#include "univ.i"
#include "data0data.h"
#include "dict0types.h"
#include "trx0types.h"
#include "que0types.h"
#include "rem0types.h"
#include "mtr0mtr.h"
#include "read0types.h"
#include "row0vers.ic"

Include dependency graph for row0vers.h:

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Functions
UNIV_INTERN trx_id_t	row_vers_impl_x_locked (const rec_t rec, dict_index_t index, const ulint *offsets)
UNIV_INTERN ibool	row_vers_must_preserve_del_marked (trx_id_t trx_id, mtr_t *mtr)
UNIV_INTERN ibool	row_vers_old_has_index_entry (ibool also_curr, const rec_t rec, mtr_t mtr, dict_index_t index, const dtuple_t ientry)
UNIV_INTERN dberr_t	row_vers_build_for_consistent_read (const rec_t rec, mtr_t mtr, dict_index_t index, ulint offsets, read_view_t view, mem_heap_t *offset_heap, mem_heap_t in_heap, rec_t **old_vers)))
UNIV_INTERN void	row_vers_build_for_semi_consistent_read (const rec_t rec, mtr_t mtr, dict_index_t index, ulint offsets, mem_heap_t offset_heap, mem_heap_t in_heap, const rec_t **old_vers)))

Detailed Description

Row versions

Created 2/6/1997 Heikki Tuuri

Function Documentation

UNIV_INTERN dberr_t row_vers_build_for_consistent_read	(	const rec_t *	rec,
		mtr_t *	mtr,
		dict_index_t *	index,
		ulint **	offsets,
		read_view_t *	view,
		mem_heap_t **	offset_heap,
		mem_heap_t *	in_heap,
		rec_t **	old_vers
	)

Constructs the version of a clustered index record which a consistent read should see. We assume that the trx id stored in rec is such that the consistent read should not see rec in its present version.

Returns: DB_SUCCESS or DB_MISSING_HISTORY

Parameters

rec	in: record in a clustered index; the caller must have a latch on the page; this latch locks the top of the stack of versions of this records
mtr	in: mtr holding the latch on rec; it will also hold the latch on purge_view
index	in: the clustered index
offsets	in/out: offsets returned by rec_get_offsets(rec, index)
view	in: the consistent read view
offset_heap	in/out: memory heap from which the offsets are allocated
in_heap	in: memory heap from which the memory for *old_vers is allocated; memory for possible intermediate versions is allocated and freed locally within the function
old_vers	out, own: old version, or NULL if the history is missing or the record does not exist in the view, that is, it was freshly inserted afterwards

UNIV_INTERN void row_vers_build_for_semi_consistent_read	(	const rec_t *	rec,
		mtr_t *	mtr,
		dict_index_t *	index,
		ulint **	offsets,
		mem_heap_t **	offset_heap,
		mem_heap_t *	in_heap,
		const rec_t **	old_vers
	)

Constructs the last committed version of a clustered index record, which should be seen by a semi-consistent read.

Parameters

rec	in: record in a clustered index; the caller must have a latch on the page; this latch locks the top of the stack of versions of this records
mtr	in: mtr holding the latch on rec
index	in: the clustered index
offsets	in/out: offsets returned by rec_get_offsets(rec, index)
offset_heap	in/out: memory heap from which the offsets are allocated
in_heap	in: memory heap from which the memory for *old_vers is allocated; memory for possible intermediate versions is allocated and freed locally within the function
old_vers	out: rec, old version, or NULL if the record does not exist in the view, that is, it was freshly inserted afterwards

UNIV_INTERN trx_id_t row_vers_impl_x_locked	(	const rec_t *	rec,
		dict_index_t *	index,
		const ulint *	offsets
	)

Finds out if an active transaction has inserted or modified a secondary index record.

Returns: 0 if committed, else the active transaction id; NOTE that this function can return false positives but never false negatives. The caller must confirm all positive results by calling trx_is_active() while holding lock_sys->mutex. in: rec_get_offsets(rec, index)

Parameters

rec	in: record in a secondary index
index	in: the secondary index

UNIV_INTERN ibool row_vers_must_preserve_del_marked	(	trx_id_t	trx_id,
		mtr_t *	mtr
	)

Finds out if we must preserve a delete marked earlier version of a clustered index record, because it is >= the purge view.

Returns: TRUE if earlier version should be preserved in: mtr holding the latch on the clustered index record; it will also hold the latch on purge_view

Parameters

trx_id in: transaction id in the version

UNIV_INTERN ibool row_vers_old_has_index_entry	(	ibool	also_curr,
		const rec_t *	rec,
		mtr_t *	mtr,
		dict_index_t *	index,
		const dtuple_t *	ientry
	)

Finds out if a version of the record, where the version >= the current purge view, should have ientry as its secondary index entry. We check if there is any not delete marked version of the record where the trx id >= purge view, and the secondary index entry == ientry; exactly in this case we return TRUE.

Returns: TRUE if earlier version should have in: the secondary index entry

Parameters

also_curr	in: TRUE if also rec is included in the versions to search; otherwise only versions prior to it are searched
rec	in: record in the clustered index; the caller must have a latch on the page
mtr	in: mtr holding the latch on rec; it will also hold the latch on purge_view
index	in: the secondary index

Functions

Detailed Description

Function Documentation