The transaction lock system. More...

#include "buf0types.h"
#include "dict0types.h"
#include "hash0hash.h"
#include "lock0types.h"
#include "mtr0types.h"
#include "que0types.h"
#include "rem0types.h"
#include "srv0srv.h"
#include "trx0types.h"
#include "univ.i"
#include "ut0vec.h"
#include "gis0rtree.h"
#include "lock0latches.h"
#include "lock0prdt.h"
#include "ut0sharded_bitset.h"
#include "lock0lock.ic"
#include "lock0guards.h"

Classes
class	locksys::Trx_locks_cache
	An object which can be passed to consecutive calls to rec_lock_has_to_wait(trx, mode, lock, is_supremum, trx_locks_cache) for the same trx and heap_no (which is implicitly the bit common to all lock objects passed) which can be used by this function to cache some partial results. More...

struct	lock_op_t
	Lock operation struct. More...

struct	Locks_hashtable
	A hashmap used by lock sys, to organize locks by page (block), so that it is easy to maintain a list of all locks related to a given page by append(lock,..), prepend(lock,..), erase(lock,..), move_to_front(lock,...) while also providing ability to iterate over all locks related for a given page in that order. More...

struct	lock_sys_t
	The lock system struct. More...

Namespaces
namespace	locksys

Typedefs
typedef ib_mutex_t	Lock_mutex

Enumerations
enum class	lock_duration_t { REGULAR = 0 , AT_LEAST_STATEMENT = 1 }
	Used to specify the intended duration of a record lock. More...

Functions
ulint	lock_get_size (void)
	Gets the size of a lock struct. More...

void	lock_sys_create (ulint n_cells)
	Creates the lock system at database start. More...

void	lock_sys_resize (ulint n_cells)
	Resize the lock hash tables. More...

void	lock_sys_close (void)
	Closes the lock system at database shutdown. More...

static ulint	lock_get_min_heap_no (const buf_block_t *block)
	Gets the heap_no of the smallest user record on a page. More...

void	lock_move_reorganize_page (const buf_block_t block, const buf_block_t oblock)
	Updates the lock table when we have reorganized a page. More...

void	lock_move_rec_list_end (const buf_block_t new_block, const buf_block_t block, const rec_t *rec)
	Moves the explicit locks on user records to another page if a record list end is moved to another page. More...

void	lock_move_rec_list_start (const buf_block_t new_block, const buf_block_t block, const rec_t rec, const rec_t old_end)
	Moves the explicit locks on user records to another page if a record list start is moved to another page. More...

void	lock_update_split_right (const buf_block_t right_block, const buf_block_t left_block)
	Updates the lock table when a page is split to the right. More...

void	lock_update_merge_right (const buf_block_t right_block, const rec_t orig_succ, const buf_block_t *left_block)
	Updates the lock table when a page is merged to the right. More...

void	lock_update_root_raise (const buf_block_t block, const buf_block_t root)
	Updates the lock table when the root page is copied to another in btr_root_raise_and_insert. More...

void	lock_update_copy_and_discard (const buf_block_t new_block, const buf_block_t block)
	Updates the lock table when a page is copied to another and the original page is removed from the chain of leaf pages, except if page is the root! More...

void	lock_update_split_point (const buf_block_t right_block, const buf_block_t left_block)
	Requests the Lock System to update record locks regarding the gap between the last record of the left_page and the first record of the right_page when the caller is about to prepended a new record as the first record on the right page, even though it should "naturally" be inserted as the last record of the left_page according to the information in the higher levels of the index. More...

void	lock_update_split_left (const buf_block_t right_block, const buf_block_t left_block)
	Updates the lock table when a page is split to the left. More...

void	lock_update_merge_left (const buf_block_t left_block, const rec_t orig_pred, const buf_block_t *right_block)
	Updates the lock table when a page is merged to the left. More...

void	lock_rec_reset_and_inherit_gap_locks (const buf_block_t heir_block, const buf_block_t block, ulint heir_heap_no, ulint heap_no)
	Resets the original locks on heir and replaces them with gap type locks inherited from rec. More...

void	lock_update_discard (const buf_block_t heir_block, ulint heir_heap_no, const buf_block_t block)
	Updates the lock table when a page is discarded. More...

void	lock_update_insert (const buf_block_t block, const rec_t rec)
	Updates the lock table when a new user record is inserted. More...

void	lock_update_delete (const buf_block_t block, const rec_t rec)
	Updates the lock table when a record is removed. More...

void	lock_rec_store_on_page_infimum (const buf_block_t block, const rec_t rec)
	Stores on the page infimum record the explicit locks of another record. More...

void	lock_rec_restore_from_page_infimum (const buf_block_t block, const rec_t rec, const buf_block_t *donator)
	Restores the state of explicit lock requests on a single record, where the state was stored on the infimum of the page. More...

bool	lock_rec_expl_exist_on_page (const page_id_t &page_id)
	Determines if there are explicit record locks on a page. More...

dberr_t	lock_rec_insert_check_and_lock (ulint flags, const rec_t rec, buf_block_t block, dict_index_t index, que_thr_t thr, mtr_t mtr, bool inherit)
	Checks if locks of other transactions prevent an immediate insert of a record. More...

dberr_t	lock_clust_rec_modify_check_and_lock (ulint flags, const buf_block_t block, const rec_t rec, dict_index_t index, const ulint offsets, que_thr_t *thr)
	Checks if locks of other transactions prevent an immediate modify (update, delete mark, or delete unmark) of a clustered index record. More...

dberr_t	lock_sec_rec_modify_check_and_lock (ulint flags, buf_block_t block, const rec_t rec, dict_index_t index, que_thr_t thr, mtr_t *mtr)
	Checks if locks of other transactions prevent an immediate modify (delete mark or delete unmark) of a secondary index record. More...

void	lock_on_statement_end (trx_t *trx)
	Called to inform lock-sys that a statement processing for a trx has just finished. More...

dberr_t	lock_sec_rec_read_check_and_lock (lock_duration_t duration, const buf_block_t block, const rec_t rec, dict_index_t index, const ulint offsets, select_mode sel_mode, lock_mode mode, ulint gap_mode, que_thr_t *thr)
	Like lock_clust_rec_read_check_and_lock(), but reads a secondary index record. More...

dberr_t	lock_clust_rec_read_check_and_lock (lock_duration_t duration, const buf_block_t block, const rec_t rec, dict_index_t index, const ulint offsets, select_mode sel_mode, lock_mode mode, ulint gap_mode, que_thr_t *thr)
	Checks if locks of other transactions prevent an immediate read, or passing over by a read cursor, of a clustered index record. More...

dberr_t	lock_clust_rec_read_check_and_lock_alt (const buf_block_t block, const rec_t rec, dict_index_t index, lock_mode mode, ulint gap_mode, que_thr_t thr)
	Checks if locks of other transactions prevent an immediate read, or passing over by a read cursor, of a clustered index record. More...

bool	lock_clust_rec_cons_read_sees (const rec_t rec, dict_index_t index, const ulint offsets, ReadView view)
	Checks that a record is seen in a consistent read. More...

