functionality to Xapian::Auto::open_stub() in Xapian 1.2.

Referenced by Xapian::Auto::open_stub().

◆ DB_CREATE

const int Xapian::DB_CREATE = 0x02

Create a new database.

If the database already exists, an exception will be thrown.

◆ DB_CREATE_OR_OPEN

const int Xapian::DB_CREATE_OR_OPEN = 0x00

Create database if it doesn't already exist.

If no opening mode is specified, this is the default.

◆ DB_CREATE_OR_OVERWRITE

const int Xapian::DB_CREATE_OR_OVERWRITE = 0x01

Create database if it doesn't already exist, or overwrite if it does.

◆ DB_DANGEROUS

const int Xapian::DB_DANGEROUS = 0x10

Update the database in-place.

Xapian's disk-based backends use block-based storage, with copy-on-write to allow the previous revision to be searched while a new revision forms.

This option means changed blocks get written back over the top of the old version. The benefits of this are that less I/O is required during indexing, and the result of indexing is more compact. The downsides are that you can't concurrently search while indexing, transactions can't be cancelled, and if indexing ends uncleanly (i.e. without commit() or WritableDatabase's destructor being called) then the database won't be usable.

Currently all the base files will be removed upon the first modification, and new base files will be written upon commit. This prevents new readers from opening the database while it unsafe to do so, but there's not currently a mechanism in Xapian to handle notifying existing readers.

◆ DB_FULL_SYNC

const int Xapian::DB_FULL_SYNC = 0x08

Try to ensure changes are really written to disk.

Generally fsync() and similar functions only ensure that data has been sent to the drive. Modern drives have large write-back caches for performance, and a power failure could still lose data which is in the write-back cache waiting to be written.

Some platforms provide a way to ensure data has actually been written and setting DB_FULL_SYNC will attempt to do so where possible. The downside is that committing changes takes longer, and other I/O to the same disk may be delayed too.

Currently only Mac OS X is supported, and only on some filing system types

  • if not supported, Xapian will use fsync() or similar instead.

◆ DB_NO_SYNC

const int Xapian::DB_NO_SYNC = 0x04

Don't attempt to ensure changes have hit disk.

By default, Xapian ask the OS to ensure changes have hit disk (by calling fdatasync(), fsync() or similar functions). If these calls do their job, this should mean that when WritableDatabase::commit() returns, the changes are durable, but this comes at a performance cost, and if you don't mind losing changes in the case of a crash, power failure, etc, then this option can speed up indexing significantly.

◆ DB_NO_TERMLIST

const int Xapian::DB_NO_TERMLIST = 0x20

When creating a database, don't create a termlist table.

For backends which support it (currently glass), this will prevent creation of a termlist table. This saves on the disk space that would be needed to store it, and the CPU and I/O needed to update it, but some features either inherently need the termlist table, or the current implementation of them requires it.

The following probably can't be sensibly implemented without it:

And the following currently require it:

  • Enquire::matching_terms_begin() - we could record this information during the match, though it might be hard to do without a speed penalty.
  • WritableDatabase::delete_document() - we could allow this with inexact statistics (like how Lucene does).
  • WritableDatabase::replace_document() if the document exists already (again, possible with inexact statistics).
  • Currently the list of which values are used in each document is stored in the termlist table, so things like iterating the values in a document require it (which is probably reasonable since iterating the terms in a document requires it).

You can also convert an existing database to not have a termlist table by simply deleting termlist.*.

◆ DB_OPEN

const int Xapian::DB_OPEN = 0x03

Open an existing database.

If the database doesn't exist, an exception will be thrown.

◆ DB_RETRY_LOCK

const int Xapian::DB_RETRY_LOCK = 0x40

If the database is already locked, retry the lock.

By default, if the database is already locked by a writer, trying to open it again for writing will fail by throwing Xapian::DatabaseLockError. If this flag is specified, then Xapian will instead wait for the lock (indefinitely, unless it gets an error trying to do so).

◆ DBCHECK_FIX

const int Xapian::DBCHECK_FIX = 16

Fix problems.

For use with Xapian::Database::check().

Currently this is supported for chert, and will:

  • regenerate the "iamchert" file if it isn't valid (so if it is lost, you can just create it empty and then "fix problems").
  • regenerate base files (currently the algorithm for finding the root block may not work if there was a change partly written but not committed).

◆ DBCHECK_FULL_TREE

const int Xapian::DBCHECK_FULL_TREE = 2

Show a full display of the B-tree contents.

For use with Xapian::Database::check().

◆ DBCHECK_SHORT_TREE

const int Xapian::DBCHECK_SHORT_TREE = 1

Show a short-format display of the B-tree contents.

For use with Xapian::Database::check().

◆ DBCHECK_SHOW_FREELIST

const int Xapian::DBCHECK_SHOW_FREELIST = 4

Show the bitmap for the B-tree.

For use with Xapian::Database::check().

◆ DBCHECK_SHOW_STATS

const int Xapian::DBCHECK_SHOW_STATS = 8

Show statistics for the B-tree.

For use with Xapian::Database::check().

◆ DBCOMPACT_MULTIPASS

const int Xapian::DBCOMPACT_MULTIPASS = 8

If merging more than 3 databases, merge the postlists in multiple passes.

This is generally faster but requires more disk space for temporary files.

Referenced by Xapian::Compactor::set_multipass().

◆ DBCOMPACT_NO_RENUMBER

const int Xapian::DBCOMPACT_NO_RENUMBER = 4

Use the same document ids in the output as in the input(s).

By default compaction renumbers the document ids in the output database, currently by applying the same offset to all the document ids in a particular source database. If this flag is specified, then this renumbering doesn't happen, but all the document ids must be unique over all source databases. Currently the ranges of document ids in each source must not overlap either, though this restriction may be removed in the future.

Referenced by Xapian::Compactor::set_renumber().

◆ DBCOMPACT_SINGLE_FILE

const int Xapian::DBCOMPACT_SINGLE_FILE = 16

Produce a single-file database.

Only supported by the glass backend currently.

◆ DOC_ASSUME_VALID

const int Xapian::DOC_ASSUME_VALID = 1

Assume document id is valid.

By default, Database::get_document() checks that the document id passed is actually in use and throws DocNotFoundError if not. This flag can be used to disable this check - useful to save a bit of work when you know for sure that the document id is valid.

Some database backends may check anyway - the remote backend currently does.


Documentation for Xapian (version 1.4.9).
Generated on Sat Nov 3 2018 by Doxygen 1.8.13.