Class managing a Btree table in a Glass database. More...

#include <glass_table.h>

Inheritance diagram for GlassTable:

Collaboration diagram for GlassTable:

Public Member Functions
	GlassTable (const char *tablename_, const std::string &path_, bool readonly_, bool lazy=false)
	Create a new Btree object. More...

	GlassTable (const char *tablename_, int fd, off_t offset_, bool readonly_, bool lazy=false)

	~GlassTable ()
	Close the Btree. More...

void	close (bool permanent=false)
	Close the Btree. More...

bool	readahead_key (const string &key) const

bool	exists () const
	Determine whether the btree exists on disk. More...

void	open (int flags_, const RootInfo &root_info, glass_revision_number_t rev)
	Open the btree. More...

bool	is_open () const
	Return true if this table is open. More...

bool	is_writable () const
	Return true if this table is writable. More...

void	flush_db ()
	Flush any outstanding changes to the DB file of the table. More...

void	commit (glass_revision_number_t revision, RootInfo *root_info)
	Commit any outstanding changes to the table. More...

bool	sync ()

void	cancel (const RootInfo &root_info, glass_revision_number_t rev)
	Cancel any outstanding changes. More...

bool	get_exact_entry (const std::string &key, std::string &tag) const
	Read an entry from the table, if and only if it is exactly that being asked for. More...

bool	key_exists (const std::string &key) const
	Check if a key exists in the Btree. More...

bool	read_tag (Glass::Cursor C_, std::string tag, bool keep_compressed) const
	Read the tag value for the key pointed to by cursor C_. More...

void	add (const std::string &key, const std::string &tag, bool already_compressed=false)
	Add a key/tag pair to the table, replacing any existing pair with the same key. More...

bool	del (const std::string &key)
	Delete an entry from the table. More...

int	get_flags () const

void	create_and_open (int flags_, const RootInfo &root_info)
	Create a new empty btree structure on disk and open it at the initial revision. More...

void	set_full_compaction (bool parity)

glass_revision_number_t	get_open_revision_number () const
	Get the revision number at which this table is currently open. More...

glass_tablesize_t	get_entry_count () const
	Return a count of the number of entries in the table. More...

bool	empty () const
	Return true if there are no entries in the table. More...

GlassCursor *	cursor_get () const
	Get a cursor for reading from the table. More...

bool	is_modified () const
	Determine whether the object contains uncommitted modifications. More...

void	set_max_item_size (size_t block_capacity)
	Set the maximum item size given the block capacity. More...

void	set_changes (GlassChanges *changes)
	Set the GlassChanges object to write changed blocks to. More...

string	get_path () const

Static Public Member Functions
static void	throw_database_closed ()
	Throw an exception indicating that the database is closed. More...

Protected Member Functions
bool	find (Glass::Cursor *) const
	find(C_) searches for the key of B->kt in the B-tree. More...

int	delete_kt ()

void	read_block (uint4 n, uint8_t *p) const
	read_block(n, p) reads block n of the DB file to address p. More...

void	write_block (uint4 n, const uint8_t *p, bool appending=false) const
	write_block(n, p, appending) writes block n in the DB file from address p. More...

void	set_overwritten () const

void	block_to_cursor (Glass::Cursor *C_, int j, uint4 n) const

void	alter ()
	Btree::alter(); is called when the B-tree is to be altered. More...

void	compact (uint8_t *p)
	compact(p) compact the block at p by shuffling all the items up to the end. More...

void	enter_key_above_leaf (Glass::LeafItem previtem, Glass::LeafItem newitem)
	enter_key_above_leaf(previtem, newitem) is called after a leaf block split. More...

void	enter_key_above_branch (int j, Glass::BItem newitem)
	enter_key_above_branch(j, newkey) is called after a branch block split. More...

int	mid_point (uint8_t *p) const
	mid_point(p) finds the directory entry in c that determines the approximate mid point of the data in the block at p. More...

void	add_item_to_leaf (uint8_t *p, Glass::LeafItem kt, int c)
	add_item_to_leaf(p, kt_, c) adds item kt_ to the leaf block at p. More...

void	add_item_to_branch (uint8_t *p, Glass::BItem kt, int c)
	add_item_to_branch(p, kt_, c) adds item kt_ to the branch block at p. More...

void	add_leaf_item (Glass::LeafItem kt)
	GlassTable::add_leaf_item(kt_) adds item kt_ to the leaf block. More...

void	add_branch_item (Glass::BItem kt, int j)
	GlassTable::add_item(kt_, j) adds item kt_ to the block at cursor level C[j]. More...

void	delete_leaf_item (bool repeatedly)
	GlassTable::delete_leaf_item(repeatedly) is (almost) the converse of add_leaf_item. More...

void	delete_branch_item (int j)
	GlassTable::delete_branch_item(j, repeatedly) is (almost) the converse of add_branch_item. More...

int	add_kt (bool found)
	add_kt(found) adds the item (key-tag pair) at B->kt into the B-tree, using cursor C. More...

void	read_root ()

void	split_root (uint4 split_n)
	Btree needs to gain a new level to insert more items: so split root block and construct a new one. More...

void	form_key (const std::string &key) const

bool	single_file () const

bool	prev (Glass::Cursor *C_, int j) const

bool	next (Glass::Cursor *C_, int j) const

bool	prev_default (Glass::Cursor *C_, int j) const

bool	next_default (Glass::Cursor *C_, int j) const

bool	prev_for_sequential (Glass::Cursor *C_, int dummy) const

bool	next_for_sequential (Glass::Cursor *C_, int dummy) const

Static Protected Member Functions
static int	find_in_leaf (const uint8_t *p, Glass::LeafItem item, int c, bool &exact)
	find_in_leaf(p, key, c, exact) searches for the key in the leaf block at p. More...

static int	find_in_branch (const uint8_t *p, Glass::LeafItem item, int c)

static int	find_in_branch (const uint8_t *p, Glass::BItem item, int c)

static uint4	block_given_by (const uint8_t *p, int c)
	block_given_by(p, c) finds the item at block address p, directory offset c, and returns its tag value as an integer. More...

Protected Attributes
const char *	tablename
	The name of the table (used when writing changesets). More...

glass_revision_number_t	revision_number
	revision number of the opened B-tree. More...

glass_tablesize_t	item_count
	keeps a count of the number of items in the B-tree. More...

unsigned int	block_size
	block size of the B tree in bytes More...

int	flags
	Flags like DB_NO_SYNC and DB_DANGEROUS. More...

bool	faked_root_block
	true if the root block is faked (not written to disk). More...

bool	sequential
	true iff the data has been written in a single write in sequential order. More...

int	handle
	File descriptor of the table. More...

int	level
	number of levels, counting from 0 More...

uint4	root
	the root block of the B-tree More...

Glass::LeafItem_wr	kt
	buffer of size block_size for making up key-tag items More...

uint8_t *	buffer
	buffer of size block_size for reforming blocks More...