bool	lock_sec_rec_cons_read_sees (const rec_t rec, const dict_index_t index, const ReadView *view)
	Checks that a non-clustered index record is seen in a consistent read. More...

dberr_t	lock_table (ulint flags, dict_table_t table, lock_mode mode, que_thr_t thr)
	Locks the specified database table in the mode given. More...

void	lock_table_ix_resurrect (dict_table_t table, trx_t trx)
	Creates a table IX lock object for a resurrected transaction. More...

dberr_t	lock_table_for_trx (dict_table_t table, trx_t trx, enum lock_mode mode)
	Sets a lock on a table based on the given mode. More...

void	lock_rec_unlock (trx_t trx, const buf_block_t block, const rec_t *rec, lock_mode lock_mode)
	Removes a granted record lock of a transaction from the queue and grants locks to other transactions waiting in the queue if they now are entitled to a lock. More...

void	lock_trx_release_locks (trx_t *trx)
	Releases a transaction's locks, and releases possible other transactions waiting because of these locks. More...

void	lock_trx_release_read_locks (trx_t *trx, bool only_gap)
	Release read locks of a transaction. More...

void	lock_make_trx_hit_list (trx_t *trx, hit_list_t &hit_list)
	Iterate over the granted locks which conflict with trx->lock.wait_lock and prepare the hit list for ASYNC Rollback. More...

void	lock_remove_all_on_table (dict_table_t *table, bool remove_also_table_sx_locks)
	Removes locks on a table to be dropped. More...

static uint64_t	lock_rec_hash_value (const page_id_t &page_id)
	Calculates the hash value of a page file address: used in inserting or searching for a lock in the hash table or getting global shard index. More...

ulint	lock_rec_find_set_bit (const lock_t *lock)
	Looks for a set bit in a record lock bitmap. More...

ulint	lock_rec_find_next_set_bit (const lock_t *lock, ulint heap_no)
	Looks for the next set bit in the record lock bitmap. More...

bool	lock_has_to_wait (const lock_t lock1, const lock_t lock2)
	Checks if a lock request lock1 has to wait for request lock2. More...

bool	locksys::has_to_wait (const lock_t lock1, const lock_t lock2, Trx_locks_cache &lock1_cache)
	Checks if a lock request lock1 has to wait for request lock2. More...

void	lock_report_trx_id_insanity (trx_id_t trx_id, const rec_t rec, const dict_index_t index, const ulint *offsets, trx_id_t next_trx_id)
	Reports that a transaction id is insensible, i.e., in the future. More...

void	lock_print_info_summary (FILE *file)
	Prints info of locks for all transactions. More...

void	lock_trx_print_wait_and_mvcc_state (FILE file, const trx_t trx)
	Prints transaction lock wait and MVCC state. More...

void	lock_print_info_all_transactions (FILE *file)
	Prints info of locks for each transaction. More...

ulint	lock_number_of_rows_locked (const trx_lock_t *trx_lock)
	Return approximate number or record locks (bits set in the bitmap) for this transaction. More...

ulint	lock_number_of_tables_locked (const trx_t *trx)
	Return the number of table locks for a transaction. More...

uint32_t	lock_get_type (const lock_t *lock)
	Gets the type of a lock. More...

trx_id_t	lock_get_trx_id (const lock_t *lock)
	Gets the id of the transaction owning a lock. More...

void	lock_get_psi_event (const lock_t lock, ulonglong thread_id, ulonglong *event_id)
	Get the performance schema event (thread_id, event_id) that created the lock. More...

const char *	lock_get_mode_str (const lock_t *lock)
	Gets the mode of a lock in a human readable string. More...

const char *	lock_get_type_str (const lock_t *lock)
	Gets the type of a lock in a human readable string. More...

table_id_t	lock_get_table_id (const lock_t *lock)
	Gets the id of the table on which the lock is. More...

const table_name_t &	lock_get_table_name (const lock_t *lock)
	Determine which table a lock is associated with. More...

const dict_index_t *	lock_rec_get_index (const lock_t *lock)
	For a record lock, gets the index on which the lock is. More...

const char *	lock_rec_get_index_name (const lock_t *lock)
	For a record lock, gets the name of the index on which the lock is. More...

page_id_t	lock_rec_get_page_id (const lock_t *lock)
	For a record lock, gets the tablespace number and page number on which the lock is. More...

bool	lock_table_has_locks (const dict_table_t *table)
	Check if there are any locks (table or rec) against table. More...

void	lock_wait_timeout_thread ()
	A thread which wakes up threads whose lock wait may have lasted too long. More...

void	lock_wait_request_check_for_cycles ()
	Notifies the thread which analyzes wait-for-graph that there was at least one new edge added or modified ( trx->blocking_trx has changed ), so that the thread will know it has to analyze it. More...

void	lock_wait_suspend_thread (que_thr_t *thr)
	Puts a user OS thread to wait for a lock to be released. More...

void	lock_unlock_table_autoinc (trx_t *trx)
	Unlocks AUTO_INC type locks that were possibly reserved by a trx. More...

bool	lock_cancel_if_waiting_and_release (TrxVersion trx_version)
	Cancels the waiting lock request of the trx, if any. More...

void	lock_set_timeout_event ()
	Set the lock system timeout event. More...

bool	lock_check_trx_id_sanity (trx_id_t trx_id, const rec_t rec, const dict_index_t index, const ulint *offsets)
	Checks that a transaction id is sensible, i.e., not in the future. More...

bool	lock_trx_has_rec_x_lock (que_thr_t thr, const dict_table_t table, const buf_block_t *block, ulint heap_no)
	Check if the transaction holds an exclusive lock on a record. More...

bool	lock_validate ()
	Validates the lock system. More...

void	lock_trx_alloc_locks (trx_t *trx)
	Allocate cached locks for the transaction. More...

void	lock_rec_convert_impl_to_expl (const buf_block_t block, const rec_t rec, dict_index_t index, const ulint offsets)
	If a transaction has an implicit x-lock on a record, but no explicit x-lock set on the record, sets one for it. More...

void	lock_rec_discard (lock_t *in_lock)
	Removes a record lock request, waiting or granted, from the queue. More...

void	lock_rtr_move_rec_list (const buf_block_t new_block, const buf_block_t block, rtr_rec_move_t *rec_move, ulint num_move)
	Moves the explicit locks on user records to another page if a record list start is moved to another page. More...

void	lock_rec_free_all_from_discard_page (const buf_block_t *block)
	Removes record lock objects set on an index page which is discarded. More...

bool	lock_rec_clear_request_no_wakeup (lock_t *lock, uint16_t heap_no)
	Reset the nth bit of a record lock. More...

bool	lock_is_waiting (const lock_t &lock)
	Checks if the lock is waiting (as opposed to granted). More...

const lock_t *	lock_find_table_lock_by_guid (const dict_table_t *table, const lock_guid_t &guid)
	Inspect the lock queue associated with the given table in search for a lock which has guid equal to the given one. More...

const lock_t *	lock_find_record_lock_by_guid (page_id_t page_id, const lock_guid_t &guid)
	Inspect the lock queues associated with the given page_id in search for a lock which has guid equal to the given one. More...

static bool	lock_wait_mutex_own ()
	Test if lock_sys->wait_mutex is owned. More...

static void	lock_wait_mutex_enter ()
	Acquire the lock_sys->wait_mutex. More...

static void	lock_wait_mutex_exit ()
	Release the lock_sys->wait_mutex. More...

bool	locksys::owns_exclusive_global_latch ()
	Tests if lock_sys latch is exclusively owned by the current thread. More...

bool	locksys::owns_shared_global_latch ()
	Tests if lock_sys latch is owned in shared mode by the current thread. More...

bool	locksys::owns_page_shard (const page_id_t &page_id)
	Tests if given page shard can be safely accessed by the current thread. More...

bool	locksys::owns_table_shard (const dict_table_t &table)
	Test if given table shard can be safely accessed by the current thread. More...

bool	locksys::owns_lock_shard (const lock_t *lock)
	Checks if shard which contains lock is latched (or that an exclusive latch on whole lock_sys is held) by current thread. More...