GlassFreeList	free_list
	List of free blocks. More...

std::string	name
	The path name of the B tree. More...

int	seq_count
	count of the number of successive instances of purely sequential addition, starting at SEQ_START_POINT (neg) and going up to zero. More...

uint4	changed_n
	the last block to be changed by an addition More...

int	changed_c
	directory offset corresponding to last block to be changed by an addition More...

size_t	max_item_size
	maximum size of an item (key-tag pair) More...

bool	Btree_modified
	Set to true the first time the B-tree is modified. More...

bool	full_compaction
	set to true when full compaction is to be achieved More...

bool	writable
	Set to true when the database is opened to write. More...

bool	cursor_created_since_last_modification
	Flag for tracking when cursors need to rebuild. More...

unsigned long	cursor_version
	Version count for tracking when cursors need to rebuild. More...

GlassChanges *	changes_obj
	The GlassChanges object to write block changes to. More...

Glass::Cursor	C [GLASS_BTREE_CURSOR_LEVELS]

uint8_t *	split_p
	Buffer used when splitting a block. More...

uint4	compress_min
	Minimum size tag to try compressing (0 for no compression). More...

CompressionStream	comp_stream

bool	lazy
	If true, don't create the table until it's needed. More...

uint4	last_readahead
	Last block readahead_key() preread. More...

off_t	offset
	offset to start of table in file. More...

Private Member Functions
	GlassTable (const GlassTable &)
	Copying not allowed. More...

GlassTable &	operator= (const GlassTable &)
	Assignment not allowed. More...

void	basic_open (const RootInfo *root_info, glass_revision_number_t rev)

void	do_open_to_read (const RootInfo *root_info, glass_revision_number_t rev)
	Perform the opening operation to read. More...

void	do_open_to_write (const RootInfo *root_info, glass_revision_number_t rev=0)
	Perform the opening operation to write. More...

Friends
class	GlassCursor

class	GlassFreeList

Detailed Description

Class managing a Btree table in a Glass database.

A table is a store holding a set of key/tag pairs.

A key is used to access a block of data in a glass table.

Keys are of limited length.

Keys may not be empty (each Btree has a special empty key for internal use).

A tag is a piece of data associated with a given key. The contents of the tag are opaque to the Btree.

Tags may be of arbitrary length (the Btree imposes a very large limit). Note though that they will be loaded into memory in their entirety, so should not be permitted to grow without bound in normal usage.

Tags which are null strings are valid, and are different from a tag simply not being in the table.

Definition at line 425 of file glass_table.h.

Constructor & Destructor Documentation

◆ GlassTable() [1/3]

GlassTable::GlassTable ( const GlassTable & )

private

Copying not allowed.

◆ GlassTable() [2/3]

GlassTable::GlassTable	(	const char *	tablename_,
		const std::string &	path_,
		bool	readonly_,
		bool	lazy = `false`
	)

Create a new Btree object.

This does not create the table on disk - the create_and_open() method must be called to create the table on disk.

This also does not open the table - either the create_and_open() or open() methods must be called before use is made of the table.

Parameters

tablename_	The name of the table (used in changesets).
path_	Path at which the table is stored.
readonly_	whether to open the table for read only access.
lazy	If true, don't create the table until it's needed.

Definition at line 1698 of file glass_table.cc.

References LOGCALL_CTOR.

◆ GlassTable() [3/3]

GlassTable::GlassTable	(	const char *	tablename_,
		int	fd,
		off_t	offset_,
		bool	readonly_,
		bool	lazy = `false`
	)

Definition at line 1733 of file glass_table.cc.

References LOGCALL_CTOR.

◆ ~GlassTable()

GlassTable::~GlassTable ( )

Close the Btree.

Any outstanding changes (ie, changes made without commit() having subsequently been called) will be lost.

Definition at line 1807 of file glass_table.cc.

References close(), and LOGCALL_DTOR.

Member Function Documentation

◆ add()

void GlassTable::add	(	const std::string &	key,
		const std::string &	tag,
		bool	already_compressed = `false`
	)

Add a key/tag pair to the table, replacing any existing pair with the same key.

If an error occurs during the operation, an exception will be thrown.

If key is empty, then the null item is replaced.

e.g. btree.add("TODAY", "Mon 9 Oct 2000");

Parameters

key	The key to store in the table.
tag	The tag to store in the table.
already_compressed	true if tag is already compressed, for example because it is being opaquely copied (default: false).

Definition at line 1279 of file glass_table.cc.

References Assert, AssertEq, BYTE_PAIR_RANGE, C, Glass::D2, Glass::I2, Glass::RootInfo::init(), Glass::K1, LOGCALL_VOID, throw_database_closed(), Glass::TOTAL_FREE(), and Glass::X2.

Referenced by GlassDocDataTable::add_document_data(), Glass::PostlistChunkWriter::flush(), GlassCompact::merge_docid_keyed(), GlassCompact::merge_positions(), GlassCompact::merge_postlists(), GlassCompact::merge_spellings(), GlassCompact::merge_synonyms(), GlassDocDataTable::replace_document_data(), GlassWritableDatabase::set_metadata(), and Glass::ValueUpdater::write_tag().

◆ add_branch_item()

void GlassTable::add_branch_item	(	Glass::BItem	kt,
		int	j
	)

protected

GlassTable::add_item(kt_, j) adds item kt_ to the block at cursor level C[j].

If there is not enough room the block splits and the item is then added to the appropriate half.

Definition at line 942 of file glass_table.cc.

References Assert, AssertRel, Glass::BItem_base< T >::block_given_by(), C, Glass::D2, Glass::DIR_END(), Glass::DIR_START, Glass::BItem_wr::form_null_key(), Glass::BItem_base< T >::key(), Glass::Key::length(), LOGCALL_VOID, Glass::MAX_FREE(), Glass::SET_DIR_END(), Glass::SET_TOTAL_FREE(), Glass::BItem_base< T >::size(), and Glass::TOTAL_FREE().

◆ add_item_to_branch()

void GlassTable::add_item_to_branch	(	uint8_t *	p,
		Glass::BItem	kt,
		int	c
	)

protected

add_item_to_branch(p, kt_, c) adds item kt_ to the branch block at p.

c is the offset in the directory that needs to be expanded to accommodate the new entry for the item. We know before this is called that there is enough contiguous room for the item in the block, so it's just a matter of shuffling up any directory entries after where we're inserting and copying in the item.

Definition at line 811 of file glass_table.cc.

References Assert, AssertRel, Glass::D2, Glass::DIR_END(), Glass::DIR_START, Glass::BItem_base< T >::get_address(), LOGCALL_VOID, Glass::MAX_FREE(), Glass::SET_DIR_END(), Glass::SET_MAX_FREE(), Glass::SET_TOTAL_FREE(), Glass::BItem_wr::setD(), Glass::BItem_base< T >::size(), and Glass::TOTAL_FREE().

◆ add_item_to_leaf()

void GlassTable::add_item_to_leaf	(	uint8_t *	p,
		Glass::LeafItem	kt,
		int	c
	)

protected

add_item_to_leaf(p, kt_, c) adds item kt_ to the leaf block at p.

c is the offset in the directory that needs to be expanded to accommodate the new entry for the item. We know before this is called that there is enough contiguous room for the item in the block, so it's just a matter of shuffling up any directory entries after where we're inserting and copying in the item.