Variables
bool	innobase_deadlock_detect

lock_sys_t *	lock_sys
	The lock system. More...


constexpr uint32_t	LOCK_MODE_MASK = 0xF
	Lock modes and types. More...

constexpr uint32_t	LOCK_TABLE = 16
	Lock types. More...

constexpr uint32_t	LOCK_REC = 32
	record lock More...

constexpr uint32_t	LOCK_TYPE_MASK = 0xF0UL
	mask used to extract lock type from the type_mode field in a lock More...

constexpr uint32_t	LOCK_WAIT = 256
	Waiting lock flag; when set, it means that the lock has not yet been granted, it is just waiting for its turn in the wait queue. More...

constexpr uint32_t	LOCK_ORDINARY = 0
	this flag denotes an ordinary next-key lock in contrast to LOCK_GAP or LOCK_REC_NOT_GAP More...

constexpr uint32_t	LOCK_GAP = 512
	when this bit is set, it means that the lock holds only on the gap before the record; for instance, an x-lock on the gap does not give permission to modify the record on which the bit is set; locks of this type are created when records are removed from the index chain of records More...

constexpr uint32_t	LOCK_REC_NOT_GAP = 1024
	this bit means that the lock is only on the index record and does NOT block inserts to the gap before the index record; this is used in the case when we retrieve a record with a unique key, and is also used in locking plain SELECTs (not part of UPDATE or DELETE) when the user has set the READ COMMITTED isolation level More...

constexpr uint32_t	LOCK_INSERT_INTENTION = 2048
	this bit is set when we place a waiting gap type record lock request in order to let an insert of an index record to wait until there are no conflicting locks by other transactions on the gap; note that this flag remains set when the waiting lock is granted, or if the lock is inherited to a neighboring record More...

constexpr uint32_t	LOCK_PREDICATE = 8192
	Predicate lock. More...

constexpr uint32_t	LOCK_PRDT_PAGE = 16384
	Page lock. More...

Detailed Description

The transaction lock system.

Created 5/7/1996 Heikki Tuuri

Typedef Documentation

◆ Lock_mutex

typedef ib_mutex_t Lock_mutex

Enumeration Type Documentation

◆ lock_duration_t

enum class lock_duration_t

strong

Used to specify the intended duration of a record lock.

Enumerator
REGULAR	Keep the lock according to the rules of particular isolation level, in particular in case of READ COMMITTED or less restricive modes, do not inherit the lock if the record is purged.
AT_LEAST_STATEMENT	Keep the lock around for at least the duration of the current statement, in particular make sure it is inherited as gap lock if the record is purged.

Function Documentation

◆ lock_cancel_if_waiting_and_release()

bool lock_cancel_if_waiting_and_release ( TrxVersion trx_version )

Cancels the waiting lock request of the trx, if any.

If the transaction has already committed (trx->version has changed) or is no longer waiting for a lock (trx->lock.blocking_trx is nullptr) this function will not cancel the waiting lock.

Note

There is a possibility of ABA in which a waiting lock request was already granted or canceled and then the trx requested another lock and started waiting for it - in such case this function might either cancel or not the second request depending on timing. Currently all usages of this function ensure that this is impossible:

innodb_kill_connection ensures trx_is_interrupted(trx), thus upon first wake up it will realize it has to report an error and rollback
HP transaction marks the trx->in_innodb & TRX_FORCE_ROLLBACK flag which is checked when the trx attempts RecLock::add_to_waitq and reports DB_DEADLOCK

Parameters

[in] trx_version The trx we want to wake up and its expected version

Returns: true iff the function did release a waiting lock

◆ lock_check_trx_id_sanity()

bool lock_check_trx_id_sanity	(	trx_id_t	trx_id,
		const rec_t *	rec,
		const dict_index_t *	index,
		const ulint *	offsets
	)

Checks that a transaction id is sensible, i.e., not in the future.

Emits an error otherwise.

Parameters

[in]	trx_id	The trx id to check, found in user record or secondary index page header
[in]	rec	The user record which contained the trx_id in its header or in header of its page
[in]	index	The index which contained the rec
[in]	offsets	The result of rec_get_offsets(rec, index)

Returns: true iff ok

◆ lock_clust_rec_cons_read_sees()

bool lock_clust_rec_cons_read_sees	(	const rec_t *	rec,
		dict_index_t *	index,
		const ulint *	offsets,
		ReadView *	view
	)

Checks that a record is seen in a consistent read.

Returns: true if sees, or false if an earlier version of the record should be retrieved in: consistent read view; true if sees, or false if an earlier version of the record should be retrieved

Parameters

rec	in: user record which should be read or passed over by a read cursor
index	in: clustered index
offsets	in: rec_get_offsets(rec, index)
view	in: consistent read view

◆ lock_clust_rec_modify_check_and_lock()

dberr_t lock_clust_rec_modify_check_and_lock	(	ulint	flags,
		const buf_block_t *	block,
		const rec_t *	rec,
		dict_index_t *	index,
		const ulint *	offsets,
		que_thr_t *	thr
	)

Checks if locks of other transactions prevent an immediate modify (update, delete mark, or delete unmark) of a clustered index record.

If they do, first tests if the query thread should anyway be suspended for some reason; if not, then puts the transaction and the query thread to the lock wait state and inserts a waiting request for a record x-lock to the lock queue.

Returns: DB_SUCCESS, DB_LOCK_WAIT, or DB_DEADLOCK in: query thread

If they do, first tests if the query thread should anyway be suspended for some reason; if not, then puts the transaction and the query thread to the lock wait state and inserts a waiting request for a record x-lock to the lock queue.

Returns: DB_SUCCESS, DB_LOCK_WAIT, or DB_DEADLOCK

Parameters

flags	in: if BTR_NO_LOCKING_FLAG bit is set, does nothing
block	in: buffer block of rec
rec	in: record which should be modified
index	in: clustered index
offsets	in: rec_get_offsets(rec, index)
thr	in: query thread

◆ lock_clust_rec_read_check_and_lock()

dberr_t lock_clust_rec_read_check_and_lock	(	lock_duration_t	duration,
		const buf_block_t *	block,
		const rec_t *	rec,
		dict_index_t *	index,
		const ulint *	offsets,
		select_mode	sel_mode,
		lock_mode	mode,
		ulint	gap_mode,
		que_thr_t *	thr
	)

Checks if locks of other transactions prevent an immediate read, or passing over by a read cursor, of a clustered index record.