Definition at line 771 of file glass_table.cc.

References Assert, AssertRel, Glass::D2, Glass::DIR_END(), Glass::DIR_START, Glass::LeafItem_base< T >::get_address(), LOGCALL_VOID, Glass::MAX_FREE(), Glass::SET_DIR_END(), Glass::SET_MAX_FREE(), Glass::SET_TOTAL_FREE(), Glass::LeafItem_wr::setD(), Glass::LeafItem_base< T >::size(), and Glass::TOTAL_FREE().

◆ add_kt()

int GlassTable::add_kt ( bool found )

protected

add_kt(found) adds the item (key-tag pair) at B->kt into the B-tree, using cursor C.

found == find() is handed over as a parameter from Btree::add. Btree::alter() prepares for the alteration to the B-tree. Then there are a number of cases to consider:

If an item with the same key is in the B-tree (found is true), the new kt replaces it.

If then kt is smaller, or the same size as, the item it replaces, kt is put in the same place as the item it replaces, and the TOTAL_FREE measure is reduced.

If kt is larger than the item it replaces it is put in the MAX_FREE space if there is room, and the directory entry and space counts are adjusted accordingly.

But if there is not room we do it the long way: the old item is deleted with delete_leaf_item and kt is added in with add_item.

If the key of kt is not in the B-tree (found is false), the new kt is added in with add_item.

Returns: 0 : added kt 1 : replaced kt 2 : replaced kt and it was the final one

Definition at line 1149 of file glass_table.cc.

References Assert, AssertRel, C, Glass::D2, Glass::DIR_END(), Glass::DIR_START, Glass::LeafItem_base< T >::get_address(), Glass::LeafItem_base< T >::last_component(), LOGCALL, Glass::MAX_FREE(), RETURN, SEQ_START_POINT, Glass::SET_MAX_FREE(), Glass::SET_TOTAL_FREE(), Glass::LeafItem_wr::setD(), Glass::LeafItem_base< T >::size(), and Glass::TOTAL_FREE().

◆ add_leaf_item()

void GlassTable::add_leaf_item ( Glass::LeafItem kt )

protected

GlassTable::add_leaf_item(kt_) adds item kt_ to the leaf block.

If there is not enough room the block splits and the item is then added to the appropriate half.

Definition at line 847 of file glass_table.cc.

References Assert, AssertRel, C, Glass::D2, Glass::DIR_END(), Glass::DIR_START, LOGCALL_VOID, Glass::MAX_FREE(), Glass::SET_DIR_END(), Glass::LeafItem_base< T >::size(), and Glass::TOTAL_FREE().

◆ alter()

void GlassTable::alter ( )

protected

Btree::alter(); is called when the B-tree is to be altered.

It causes new blocks to be forced for the current set of blocks in the cursor.

The point is that if a block at level 0 is to be altered it may get a new number. Then the pointer to this block from level 1 will need changing. So the block at level 1 needs altering and may get a new block number. Then the pointer to this block from level 2 will need changing ... and so on back to the root.

The clever bit here is spotting the cases when we can make an early exit from this process. If C[j].rewrite is true, C[j+k].rewrite will be true for k = 1,2 ... We have been through all this before, and there is no need to do it again. If C[j].n was free at the start of the transaction, we can copy it back to the same place without violating the integrity of the B-tree. We don't then need a new n and can return. The corresponding C[j].rewrite may be true or false in that case.

Definition at line 374 of file glass_table.cc.

References Assert, C, Xapian::DB_DANGEROUS, LOGCALL_VOID, Glass::REVISION(), Glass::BItem_wr::set_block_given_by(), and Glass::SET_REVISION().

◆ basic_open()

void GlassTable::basic_open	(	const RootInfo *	root_info,
		glass_revision_number_t	rev
	)

private

Definition at line 1577 of file glass_table.cc.

References Glass::BLOCK_CAPACITY, C, Glass::RootInfo::get_compress_min(), Glass::RootInfo::get_free_list(), Glass::RootInfo::get_level(), Glass::RootInfo::get_num_entries(), Glass::RootInfo::get_root(), Glass::RootInfo::get_root_is_fake(), Glass::RootInfo::get_sequential(), LOGCALL_VOID, and zeroed_new().

Referenced by do_open_to_read().

◆ block_given_by()

static uint4 GlassTable::block_given_by	(	const uint8_t *	p,
		int	c
	)

staticprotected

block_given_by(p, c) finds the item at block address p, directory offset c, and returns its tag value as an integer.

Referenced by next_default(), and prev_default().

◆ block_to_cursor()

void GlassTable::block_to_cursor	(	Glass::Cursor *	C_,
		int	j,
		uint4	n
	)		const

protected

Definition at line 310 of file glass_table.cc.

References Assert, C, Glass::Cursor::clone(), Glass::GET_LEVEL(), Glass::Cursor::init(), LOGCALL_VOID, rare, Glass::REVISION(), Glass::Cursor::rewrite, Glass::Cursor::set_n(), and Xapian::Internal::str().

Referenced by next_default(), and prev_default().

◆ cancel()

void GlassTable::cancel	(	const RootInfo &	root_info,
		glass_revision_number_t	rev
	)

Cancel any outstanding changes.

This will discard any modifications which haven't been committed by calling commit().

Definition at line 1927 of file glass_table.cc.

References Assert, block_size, Btree_modified, C, changed_c, changed_n, cursor_created_since_last_modification, cursor_version, Xapian::DB_DANGEROUS, DIR_START, faked_root_block, flags, free_list, Glass::RootInfo::get_blocksize(), Glass::RootInfo::get_free_list(), Glass::RootInfo::get_level(), Glass::RootInfo::get_num_entries(), Glass::RootInfo::get_root(), Glass::RootInfo::get_root_is_fake(), Glass::RootInfo::get_sequential(), handle, Glass::Cursor::init(), item_count, level, LOGCALL_VOID, read_root(), GlassFreeList::reset(), revision_number, Glass::Cursor::rewrite, root, seq_count, SEQ_START_POINT, sequential, throw_database_closed(), GlassFreeList::unpack(), and writable.

Referenced by GlassSynonymTable::cancel(), GlassSpellingTable::cancel(), and GlassDatabase::cancel().

◆ close()

void GlassTable::close ( bool permanent = false )

Close the Btree.

This closes and frees any of the btree structures which have been created and opened.

Parameters

permanent If true, the Btree will not reopen on demand.

Definition at line 1812 of file glass_table.cc.

References buffer, C, Glass::Cursor::destroy(), Glass::LeafItem_base< T >::get_address(), handle, kt, level, LOGCALL_VOID, single_file(), and split_p.

Referenced by GlassDatabase::close(), commit(), create_and_open(), open(), and ~GlassTable().

◆ commit()

void GlassTable::commit	(	glass_revision_number_t	revision,
		RootInfo *	root_info
	)

Commit any outstanding changes to the table.

Commit changes made by calling add() and del() to the Btree.

If an error occurs during the operation, this will be signalled by an exception. In case of error, changes made will not be committed to the Btree - they will be discarded.

Parameters

new_revision	The new revision number to store. This must be greater than the current revision number. FIXME: If we support rewinding to a previous revision, maybe this needs to be greater than any previously used revision.
root_info	Information about the root is returned in this.

Definition at line 1866 of file glass_table.cc.

References Assert, block_size, Btree_modified, C, changed_c, changed_n, close(), GlassFreeList::commit(), DIR_START, faked_root_block, free_list, Glass::Cursor::get_n(), handle, Glass::Cursor::init(), item_count, level, LOGCALL_VOID, GlassFreeList::pack(), read_root(), Xapian::revision(), revision_number, root, seq_count, SEQ_START_POINT, sequential, Glass::RootInfo::set_blocksize(), Glass::RootInfo::set_free_list(), Glass::RootInfo::set_level(), Glass::RootInfo::set_num_entries(), GlassFreeList::set_revision(), Glass::RootInfo::set_root(), Glass::RootInfo::set_root_is_fake(), Glass::RootInfo::set_sequential(), throw_database_closed(), and writable.

Referenced by GlassDatabase::compact(), GlassCompact::multimerge_postlists(), and GlassDatabase::set_revision_number().

◆ compact()

void GlassTable::compact ( uint8_t * p )

protected

compact(p) compact the block at p by shuffling all the items up to the end.

MAX_FREE(p) is then maximized, and is equal to TOTAL_FREE(p).

Definition at line 563 of file glass_table.cc.

References Assert, Glass::D2, Glass::DIR_END(), Glass::DIR_START, Glass::LeafItem_base< T >::get_address(), Glass::BItem_base< T >::get_address(), Glass::GET_LEVEL(), LOGCALL_VOID, Glass::SET_MAX_FREE(), Glass::SET_TOTAL_FREE(), Glass::LeafItem_wr::setD(), Glass::BItem_wr::setD(), Glass::LeafItem_base< T >::size(), and Glass::BItem_base< T >::size().

◆ create_and_open()

void GlassTable::create_and_open	(	int	flags_,
		const RootInfo &	root_info
	)

Create a new empty btree structure on disk and open it at the initial revision.

The table must be writable - it doesn't make sense to create a table that is read-only!

The block size must be less than 64K, where K = 1024. It is unwise to use a small block size (less than 1024 perhaps), so we enforce a minimum block size of 2K.

Example:

// File will be "X." + GLASS_TABLE_EXTENSION (i.e. "X.glass") Btree btree("X."); btree.create_and_open(0, root_info);

Parameters

root_info RootInfo object

Exceptions

Xapian::DatabaseCreateError	if the table can't be created.
Xapian::InvalidArgumentError	if the requested blocksize is unsuitable.

Definition at line 1776 of file glass_table.cc.

References Assert, block_size, BYTE_PAIR_RANGE, close(), compress_min, do_open_to_write(), flags, Glass::RootInfo::get_blocksize(), Glass::RootInfo::get_compress_min(), GLASS_TABLE_EXTENSION, handle, io_unlink(), lazy, LOGCALL_VOID, throw_database_closed(), and writable.

Referenced by GlassDatabase::compact(), GlassDatabase::create_and_open_tables(), and GlassCompact::multimerge_postlists().

◆ cursor_get()

GlassCursor * GlassTable::cursor_get ( ) const

Get a cursor for reading from the table.

The cursor is owned by the caller - it is the caller's responsibility to ensure that it is deleted.

Definition at line 1562 of file glass_table.cc.

References LOGCALL, RETURN, and throw_database_closed().

Referenced by Glass::PostlistChunkWriter::flush(), GlassDatabase::get_postlist_cursor(), GlassAllTermsList::next(), GlassDatabase::open_metadata_keylist(), GlassDatabase::open_spelling_wordlist(), GlassDatabase::open_synonym_keylist(), GlassPositionList::read_data(), GlassAllTermsList::skip_to(), and Glass::ValueUpdater::update().

◆ del()

bool GlassTable::del ( const std::string & key )

Delete an entry from the table.

The entry will be removed from the table, if it exists. If it does not exist, no action will be taken. The item with an empty key can't be removed, and false is returned.

If an error occurs during the operation, this will be signalled by an exception.

e.g. bool deleted = btree.del("TODAY")

Parameters

key	The key to remove from the table.

Returns: true if an entry was removed; false if it did not exist.

Definition at line 1394 of file glass_table.cc.

References Assert, GLASS_BTREE_MAX_KEY_LEN, LOGCALL, RETURN, and throw_database_closed().

Referenced by GlassDocDataTable::delete_document_data(), Glass::PostlistChunkWriter::flush(), GlassWritableDatabase::set_metadata(), and Glass::ValueUpdater::write_tag().

◆ delete_branch_item()

void GlassTable::delete_branch_item ( int j )

protected

GlassTable::delete_branch_item(j, repeatedly) is (almost) the converse of add_branch_item.

The process repeats at the next level when a block has been completely emptied, freeing the block and taking out the pointer to it. Emptied root blocks are also removed, which reduces the number of levels in the B-tree.

Definition at line 1074 of file glass_table.cc.

References Assert, AssertRel, BLK_UNUSED, Glass::BItem_base< T >::block_given_by(), C, Glass::D2, Glass::DIR_END(), Glass::DIR_START, LOGCALL_VOID, Glass::MAX_FREE(), Glass::SET_DIR_END(), Glass::SET_MAX_FREE(), Glass::SET_TOTAL_FREE(), Glass::BItem_base< T >::size(), and Glass::TOTAL_FREE().

◆ delete_kt()

int GlassTable::delete_kt ( )

protected

Definition at line 1222 of file glass_table.cc.

References Assert, C, Glass::LeafItem_base< T >::last_component(), LOGCALL, RETURN, and SEQ_START_POINT.

◆ delete_leaf_item()

void GlassTable::delete_leaf_item ( bool repeatedly )

protected

GlassTable::delete_leaf_item(repeatedly) is (almost) the converse of add_leaf_item.

If repeatedly is true, the process repeats at the next level when a block has been completely emptied, freeing the block and taking out the pointer to it. Emptied root blocks are also removed, which reduces the number of levels in the B-tree.

Definition at line 1039 of file glass_table.cc.

References Assert, AssertRel, BLK_UNUSED, C, Glass::D2, Glass::DIR_END(), Glass::DIR_START, LOGCALL_VOID, Glass::MAX_FREE(), Glass::SET_DIR_END(), Glass::SET_MAX_FREE(), Glass::SET_TOTAL_FREE(), Glass::LeafItem_base< T >::size(), and Glass::TOTAL_FREE().

◆ do_open_to_read()

void GlassTable::do_open_to_read	(	const RootInfo *	root_info,
		glass_revision_number_t	rev
	)

private

Perform the opening operation to read.

Definition at line 1980 of file glass_table.cc.

References basic_open(), GLASS_TABLE_EXTENSION, handle, io_open_block_rd(), lazy, LOGCALL, name, read_root(), revision_number, single_file(), and throw_database_closed().