If they do, first tests if the query thread should anyway be suspended for some reason; if not, then puts the transaction and the query thread to the lock wait state and inserts a waiting request for a record lock to the lock queue. Sets the requested mode lock on the record.

Parameters

[in]	duration	If equal to AT_LEAST_STATEMENT, then makes sure that the lock will be kept around and inherited for at least the duration of current statement. If equal to REGULAR the life-cycle of the lock will depend on isolation level rules.
[in]	block	buffer block of rec
[in]	rec	user record or page supremum record which should be read or passed over by a read cursor
[in]	index	secondary index
[in]	offsets	rec_get_offsets(rec, index)
[in]	sel_mode	select mode: SELECT_ORDINARY, SELECT_SKIP_LOKCED, or SELECT_NO_WAIT
[in]	mode	mode of the lock which the read cursor should set on records: LOCK_S or LOCK_X; the latter is possible in SELECT FOR UPDATE
[in]	gap_mode	LOCK_ORDINARY, LOCK_GAP, or LOCK_REC_NOT_GAP
[in,out]	thr	query thread

Returns: DB_SUCCESS, DB_SUCCESS_LOCKED_REC, DB_LOCK_WAIT, DB_DEADLOCK, DB_SKIP_LOCKED, or DB_LOCK_NOWAIT

◆ lock_clust_rec_read_check_and_lock_alt()

dberr_t lock_clust_rec_read_check_and_lock_alt	(	const buf_block_t *	block,
		const rec_t *	rec,
		dict_index_t *	index,
		lock_mode	mode,
		ulint	gap_mode,
		que_thr_t *	thr
	)

Checks if locks of other transactions prevent an immediate read, or passing over by a read cursor, of a clustered index record.

If they do, first tests if the query thread should anyway be suspended for some reason; if not, then puts the transaction and the query thread to the lock wait state and inserts a waiting request for a record lock to the lock queue. Sets the requested mode lock on the record. This is an alternative version of lock_clust_rec_read_check_and_lock() that does not require the parameter "offsets".

Returns: DB_SUCCESS, DB_LOCK_WAIT, or DB_DEADLOCK in: query thread

If they do, first tests if the query thread should anyway be suspended for some reason; if not, then puts the transaction and the query thread to the lock wait state and inserts a waiting request for a record lock to the lock queue. Sets the requested mode lock on the record. This is an alternative version of lock_clust_rec_read_check_and_lock() that does not require the parameter "offsets".

Returns: DB_SUCCESS, DB_LOCK_WAIT, or DB_DEADLOCK

Parameters

block	in: buffer block of rec
rec	in: user record or page supremum record which should be read or passed over by a read cursor
index	in: clustered index
mode	in: mode of the lock which the read cursor should set on records: LOCK_S or LOCK_X; the latter is possible in SELECT FOR UPDATE
gap_mode	in: LOCK_ORDINARY, LOCK_GAP, or LOCK_REC_NOT_GAP
thr	in: query thread

◆ lock_find_record_lock_by_guid()

const lock_t * lock_find_record_lock_by_guid	(	page_id_t	page_id,
		const lock_guid_t &	guid
	)

Inspect the lock queues associated with the given page_id in search for a lock which has guid equal to the given one.

Caller should hold a latch on shard containing locks for this page.

Parameters

[in]	page_id	the id of the page, for which we expect the lock
[in]	guid	the guid of the lock we seek for

Returns: the lock with a given guid or nullptr if no such lock

◆ lock_find_table_lock_by_guid()

const lock_t * lock_find_table_lock_by_guid	(	const dict_table_t *	table,
		const lock_guid_t &	guid
	)

Inspect the lock queue associated with the given table in search for a lock which has guid equal to the given one.

Caller should hold a latch on the shard containing this table's locks.

Parameters

[in]	table	the table, for which we expect the lock
[in]	guid	the guid of the lock we seek for

Returns: the lock with a given guid or nullptr if no such lock

◆ lock_get_min_heap_no()

static ulint lock_get_min_heap_no ( const buf_block_t * block )

inlinestatic

Gets the heap_no of the smallest user record on a page.

Returns: heap_no of smallest user record, or PAGE_HEAP_NO_SUPREMUM in: buffer block

◆ lock_get_mode_str()

const char * lock_get_mode_str ( const lock_t * lock )

Gets the mode of a lock in a human readable string.

The string should not be free()'d or modified.

Returns: lock mode in: lock

The string should not be free()'d or modified. This functions is a bit complex for following reasons:

the way it is used in performance schema requires that the memory pointed by the return value is accessible for a long time
the caller never frees the memory
so, we need to maintain a pool of these strings or use string literals
there are many possible combinations of flags and thus it is impractical to maintain the list of all possible literals and if/else logic
moreover, sometimes performance_schema.data_locks is used precisely to investigate some unexpected situation, thus limiting output of this function only to expected combinations of flags might be misleading
Returns
lock mode

Parameters

lock in: lock

◆ lock_get_psi_event()

void lock_get_psi_event	(	const lock_t *	lock,
		ulonglong *	thread_id,
		ulonglong *	event_id
	)

Get the performance schema event (thread_id, event_id) that created the lock.

Parameters

[in]	lock	Lock
[out]	thread_id	Thread ID that created the lock
[out]	event_id	Event ID that created the lock

◆ lock_get_size()

ulint lock_get_size ( void )

Gets the size of a lock struct.

Returns: size in bytes

◆ lock_get_table_id()

table_id_t lock_get_table_id ( const lock_t * lock )

Gets the id of the table on which the lock is.

Returns: id of the table in: lock; id of the table

Parameters

lock in: lock

◆ lock_get_table_name()

const table_name_t & lock_get_table_name ( const lock_t * lock )

Determine which table a lock is associated with.

Parameters

[in] lock the lock

Returns: name of the table

◆ lock_get_trx_id()

trx_id_t lock_get_trx_id ( const lock_t * lock )

Gets the id of the transaction owning a lock.

Parameters

[in] lock A lock of the transaction we are interested in

Returns: the transaction's id

◆ lock_get_type()

uint32_t lock_get_type ( const lock_t * lock )

Gets the type of a lock.

Non-inline version for using outside of the lock module.

Returns: LOCK_TABLE or LOCK_REC in: lock

Non-inline version for using outside of the lock module.

Returns: LOCK_TABLE or LOCK_REC

Parameters

lock in: lock

◆ lock_get_type_str()

const char * lock_get_type_str ( const lock_t * lock )

Gets the type of a lock in a human readable string.

The string should not be free()'d or modified.

Returns: lock type in: lock

The string should not be free()'d or modified.

Returns: lock type

Parameters

lock in: lock

◆ lock_has_to_wait()

bool lock_has_to_wait	(	const lock_t *	lock1,
		const lock_t *	lock2
	)

Checks if a lock request lock1 has to wait for request lock2.

Parameters

[in]	lock1	A waiting lock
[in]	lock2	Another lock; NOTE that it is assumed that this has a lock bit set on the same record as in lock1 if the locks are record lock

Returns: true if lock1 has to wait for lock2 to be removed

◆ lock_is_waiting()

bool lock_is_waiting ( const lock_t & lock )

Checks if the lock is waiting (as opposed to granted).