Referenced by open().

◆ do_open_to_write()

void GlassTable::do_open_to_write	(	const RootInfo *	root_info,
		glass_revision_number_t	rev = `0`
	)

private

Perform the opening operation to write.

Definition at line 1659 of file glass_table.cc.

References Glass::DIR_START, GLASS_TABLE_EXTENSION, io_open_block_wr(), LOGCALL_VOID, name, SEQ_START_POINT, throw_database_closed(), and zeroed_new().

Referenced by create_and_open(), and open().

◆ empty()

bool GlassTable::empty ( ) const

inline

Return true if there are no entries in the table.

Definition at line 681 of file glass_table.h.

Referenced by GlassDatabase::compact(), GlassDatabase::has_positions(), main(), GlassCompact::merge_docid_keyed(), GlassCompact::merge_positions(), GlassCompact::merge_postlists(), GlassCompact::merge_spellings(), and GlassCompact::merge_synonyms().

◆ enter_key_above_branch()

void GlassTable::enter_key_above_branch	(	int	j,
		Glass::BItem	newitem
	)

protected

enter_key_above_branch(j, newkey) is called after a branch block split.

It enters in the block at level C[j] a separating key for the block at level C[j - 1]. The key itself is newkey.

This code looks longer than it really is. If j exceeds the number of B-tree levels the root block has split and we have to construct a new one, but this is a rare event.

The key is constructed in b, with block number C[j - 1].n as tag, and this is added in with add_item. add_item may itself cause a block split, with a further call to enter_key. Hence the recursion.

Definition at line 703 of file glass_table.cc.

References Assert, AssertEq, AssertRel, Glass::BYTES_PER_BLOCK_NUMBER, C, Glass::D2, Glass::K1, Glass::BItem_base< T >::key(), LOGCALL_VOID, Glass::BItem_wr::set_key_and_block(), and Glass::X2.

◆ enter_key_above_leaf()

void GlassTable::enter_key_above_leaf	(	Glass::LeafItem	previtem,
		Glass::LeafItem	newitem
	)

protected

enter_key_above_leaf(previtem, newitem) is called after a leaf block split.

It enters in the block at level C[1] a separating key for the block at level C[0]. The key itself is newitem.key(). previtem is the preceding item, and at level 1 newitem.key() can be trimmed down to the first point of difference to previtem.key() for entry in C[j].

This code looks longer than it really is. If j exceeds the number of B-tree levels the root block has split and we have to construct a new one, but this is a rare event.

The key is constructed in b, with block number C[0].n as tag, and this is added in with add_item. add_item may itself cause a block split, with a further call to enter_key. Hence the recursion.

Definition at line 647 of file glass_table.cc.

References Assert, AssertEq, AssertRel, Glass::BYTES_PER_BLOCK_NUMBER, C, Glass::compare(), Glass::LeafItem_base< T >::component_of(), Glass::D2, Glass::K1, Glass::LeafItem_base< T >::key(), Glass::Key::length(), LOGCALL_VOID, Glass::BItem_wr::set_truncated_key_and_block(), and Glass::X2.

◆ exists()

bool GlassTable::exists ( ) const

Determine whether the btree exists on disk.

Definition at line 1769 of file glass_table.cc.

References file_exists(), GLASS_TABLE_EXTENSION, LOGCALL, and single_file().

Referenced by GlassDatabase::database_exists().

◆ find()

bool GlassTable::find ( Glass::Cursor * C_ ) const

protected

find(C_) searches for the key of B->kt in the B-tree.

Result is true if found, false otherwise. When false, the B_tree cursor is positioned at the last key in the B-tree <= the search key. Goes to first (null) item in B-tree when key length == 0.

Definition at line 530 of file glass_table.cc.

References LOGCALL, and RETURN.

◆ find_in_branch() [1/2]

int GlassTable::find_in_branch	(	const uint8_t *	p,
		Glass::LeafItem	item,
		int	c
	)

staticprotected

Definition at line 509 of file glass_table.cc.

References find_in_branch_(), Glass::LeafItem_base< T >::get_address(), LOGCALL_STATIC, and RETURN.

◆ find_in_branch() [2/2]

int GlassTable::find_in_branch	(	const uint8_t *	p,
		Glass::BItem	item,
		int	c
	)

staticprotected

Definition at line 516 of file glass_table.cc.

References find_in_branch_(), Glass::BItem_base< T >::get_address(), LOGCALL_STATIC, and RETURN.

◆ find_in_leaf()

int GlassTable::find_in_leaf	(	const uint8_t *	p,
		Glass::LeafItem	item,
		int	c,
		bool &	exact
	)

staticprotected

find_in_leaf(p, key, c, exact) searches for the key in the leaf block at p.

What we get is the directory entry to the last key <= the key being searched for.

The lookup is by binary chop, with i and j set to the left and right ends of the search area. In sequential addition, c will often be the answer, so we test the keys round c and move i and j towards c if possible.

exact is set to true if the match was exact (otherwise exact is unchanged).

Definition at line 418 of file glass_table.cc.

References Assert, AssertRel, Glass::compare(), Glass::D2, Glass::DIR_END(), Glass::DIR_START, Glass::LeafItem_base< T >::get_address(), LOGCALL_STATIC, and RETURN.

◆ flush_db()

void GlassTable::flush_db ( )

Flush any outstanding changes to the DB file of the table.

This must be called before commit, to ensure that the DB file is ready to be switched to a new version by the commit.

Definition at line 1845 of file glass_table.cc.

References Assert, C, faked_root_block, handle, level, LOGCALL_VOID, throw_database_closed(), writable, and write_block().

Referenced by GlassDatabase::compact(), GlassSynonymTable::flush_db(), GlassSpellingTable::flush_db(), GlassCompact::multimerge_postlists(), and GlassDatabase::set_revision_number().

◆ form_key()

void GlassTable::form_key ( const std::string & key ) const

protected

Definition at line 1249 of file glass_table.cc.

References LOGCALL_VOID.

◆ get_entry_count()

glass_tablesize_t GlassTable::get_entry_count ( ) const

inline

Return a count of the number of entries in the table.

The count does not include the ever-present item with null key.

Use empty() if you only want to know if the table is empty or not.

Returns: The number of entries in the table.

Definition at line 676 of file glass_table.h.

Referenced by Inverter::has_positions(), and main().

◆ get_exact_entry()

bool GlassTable::get_exact_entry	(	const std::string &	key,
		std::string &	tag
	)		const

Read an entry from the table, if and only if it is exactly that being asked for.

If the key is found in the table, then the tag is copied to tag. If the key is not found tag is left unchanged.

The result is true iff the specified key is found in the Btree.

Parameters

key	The key to look for in the table.
tag	A tag object to fill with the value if found.

Returns: true if key is found in table, false if key is not found in table.

Definition at line 1473 of file glass_table.cc.

References Assert, C, GLASS_BTREE_MAX_KEY_LEN, LOGCALL, RETURN, and throw_database_closed().

Referenced by Glass::PostlistChunkWriter::flush(), GlassDocDataTable::get_document_data(), GlassPostListTable::get_freqs(), GlassDatabase::get_metadata(), GlassTermList::GlassTermList(), and Inverter::store_positions().

◆ get_flags()

int GlassTable::get_flags ( ) const

inline

Definition at line 626 of file glass_table.h.

Referenced by GlassDatabase::apply(), GlassDatabase::modifications_failed(), and GlassDatabase::reopen().

◆ get_open_revision_number()

glass_revision_number_t GlassTable::get_open_revision_number ( ) const

inline

Get the revision number at which this table is currently open.

It is possible that there are other, more recent or older revisions available.

Returns: the current revision number.

Definition at line 663 of file glass_table.h.

◆ get_path()

string GlassTable::get_path ( ) const

inline

Definition at line 728 of file glass_table.h.

References GLASS_TABLE_EXTENSION, Glass::Key::p, GlassFreeList::read_block(), and GlassFreeList::write_block().

Referenced by GlassDatabase::compact().

◆ is_modified()

bool GlassTable::is_modified ( ) const

inline

Determine whether the object contains uncommitted modifications.

Returns: true if there have been modifications since the last the last call to commit().

Definition at line 697 of file glass_table.h.

Referenced by GlassDatabase::apply(), GlassDatabase::compact(), GlassWritableDatabase::has_uncommitted_changes(), GlassSynonymTable::is_modified(), and GlassSpellingTable::is_modified().

◆ is_open()

bool GlassTable::is_open ( ) const

inline

Return true if this table is open.

NB If the table is lazy and doesn't yet exist, returns false.

Definition at line 506 of file glass_table.h.

Referenced by GlassWritableDatabase::add_document_(), GlassWritableDatabase::delete_document(), GlassDatabase::open_tables(), GlassDatabase::open_term_list(), GlassWritableDatabase::replace_document(), and GlassDatabase::throw_termlist_table_close_exception().

◆ is_writable()

bool GlassTable::is_writable ( ) const

inline

Return true if this table is writable.

Definition at line 509 of file glass_table.h.

References GlassFreeList::commit(), and Xapian::revision().

Referenced by GlassPostList::open_nearby_postlist().

◆ key_exists()

bool GlassTable::key_exists ( const std::string & key ) const

Check if a key exists in the Btree.

This is just like get_exact_entry() except it doesn't read the tag value so is more efficient if you only want to check that the key exists.

Parameters

key	The key to look for in the table.

Returns: true if key is found in table, false if key is not found in table.

Definition at line 1496 of file glass_table.cc.

References Assert, C, GLASS_BTREE_MAX_KEY_LEN, LOGCALL, and RETURN.

◆ mid_point()

int GlassTable::mid_point ( uint8_t * p ) const

protected

mid_point(p) finds the directory entry in c that determines the approximate mid point of the data in the block at p.

Definition at line 734 of file glass_table.cc.

References Assert, Glass::D2, Glass::DIR_END(), Glass::DIR_START, Glass::GET_LEVEL(), LOGCALL, RETURN, Glass::LeafItem_base< T >::size(), Glass::BItem_base< T >::size(), and Glass::TOTAL_FREE().

◆ next()

bool GlassTable::next	(	Glass::Cursor *	C_,
		int	j
	)		const

inlineprotected

Definition at line 860 of file glass_table.h.

References dummy.

Referenced by Glass::PostlistChunkReader::is_at_end().

◆ next_default()

bool GlassTable::next_default	(	Glass::Cursor *	C_,
		int	j
	)		const

protected

Definition at line 2163 of file glass_table.cc.

References AssertRel, block_given_by(), block_size, block_to_cursor(), Glass::Cursor::c, D2, DIR_END(), DIR_START, Glass::Cursor::get_p(), level, LOGCALL, and RETURN.

◆ next_for_sequential()

bool GlassTable::next_for_sequential	(	Glass::Cursor *	C_,
		int	dummy
	)		const

protected

Definition at line 2082 of file glass_table.cc.

References Assert, AssertRel, block_size, Glass::Cursor::c, C, Glass::Cursor::clone(), D2, DIR_END(), DIR_START, free_list, GlassFreeList::get_first_unused_block(), GET_LEVEL(), Glass::Cursor::get_n(), Glass::Cursor::get_p(), Glass::Cursor::init(), level, LOGCALL, read_block(), RETURN, REVISION(), revision_number, Glass::Cursor::set_n(), set_overwritten(), and writable.

◆ open()

void GlassTable::open	(	int	flags_,
		const RootInfo &	root_info,
		glass_revision_number_t	rev
	)

Open the btree.

Parameters

flags_	flags for opening
root_info	root block info

Exceptions

Xapian::DatabaseCorruptError	will be thrown if the table is in a corrupt state.
Xapian::DatabaseOpeningError	will be thrown if the table cannot be opened (but is not corrupt - eg, permission problems, not present, etc).

Definition at line 2010 of file glass_table.cc.

References block_size, close(), do_open_to_read(), do_open_to_write(), flags, Glass::RootInfo::get_blocksize(), Glass::RootInfo::get_root(), LOGCALL_VOID, root, and writable.

Referenced by GlassDatabase::compact(), main(), GlassDatabase::modifications_failed(), GlassPostListTable::open(), and GlassDatabase::open_tables().

◆ operator=()

GlassTable& GlassTable::operator= ( const GlassTable & )

private

Assignment not allowed.

◆ prev()

bool GlassTable::prev	(	Glass::Cursor *	C_,
		int	j
	)		const

inlineprotected

Definition at line 854 of file glass_table.h.

◆ prev_default()

bool GlassTable::prev_default	(	Glass::Cursor *	C_,
		int	j
	)		const

protected

Definition at line 2139 of file glass_table.cc.

References AssertRel, block_given_by(), block_size, block_to_cursor(), Glass::Cursor::c, D2, DIR_END(), DIR_START, Glass::Cursor::get_p(), level, LOGCALL, and RETURN.

◆ prev_for_sequential()

bool GlassTable::prev_for_sequential	(	Glass::Cursor *	C_,
		int	dummy
	)		const

protected

Definition at line 2029 of file glass_table.cc.

References AssertRel, block_size, Glass::Cursor::c, C, Glass::Cursor::clone(), D2, DIR_END(), DIR_START, GET_LEVEL(), Glass::Cursor::get_n(), Glass::Cursor::init(), level, LOGCALL, read_block(), RETURN, REVISION(), revision_number, Glass::Cursor::set_n(), set_overwritten(), and writable.

◆ read_block()

void GlassTable::read_block	(	uint4	n,
		uint8_t *	p
	)		const

protected

read_block(n, p) reads block n of the DB file to address p.

Definition at line 160 of file glass_table.cc.

References AssertRel, Glass::DIR_END(), Glass::DIR_START, Glass::GET_LEVEL(), io_read_block(), Glass::LEVEL_FREELIST, LOGCALL_VOID, rare, Xapian::Internal::str(), and throw_database_closed().