Caller should hold a latch on shard containging the lock in order for this check to be meaningful.

Parameters

[in] lock the lock to inspect

Returns: true iff the lock is waiting

◆ lock_make_trx_hit_list()

void lock_make_trx_hit_list	(	trx_t *	trx,
		hit_list_t &	hit_list
	)

Iterate over the granted locks which conflict with trx->lock.wait_lock and prepare the hit list for ASYNC Rollback.

If the transaction is waiting for some other lock then wake up with deadlock error. Currently we don't mark following transactions for ASYNC Rollback.

Read only transactions
Background transactions
Other High priority transactions
Parameters

[in] trx High Priority transaction

[in,out] hit_list List of transactions which need to be rolled back

◆ lock_move_rec_list_end()

void lock_move_rec_list_end	(	const buf_block_t *	new_block,
		const buf_block_t *	block,
		const rec_t *	rec
	)

Moves the explicit locks on user records to another page if a record list end is moved to another page.

Parameters

[in]	new_block	Index page to move to
[in]	block	Index page
[in,out]	rec	Record on page: this is the first record moved

◆ lock_move_rec_list_start()

void lock_move_rec_list_start	(	const buf_block_t *	new_block,
		const buf_block_t *	block,
		const rec_t *	rec,
		const rec_t *	old_end
	)

Moves the explicit locks on user records to another page if a record list start is moved to another page.

Parameters

[in]	new_block	Index page to move to
[in]	block	Index page
[in,out]	rec	Record on page: this is the first record not copied
[in]	old_end	Old previous-to-last record on new_page before the records were copied

◆ lock_move_reorganize_page()

void lock_move_reorganize_page	(	const buf_block_t *	block,
		const buf_block_t *	oblock
	)

Updates the lock table when we have reorganized a page.

NOTE: we copy also the locks set on the infimum of the page; the infimum may carry locks if an update of a record is occurring on the page, and its locks were temporarily stored on the infimum. in: copy of the old, not reorganized page

NOTE: we copy also the locks set on the infimum of the page; the infimum may carry locks if an update of a record is occurring on the page, and its locks were temporarily stored on the infimum.

Parameters

block	in: old index page, now reorganized
oblock	in: copy of the old, not reorganized page

◆ lock_number_of_rows_locked()

ulint lock_number_of_rows_locked ( const trx_lock_t * trx_lock )

Return approximate number or record locks (bits set in the bitmap) for this transaction.

Since delete-marked records may be removed, the record count will not be precise. The caller must be holding exclusive global lock_sys latch.

Parameters

[in] trx_lock transaction locks

◆ lock_number_of_tables_locked()

ulint lock_number_of_tables_locked ( const trx_t * trx )

Return the number of table locks for a transaction.

The caller must be holding trx->mutex.

Parameters

[in] trx the transaction for which we want the number of table locks

◆ lock_on_statement_end()

void lock_on_statement_end ( trx_t * trx )

Called to inform lock-sys that a statement processing for a trx has just finished.

Parameters

[in] trx transaction which has finished processing a statement

◆ lock_print_info_all_transactions()

void lock_print_info_all_transactions ( FILE * file )

Prints info of locks for each transaction.

This function assumes that the caller holds the exclusive global latch and more importantly it may release and reacquire it on behalf of the caller. (This should be fixed in the future).

Parameters

[in,out] file the file where to print

◆ lock_print_info_summary()

void lock_print_info_summary ( FILE * file )

Prints info of locks for all transactions.

Parameters

[in] file file where to print

◆ lock_rec_clear_request_no_wakeup()

bool lock_rec_clear_request_no_wakeup	(	lock_t *	lock,
		uint16_t	heap_no
	)

Reset the nth bit of a record lock.

If this was a wait lock clears the wait flag on it, and marks that the trx no longer waits on it, but doesn't wake up the transaction. This function is meant to be used when lock requests are moved from one place to another, and thus a new (equivalent) lock request will be soon created for the transaction, so there's no point in waking it up.

Parameters

[in,out]	lock	record lock
[in]	heap_no	index of the bit that will be reset

Returns: false iff the bit was already cleared before the call

◆ lock_rec_convert_impl_to_expl()

void lock_rec_convert_impl_to_expl	(	const buf_block_t *	block,
		const rec_t *	rec,
		dict_index_t *	index,
		const ulint *	offsets
	)

If a transaction has an implicit x-lock on a record, but no explicit x-lock set on the record, sets one for it.

Parameters

[in]	block	buffer block of rec
[in]	rec	user record on page
[in]	index	index of record
[in]	offsets	rec_get_offsets(rec, index)

◆ lock_rec_discard()

void lock_rec_discard ( lock_t * in_lock )

Removes a record lock request, waiting or granted, from the queue.

in: record lock object: all record locks which are contained in this lock object are removed

Parameters

[in] in_lock record lock object: all record locks which are contained in this lock object are removed

◆ lock_rec_expl_exist_on_page()

bool lock_rec_expl_exist_on_page ( const page_id_t & page_id )

Determines if there are explicit record locks on a page.

Parameters

[in] page_id space id and page number

Returns: true iff an explicit record lock on the page exists

◆ lock_rec_find_next_set_bit()

ulint lock_rec_find_next_set_bit	(	const lock_t *	lock,
		ulint	heap_no
	)

Looks for the next set bit in the record lock bitmap.

Parameters

[in]	lock	record lock with at least one bit set
[in]	heap_no	current set bit

Returns: The next bit index == heap number following heap_no, or ULINT_UNDEFINED if none found

◆ lock_rec_find_set_bit()

ulint lock_rec_find_set_bit ( const lock_t * lock )

Looks for a set bit in a record lock bitmap.

Returns ULINT_UNDEFINED, if none found.

Parameters

[in] lock A record lock

Returns: bit index == heap number of the record, or ULINT_UNDEFINED if none found

◆ lock_rec_free_all_from_discard_page()

void lock_rec_free_all_from_discard_page ( const buf_block_t * block )

Removes record lock objects set on an index page which is discarded.

This function does not move locks, or check for waiting locks, therefore the lock bitmaps must already be reset when this function is called. in: page to be discarded

This function does not move locks, or check for waiting locks, therefore the lock bitmaps must already be reset when this function is called.

Parameters

block in: page to be discarded

◆ lock_rec_get_index()

const dict_index_t * lock_rec_get_index ( const lock_t * lock )

For a record lock, gets the index on which the lock is.

Returns: index in: lock; index

Parameters

lock in: lock

◆ lock_rec_get_index_name()

const char * lock_rec_get_index_name ( const lock_t * lock )

For a record lock, gets the name of the index on which the lock is.

The string should not be free()'d or modified.

Returns: name of the index in: lock

The string should not be free()'d or modified.

Returns: name of the index

Parameters

lock in: lock

◆ lock_rec_get_page_id()

page_id_t lock_rec_get_page_id ( const lock_t * lock )

For a record lock, gets the tablespace number and page number on which the lock is.