Referenced by next_for_sequential(), prev_for_sequential(), and GlassFreeList::read_block().

◆ read_root()

void GlassTable::read_root ( )

protected

Definition at line 1614 of file glass_table.cc.

References Assert, C, Glass::D2, Glass::DIR_START, Glass::LeafItem_wr::fake_root_item(), Glass::I2, Glass::K1, LOGCALL_VOID, Glass::REVISION(), Glass::SET_DIR_END(), Glass::SET_LEVEL(), Glass::SET_MAX_FREE(), Glass::SET_REVISION(), Glass::SET_TOTAL_FREE(), and Glass::LeafItem_wr::setD().

Referenced by cancel(), commit(), and do_open_to_read().

◆ read_tag()

bool GlassTable::read_tag	(	Glass::Cursor *	C_,
		std::string *	tag,
		bool	keep_compressed
	)		const

Read the tag value for the key pointed to by cursor C_.

Parameters

keep_compressed Don't uncompress the tag - e.g. useful if it's just being opaquely copied.

Returns: true if current_tag holds compressed data (always false if keep_compressed was false).

Definition at line 1509 of file glass_table.cc.

References Glass::LeafItem_base< T >::append_chunk(), Glass::LeafItem_base< T >::decompress_chunk(), Glass::LeafItem_base< T >::get_compressed(), Glass::LeafItem_base< T >::last_component(), LOGCALL, and RETURN.

◆ readahead_key()

bool GlassTable::readahead_key ( const string & key ) const

Definition at line 1430 of file glass_table.cc.

References Assert, Glass::BItem_base< T >::block_given_by(), C, GLASS_BTREE_MAX_KEY_LEN, io_readahead_block(), LOGCALL, and RETURN.

Referenced by GlassDocDataTable::readahead_for_document(), and GlassDatabase::readahead_for_query().

◆ set_changes()

void GlassTable::set_changes ( GlassChanges * changes )

inline

Set the GlassChanges object to write changed blocks to.

The GlassChanges object is not owned by the table, so the table must not delete it.

Definition at line 721 of file glass_table.h.

References throw_database_closed().

Referenced by GlassDatabase::apply(), GlassDatabase::modifications_failed(), and GlassDatabase::open_tables().

◆ set_full_compaction()

void GlassTable::set_full_compaction ( bool parity )

Definition at line 1553 of file glass_table.cc.

References Assert, and LOGCALL_VOID.

Referenced by GlassDatabase::compact().

◆ set_max_item_size()

void GlassTable::set_max_item_size ( size_t block_capacity )

inline

Set the maximum item size given the block capacity.

At least this many items of maximum size must fit into a block. The default is BLOCK_CAPACITY (which is currently 4).

Definition at line 704 of file glass_table.h.

References Glass::BLOCK_CAPACITY, Glass::D2, Glass::DIR_START, and Glass::MAX_ITEM_SIZE.

Referenced by GlassDatabase::compact().

◆ set_overwritten()

void GlassTable::set_overwritten ( ) const

protected

Definition at line 289 of file glass_table.cc.

References LOGCALL_VOID.

Referenced by next_for_sequential(), and prev_for_sequential().

◆ single_file()

bool GlassTable::single_file ( ) const

inlineprotected

Definition at line 849 of file glass_table.h.

Referenced by close(), do_open_to_read(), and exists().

◆ split_root()

void GlassTable::split_root ( uint4 split_n )

protected

Btree needs to gain a new level to insert more items: so split root block and construct a new one.

Definition at line 600 of file glass_table.cc.

References C, Glass::DIR_START, Glass::BItem_wr::form_null_key(), GLASS_BTREE_CURSOR_LEVELS, LOGCALL_VOID, Glass::SET_DIR_END(), Glass::SET_LEVEL(), Glass::SET_REVISION(), and STRINGIZE.

◆ sync()

bool GlassTable::sync ( )

inline

Definition at line 535 of file glass_table.h.

References Xapian::DB_NO_SYNC, and io_sync().

Referenced by GlassDatabase::compact(), and GlassDatabase::set_revision_number().

◆ throw_database_closed()

void GlassTable::throw_database_closed ( )

static

Throw an exception indicating that the database is closed.

Definition at line 2195 of file glass_table.cc.

Referenced by add(), cancel(), commit(), create_and_open(), cursor_get(), del(), do_open_to_read(), do_open_to_write(), flush_db(), GlassValueManager::get_all_values(), get_exact_entry(), GlassDatabase::open_tables(), read_block(), and GlassDatabase::throw_termlist_table_close_exception().

◆ write_block()

void GlassTable::write_block	(	uint4	n,
		const uint8_t *	p,
		bool	appending = `false`
	)		const

protected

write_block(n, p, appending) writes block n in the DB file from address p.

If appending is true (not specified it defaults to false), then this indicates that we've added data to a block in space which was previously unused, and are writing the block back in place - we use this to add free list entries (the information about where the freelist data for a revision begins and ends is stored in the "iamglass" file). We don't currently use this flag for much, but it signifies that we don't risk invalidating any existing revisions, which may be useful information.

Definition at line 191 of file glass_table.cc.

References Assert, AssertEqParanoid, AssertRel, Xapian::DB_DANGEROUS, Glass::DOCDATA, io_write_block(), LOGCALL_VOID, pack_uint(), Glass::POSITION, Glass::POSTLIST, Glass::REVISION(), Glass::SPELLING, Glass::SYNONYM, and Glass::TERMLIST.

Referenced by flush_db(), and GlassFreeList::write_block().

Friends And Related Function Documentation

◆ GlassCursor

friend class GlassCursor

friend

Definition at line 426 of file glass_table.h.

◆ GlassFreeList

friend class GlassFreeList

friend

Definition at line 427 of file glass_table.h.

Member Data Documentation

◆ block_size

unsigned int GlassTable::block_size

protected

block size of the B tree in bytes

Definition at line 767 of file glass_table.h.

Referenced by cancel(), commit(), create_and_open(), next_default(), next_for_sequential(), open(), prev_default(), and prev_for_sequential().

◆ Btree_modified

bool GlassTable::Btree_modified

mutableprotected

Set to true the first time the B-tree is modified.

Definition at line 829 of file glass_table.h.

Referenced by cancel(), and commit().

◆ buffer

uint8_t* GlassTable::buffer

protected

buffer of size block_size for reforming blocks

Definition at line 802 of file glass_table.h.

Referenced by close().

◆ C

Glass::Cursor GlassTable::C[GLASS_BTREE_CURSOR_LEVELS]

mutableprotected

Definition at line 884 of file glass_table.h.

Referenced by cancel(), close(), commit(), flush_db(), next_for_sequential(), and prev_for_sequential().

◆ changed_c

int GlassTable::changed_c

protected

directory offset corresponding to last block to be changed by an addition

Definition at line 823 of file glass_table.h.

Referenced by cancel(), and commit().

◆ changed_n

uint4 GlassTable::changed_n

protected

the last block to be changed by an addition

Definition at line 819 of file glass_table.h.

Referenced by cancel(), and commit().