Returns: tablespace number in: lock

◆ lock_rec_hash_value()

static uint64_t lock_rec_hash_value ( const page_id_t & page_id )

inlinestatic

Calculates the hash value of a page file address: used in inserting or searching for a lock in the hash table or getting global shard index.

Parameters

page_id specifies the page

Returns: hash value

◆ lock_rec_insert_check_and_lock()

dberr_t lock_rec_insert_check_and_lock	(	ulint	flags,
		const rec_t *	rec,
		buf_block_t *	block,
		dict_index_t *	index,
		que_thr_t *	thr,
		mtr_t *	mtr,
		bool *	inherit
	)

Checks if locks of other transactions prevent an immediate insert of a record.

If they do, first tests if the query thread should anyway be suspended for some reason; if not, then puts the transaction and the query thread to the lock wait state and inserts a waiting request for a gap x-lock to the lock queue.

Returns: DB_SUCCESS, DB_LOCK_WAIT, or DB_DEADLOCK out: set to true if the new inserted record maybe should inherit LOCK_GAP type locks from the successor record

If they do, first tests if the query thread should anyway be suspended for some reason; if not, then puts the transaction and the query thread to the lock wait state and inserts a waiting request for a gap x-lock to the lock queue.

Returns: DB_SUCCESS, DB_LOCK_WAIT, or DB_DEADLOCK

Parameters

flags	in: if BTR_NO_LOCKING_FLAG bit is set, does nothing
rec	in: record after which to insert
block	in/out: buffer block of rec
index	in: index
thr	in: query thread
mtr	in/out: mini-transaction
inherit	out: set to true if the new inserted record maybe should inherit LOCK_GAP type locks from the successor record

◆ lock_rec_reset_and_inherit_gap_locks()

void lock_rec_reset_and_inherit_gap_locks	(	const buf_block_t *	heir_block,
		const buf_block_t *	block,
		ulint	heir_heap_no,
		ulint	heap_no
	)

Resets the original locks on heir and replaces them with gap type locks inherited from rec.

Parameters

[in]	heir_block	Block containing the record which inherits
[in]	block	Block containing the record from which inherited; does not reset the locks on this record
[in]	heir_heap_no	Heap_no of the inheriting record
[in]	heap_no	Heap_no of the donating record

◆ lock_rec_restore_from_page_infimum()

void lock_rec_restore_from_page_infimum	(	const buf_block_t *	block,
		const rec_t *	rec,
		const buf_block_t *	donator
	)

Restores the state of explicit lock requests on a single record, where the state was stored on the infimum of the page.

Parameters

[in]	block	Buffer block containing rec
[in]	rec	Record whose lock state is restored
[in]	donator	Page (rec is not necessarily on this page) whose infimum stored the lock state; lock bits are reset on the infimum

◆ lock_rec_store_on_page_infimum()

void lock_rec_store_on_page_infimum	(	const buf_block_t *	block,
		const rec_t *	rec
	)

Stores on the page infimum record the explicit locks of another record.

This function is used to store the lock state of a record when it is updated and the size of the record changes in the update. The record is in such an update moved, perhaps to another page. The infimum record acts as a dummy carrier record, taking care of lock releases while the actual record is being moved. in: record whose lock state is stored on the infimum record of the same page; lock bits are reset on the record

This function is used to store the lock state of a record when it is updated and the size of the record changes in the update. The record is moved in such an update, perhaps to another page. The infimum record acts as a dummy carrier record, taking care of lock releases while the actual record is being moved.

Parameters

block	in: buffer block containing rec
rec	in: record whose lock state is stored on the infimum record of the same page; lock bits are reset on the record

◆ lock_rec_unlock()

void lock_rec_unlock	(	trx_t *	trx,
		const buf_block_t *	block,
		const rec_t *	rec,
		lock_mode	lock_mode
	)

Removes a granted record lock of a transaction from the queue and grants locks to other transactions waiting in the queue if they now are entitled to a lock.

in: LOCK_S or LOCK_X

This function is meant to be used only by row_try_unlock, and it assumes that the lock we are looking for has LOCK_REC_NOT_GAP flag.

Parameters

trx	in/out: transaction that has set a record lock
block	in: buffer block containing rec
rec	in: record
lock_mode	in: LOCK_S or LOCK_X

◆ lock_remove_all_on_table()

void lock_remove_all_on_table	(	dict_table_t *	table,
		bool	remove_also_table_sx_locks
	)

Removes locks on a table to be dropped.

If remove_also_table_sx_locks is true then table-level S and X locks are also removed in addition to other table-level and record-level locks. No lock, that is going to be removed, is allowed to be a wait lock. in: also removes table S and X locks

If remove_also_table_sx_locks is true then table-level S and X locks are also removed in addition to other table-level and record-level locks. No lock, that is going to be removed, is allowed to be a wait lock.

Parameters

table	in: table to be dropped or discarded
remove_also_table_sx_locks	in: also removes table S and X locks

◆ lock_report_trx_id_insanity()

void lock_report_trx_id_insanity	(	trx_id_t	trx_id,
		const rec_t *	rec,
		const dict_index_t *	index,
		const ulint *	offsets,
		trx_id_t	next_trx_id
	)

Reports that a transaction id is insensible, i.e., in the future.

Parameters

[in]	trx_id	Trx id
[in]	rec	User record
[in]	index	Index
[in]	offsets	Rec_get_offsets(rec, index)
[in]	next_trx_id	value received from trx_sys_get_next_trx_id_or_no()

◆ lock_rtr_move_rec_list()

void lock_rtr_move_rec_list	(	const buf_block_t *	new_block,
		const buf_block_t *	block,
		rtr_rec_move_t *	rec_move,
		ulint	num_move
	)

Moves the explicit locks on user records to another page if a record list start is moved to another page.

Parameters

[in]	new_block	Index page to move to
[in]	block	Index page
[in]	rec_move	Recording records moved
[in]	num_move	Num of rec to move

◆ lock_sec_rec_cons_read_sees()

bool lock_sec_rec_cons_read_sees	(	const rec_t *	rec,
		const dict_index_t *	index,
		const ReadView *	view
	)

Checks that a non-clustered index record is seen in a consistent read.

NOTE that a non-clustered index page contains so little information on its modifications that also in the case false, the present version of rec may be the right, but we must check this from the clustered index record.

Returns: true if certainly sees, or false if an earlier version of the clustered index record might be needed in: consistent read view

NOTE that a non-clustered index page contains so little information on its modifications that also in the case false, the present version of rec may be the right, but we must check this from the clustered index record.

Returns: true if certainly sees, or false if an earlier version of the clustered index record might be needed

Parameters

rec	in: user record which should be read or passed over by a read cursor
index	in: index
view	in: consistent read view

◆ lock_sec_rec_modify_check_and_lock()

dberr_t lock_sec_rec_modify_check_and_lock	(	ulint	flags,
		buf_block_t *	block,
		const rec_t *	rec,
		dict_index_t *	index,
		que_thr_t *	thr,
		mtr_t *	mtr
	)

Checks if locks of other transactions prevent an immediate modify (delete mark or delete unmark) of a secondary index record.

Returns: DB_SUCCESS, DB_LOCK_WAIT, or DB_DEADLOCK in/out: mini-transaction; DB_SUCCESS, DB_LOCK_WAIT, or DB_DEADLOCK

Parameters

flags	in: if BTR_NO_LOCKING_FLAG bit is set, does nothing
block	in/out: buffer block of rec
rec	in: record which should be modified; NOTE: as this is a secondary index, we always have to modify the clustered index record first: see the comment below
index	in: secondary index
thr	in: query thread (can be NULL if BTR_NO_LOCKING_FLAG)
mtr	in/out: mini-transaction

◆ lock_sec_rec_read_check_and_lock()

dberr_t lock_sec_rec_read_check_and_lock	(	lock_duration_t	duration,
		const buf_block_t *	block,
		const rec_t *	rec,
		dict_index_t *	index,
		const ulint *	offsets,
		select_mode	sel_mode,
		lock_mode	mode,
		ulint	gap_mode,
		que_thr_t *	thr
	)

Like lock_clust_rec_read_check_and_lock(), but reads a secondary index record.

Parameters

[in]	duration	If equal to AT_LEAST_STATEMENT, then makes sure that the lock will be kept around and inherited for at least the duration of current statement. If equal to REGULAR the life-cycle of the lock will depend on isolation level rules.
[in]	block	buffer block of rec
[in]	rec	user record or page supremum record which should be read or passed over by a read cursor
[in]	index	secondary index
[in]	offsets	rec_get_offsets(rec, index)
[in]	sel_mode	select mode: SELECT_ORDINARY, SELECT_SKIP_LOKCED, or SELECT_NO_WAIT
[in]	mode	mode of the lock which the read cursor should set on records: LOCK_S or LOCK_X; the latter is possible in SELECT FOR UPDATE
[in]	gap_mode	LOCK_ORDINARY, LOCK_GAP, or LOCK_REC_NOT_GAP
[in,out]	thr	query thread

Returns: DB_SUCCESS, DB_SUCCESS_LOCKED_REC, DB_LOCK_WAIT, DB_DEADLOCK, DB_SKIP_LOCKED, or DB_LOCK_NOWAIT

◆ lock_set_timeout_event()

void lock_set_timeout_event ( )

Set the lock system timeout event.

◆ lock_sys_close()

void lock_sys_close ( void )

Closes the lock system at database shutdown.

◆ lock_sys_create()

void lock_sys_create ( ulint n_cells )

Creates the lock system at database start.

in: number of slots in lock hash table

Parameters

n_cells in: number of slots in lock hash table

◆ lock_sys_resize()

void lock_sys_resize ( ulint n_cells )

Resize the lock hash tables.

Parameters

[in] n_cells number of slots in lock hash table

◆ lock_table()

dberr_t lock_table	(	ulint	flags,
		dict_table_t *	table,
		lock_mode	mode,
		que_thr_t *	thr
	)

Locks the specified database table in the mode given.

If the lock cannot be granted immediately, the query thread is put to wait.

Returns: DB_SUCCESS, DB_LOCK_WAIT, or DB_DEADLOCK in: query thread

If the lock cannot be granted immediately, the query thread is put to wait.

Returns: DB_SUCCESS, DB_LOCK_WAIT, or DB_DEADLOCK

Parameters

flags	in: if BTR_NO_LOCKING_FLAG bit is set, does nothing
table	in/out: database table in dictionary cache
mode	in: lock mode
thr	in: query thread

◆ lock_table_for_trx()

dberr_t lock_table_for_trx	(	dict_table_t *	table,
		trx_t *	trx,
		enum lock_mode	mode
	)

Sets a lock on a table based on the given mode.

Parameters

[in]	table	table to lock
[in,out]	trx	transaction
[in]	mode	LOCK_X or LOCK_S

Returns: error code or DB_SUCCESS.

◆ lock_table_has_locks()

bool lock_table_has_locks ( const dict_table_t * table )

Check if there are any locks (table or rec) against table.

Returned value might be obsolete.

Parameters

[in] table the table

Returns: true if there were any locks held on records in this table or on the table itself at some point in time during the call

The n_rec_locks field might be modified by operation on any page shard. This function is called in contexts where we believe that the number of locks should either be zero or decreasing. For such scenario of usage, we can read the n_rec_locks without any latch and restrict latch just to the table's shard and release it before return, which means true could be a false-positive, but false is certain.

◆ lock_table_ix_resurrect()

void lock_table_ix_resurrect	(	dict_table_t *	table,
		trx_t *	trx
	)

Creates a table IX lock object for a resurrected transaction.

Parameters

[in,out]	table	Table
[in,out]	trx	Transaction

◆ lock_trx_alloc_locks()

void lock_trx_alloc_locks ( trx_t * trx )

Allocate cached locks for the transaction.

Parameters

trx	allocate cached record locks for this transaction

◆ lock_trx_has_rec_x_lock()

bool lock_trx_has_rec_x_lock	(	que_thr_t *	thr,
		const dict_table_t *	table,
		const buf_block_t *	block,
		ulint	heap_no
	)

Check if the transaction holds an exclusive lock on a record.

Parameters

[in]	thr	query thread of the transaction
[in]	table	table to check
[in]	block	buffer block of the record
[in]	heap_no	record heap number

Returns: whether the locks are held

◆ lock_trx_print_wait_and_mvcc_state()

void lock_trx_print_wait_and_mvcc_state	(	FILE *	file,
		const trx_t *	trx
	)

Prints transaction lock wait and MVCC state.

Parameters

[in,out]	file	file where to print
[in]	trx	transaction

◆ lock_trx_release_locks()

void lock_trx_release_locks ( trx_t * trx )

Releases a transaction's locks, and releases possible other transactions waiting because of these locks.

Change the state of the transaction to TRX_STATE_COMMITTED_IN_MEMORY. in/out: transaction

Change the state of the transaction to TRX_STATE_COMMITTED_IN_MEMORY.

Doing an implicit to explicit conversion should not be expensive.

Parameters

trx	in/out: transaction

◆ lock_trx_release_read_locks()

void lock_trx_release_read_locks	(	trx_t *	trx,
		bool	only_gap
	)

Release read locks of a transaction.

It is called during XA prepare to release locks early.

Parameters

[in,out]	trx	transaction
[in]	only_gap	release only GAP locks

◆ lock_unlock_table_autoinc()

void lock_unlock_table_autoinc ( trx_t * trx )

Unlocks AUTO_INC type locks that were possibly reserved by a trx.

This function should be called at the the end of an SQL statement, by the connection thread that owns the transaction (trx->mysql_thd). in/out: transaction

This function should be called at the the end of an SQL statement, by the connection thread that owns the transaction (trx->mysql_thd).

Parameters

trx	in/out: transaction

◆ lock_update_copy_and_discard()

void lock_update_copy_and_discard	(	const buf_block_t *	new_block,
		const buf_block_t *	block
	)

Updates the lock table when a page is copied to another and the original page is removed from the chain of leaf pages, except if page is the root!

Parameters

[in]	new_block	Index page to which copied
[in]	block	Index page; not the root!

◆ lock_update_delete()

void lock_update_delete	(	const buf_block_t *	block,
		const rec_t *	rec
	)

Updates the lock table when a record is removed.