◆ changes_obj

GlassChanges* GlassTable::changes_obj

protected

The GlassChanges object to write block changes to.

If NULL, no changes will be written.

Definition at line 847 of file glass_table.h.

◆ comp_stream

CompressionStream GlassTable::comp_stream

mutableprotected

Definition at line 896 of file glass_table.h.

◆ compress_min

uint4 GlassTable::compress_min

protected

Minimum size tag to try compressing (0 for no compression).

Definition at line 894 of file glass_table.h.

Referenced by create_and_open().

◆ cursor_created_since_last_modification

bool GlassTable::cursor_created_since_last_modification

mutableprotected

Flag for tracking when cursors need to rebuild.

Definition at line 838 of file glass_table.h.

Referenced by cancel().

◆ cursor_version

unsigned long GlassTable::cursor_version

protected

Version count for tracking when cursors need to rebuild.

Definition at line 841 of file glass_table.h.

Referenced by cancel().

◆ faked_root_block

bool GlassTable::faked_root_block

protected

true if the root block is faked (not written to disk).

false otherwise. This is true when the btree hasn't been modified yet.

Definition at line 776 of file glass_table.h.

Referenced by cancel(), commit(), and flush_db().

◆ flags

int GlassTable::flags

protected

Flags like DB_NO_SYNC and DB_DANGEROUS.

Definition at line 770 of file glass_table.h.

Referenced by cancel(), create_and_open(), and open().

◆ free_list

GlassFreeList GlassTable::free_list

protected

List of free blocks.

Definition at line 805 of file glass_table.h.

Referenced by cancel(), commit(), and next_for_sequential().

◆ full_compaction

bool GlassTable::full_compaction

protected

set to true when full compaction is to be achieved

Definition at line 832 of file glass_table.h.

◆ handle

int GlassTable::handle

protected

File descriptor of the table.

If close() has been called, this will be -2.

If the table is lazily created and doesn't yet exist, this will be -1 (for a multi-file database) or -3-fd (for a single-file database).

Definition at line 790 of file glass_table.h.

Referenced by cancel(), close(), commit(), create_and_open(), do_open_to_read(), and flush_db().

◆ item_count

glass_tablesize_t GlassTable::item_count

protected

keeps a count of the number of items in the B-tree.

Definition at line 764 of file glass_table.h.

Referenced by cancel(), and commit().

◆ kt

Glass::LeafItem_wr GlassTable::kt

mutableprotected

buffer of size block_size for making up key-tag items

Definition at line 799 of file glass_table.h.

Referenced by close().

◆ last_readahead

uint4 GlassTable::last_readahead

mutableprotected

Last block readahead_key() preread.

Definition at line 902 of file glass_table.h.

◆ lazy

bool GlassTable::lazy

protected

If true, don't create the table until it's needed.

Definition at line 899 of file glass_table.h.

Referenced by create_and_open(), and do_open_to_read().

◆ level

int GlassTable::level

protected

number of levels, counting from 0

Definition at line 793 of file glass_table.h.

Referenced by cancel(), close(), commit(), flush_db(), next_default(), next_for_sequential(), prev_default(), and prev_for_sequential().

◆ max_item_size

size_t GlassTable::max_item_size

protected

maximum size of an item (key-tag pair)

Definition at line 826 of file glass_table.h.

◆ name

std::string GlassTable::name

protected

The path name of the B tree.

For a single-file database, this will be empty.

Definition at line 811 of file glass_table.h.

Referenced by do_open_to_read().

◆ offset

off_t GlassTable::offset

protected

offset to start of table in file.

Definition at line 905 of file glass_table.h.

◆ revision_number

glass_revision_number_t GlassTable::revision_number

protected

revision number of the opened B-tree.

Definition at line 761 of file glass_table.h.

Referenced by cancel(), commit(), do_open_to_read(), next_for_sequential(), and prev_for_sequential().

◆ root

uint4 GlassTable::root

protected

the root block of the B-tree

Definition at line 796 of file glass_table.h.

Referenced by cancel(), commit(), and open().

◆ seq_count

int GlassTable::seq_count

protected

count of the number of successive instances of purely sequential addition, starting at SEQ_START_POINT (neg) and going up to zero.

Definition at line 816 of file glass_table.h.

Referenced by cancel(), and commit().

◆ sequential

bool GlassTable::sequential

protected

true iff the data has been written in a single write in sequential order.

Definition at line 781 of file glass_table.h.

Referenced by cancel(), and commit().

◆ split_p

uint8_t* GlassTable::split_p

protected

Buffer used when splitting a block.

This buffer holds the split off part of the block. It's only used when updating (in GlassTable::add_item().

Definition at line 891 of file glass_table.h.

Referenced by close().

◆ tablename

const char* GlassTable::tablename

protected

The name of the table (used when writing changesets).

Definition at line 758 of file glass_table.h.

◆ writable

bool GlassTable::writable

protected

Set to true when the database is opened to write.

Definition at line 835 of file glass_table.h.

Referenced by cancel(), commit(), create_and_open(), flush_db(), next_for_sequential(), open(), and prev_for_sequential().

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

backends/glass/glass_table.h
backends/glass/glass_table.cc

Public Member Functions

Static Public Member Functions

Protected Member Functions

Static Protected Member Functions

Protected Attributes

Private Member Functions

Friends

Detailed Description

Constructor & Destructor Documentation

◆ GlassTable() [1/3]

◆ GlassTable() [2/3]

◆ GlassTable() [3/3]

◆ ~GlassTable()

Member Function Documentation

◆ add()

◆ add_branch_item()

◆ add_item_to_branch()

◆ add_item_to_leaf()

◆ add_kt()

◆ add_leaf_item()

◆ alter()

◆ basic_open()

◆ block_given_by()

◆ block_to_cursor()

◆ cancel()

◆ close()

◆ commit()

◆ compact()

◆ create_and_open()

◆ cursor_get()

◆ del()

◆ delete_branch_item()

◆ delete_kt()

◆ delete_leaf_item()

◆ do_open_to_read()

◆ do_open_to_write()

◆ empty()

◆ enter_key_above_branch()

◆ enter_key_above_leaf()

◆ exists()

◆ find()

◆ find_in_branch() [1/2]

◆ find_in_branch() [2/2]

◆ find_in_leaf()

◆ flush_db()

◆ form_key()

◆ get_entry_count()

◆ get_exact_entry()

◆ get_flags()

◆ get_open_revision_number()

◆ get_path()

◆ is_modified()

◆ is_open()

◆ is_writable()

◆ key_exists()

◆ mid_point()

◆ next()

◆ next_default()

◆ next_for_sequential()

◆ open()

◆ operator=()

◆ prev()

◆ prev_default()

◆ prev_for_sequential()

◆ read_block()

◆ read_root()

◆ read_tag()

◆ readahead_key()

◆ set_changes()

◆ set_full_compaction()

◆ set_max_item_size()

◆ set_overwritten()

◆ single_file()

◆ split_root()

◆ sync()

◆ throw_database_closed()

◆ write_block()

Friends And Related Function Documentation

◆ GlassCursor

◆ GlassFreeList