Parameters

[in]	block	Buffer block containing rec
[in]	rec	The record to be removed

◆ lock_update_discard()

void lock_update_discard	(	const buf_block_t *	heir_block,
		ulint	heir_heap_no,
		const buf_block_t *	block
	)

Updates the lock table when a page is discarded.

Parameters

[in]	heir_block	Index page which will inherit the locks
[in]	heir_heap_no	Heap_no of the record which will inherit the locks
[in]	block	Index page which will be discarded

◆ lock_update_insert()

void lock_update_insert	(	const buf_block_t *	block,
		const rec_t *	rec
	)

Updates the lock table when a new user record is inserted.

Parameters

[in]	block	Buffer block containing rec
[in]	rec	The inserted record

Parameters

block	in: buffer block containing rec
rec	in: the inserted record

◆ lock_update_merge_left()

void lock_update_merge_left	(	const buf_block_t *	left_block,
		const rec_t *	orig_pred,
		const buf_block_t *	right_block
	)

Updates the lock table when a page is merged to the left.

Parameters

[in]	left_block	Left page to which merged
[in]	orig_pred	Original predecessor of supremum on the left page before merge
[in]	right_block	Merged index page which will be discarded

◆ lock_update_merge_right()

void lock_update_merge_right	(	const buf_block_t *	right_block,
		const rec_t *	orig_succ,
		const buf_block_t *	left_block
	)

Updates the lock table when a page is merged to the right.

Parameters

[in]	right_block	Right page to which merged
[in]	orig_succ	Original successor of infimum on the right page before merge
[in]	left_block	Merged index page which will be discarded

◆ lock_update_root_raise()

void lock_update_root_raise	(	const buf_block_t *	block,
		const buf_block_t *	root
	)

Updates the lock table when the root page is copied to another in btr_root_raise_and_insert.

Note that we leave lock structs on the root page, even though they do not make sense on other than leaf pages: the reason is that in a pessimistic update the infimum record of the root page will act as a dummy carrier of the locks of the record to be updated. in: root page

Note that we leave lock structs on the root page, even though they do not make sense on other than leaf pages: the reason is that in a pessimistic update the infimum record of the root page will act as a dummy carrier of the locks of the record to be updated.

Parameters

block	in: index page to which copied
root	in: root page

◆ lock_update_split_left()

void lock_update_split_left	(	const buf_block_t *	right_block,
		const buf_block_t *	left_block
	)

Updates the lock table when a page is split to the left.

Parameters

[in]	right_block	Right page
[in]	left_block	Left page

◆ lock_update_split_point()

void lock_update_split_point	(	const buf_block_t *	right_block,
		const buf_block_t *	left_block
	)

Requests the Lock System to update record locks regarding the gap between the last record of the left_page and the first record of the right_page when the caller is about to prepended a new record as the first record on the right page, even though it should "naturally" be inserted as the last record of the left_page according to the information in the higher levels of the index.

That is, we assume that the lowest common ancestor of the left_page and the right_page routes the key of the new record to the left_page, but a heuristic which tries to avoid overflowing the left_page has chosen to prepend the new record to the right_page instead. Said ancestor performs this routing by comparing the key of the record to a "split point" - the key associated with the right_page's subtree, such that all records larger than that split point are to be found in the right_page (or some even further page). Ideally this should be the minimum key in this whole subtree, however due to the way we optimize the DELETE and INSERT operations, we often do not update this information, so that such "split point" can actually be smaller than the real minimum. Still, even if not up-to-date, its value is always correct, in that it really separates the subtrees (keys smaller than "split point" are not in left_page and larger are not in right_page).

The reason this is important to Lock System, is that the gap between the last record on the left_page and the first record on the right_page is represented as two gaps:

The gap between the last record on the left_page and the "split point", represented as the gap before the supremum pseudo-record of the left_page.
The gap between the "split point" and the first record of the right_page, represented as the gap before the first user record of the right_page.

Thus, inserting the new record, and subsequently adjusting "split points" in its ancestors to values smaller or equal to the new records' key, will mean that gap will be sliced at a different place ("moved to the left"): fragment of the 1st gap will now become treated as 2nd. Therefore, Lock System must copy any GRANTED locks from 1st gap to the 2nd gap. Any WAITING locks must be of INSERT_INTENTION type (as no other GAP locks ever wait for anything) and can stay at 1st gap, as their only purpose is to notify the requester they can retry insertion, and there's no correctness requirement to avoid waking them up too soon.

Parameters

[in]	right_block	Right page
[in]	left_block	Left page

◆ lock_update_split_right()

void lock_update_split_right	(	const buf_block_t *	right_block,
		const buf_block_t *	left_block
	)

Updates the lock table when a page is split to the right.

Parameters

[in]	right_block	Right page
[in]	left_block	Left page

◆ lock_validate()

bool lock_validate ( )

Validates the lock system.

Returns: true if ok

◆ lock_wait_mutex_enter()

static void lock_wait_mutex_enter ( )

inlinestatic

Acquire the lock_sys->wait_mutex.

◆ lock_wait_mutex_exit()

static void lock_wait_mutex_exit ( )

inlinestatic

Release the lock_sys->wait_mutex.

◆ lock_wait_mutex_own()

static bool lock_wait_mutex_own ( )

inlinestatic

Test if lock_sys->wait_mutex is owned.

◆ lock_wait_request_check_for_cycles()

void lock_wait_request_check_for_cycles ( )

Notifies the thread which analyzes wait-for-graph that there was at least one new edge added or modified ( trx->blocking_trx has changed ), so that the thread will know it has to analyze it.

◆ lock_wait_suspend_thread()

void lock_wait_suspend_thread ( que_thr_t * thr )

Puts a user OS thread to wait for a lock to be released.

If an error occurs during the wait trx->error_state associated with thr is != DB_SUCCESS when we return. DB_INTERRUPTED, DB_LOCK_WAIT_TIMEOUT and DB_DEADLOCK are possible errors. DB_DEADLOCK is returned if selective deadlock resolution chose this transaction as a victim. in: query thread associated with the user OS thread

◆ lock_wait_timeout_thread()

void lock_wait_timeout_thread ( )

A thread which wakes up threads whose lock wait may have lasted too long.

The last time we've checked for timeouts.

Variable Documentation

◆ innobase_deadlock_detect

bool innobase_deadlock_detect

extern

◆ LOCK_GAP

constexpr uint32_t LOCK_GAP = 512

constexpr

when this bit is set, it means that the lock holds only on the gap before the record; for instance, an x-lock on the gap does not give permission to modify the record on which the bit is set; locks of this type are created when records are removed from the index chain of records

◆ LOCK_INSERT_INTENTION

constexpr uint32_t LOCK_INSERT_INTENTION = 2048

constexpr

this bit is set when we place a waiting gap type record lock request in order to let an insert of an index record to wait until there are no conflicting locks by other transactions on the gap; note that this flag remains set when the waiting lock is granted, or if the lock is inherited to a neighboring record

◆ LOCK_MODE_MASK

constexpr uint32_t LOCK_MODE_MASK = 0xF

constexpr

Lock modes and types.

mask used to extract mode from the type_mode field in a lock

◆ LOCK_ORDINARY

constexpr uint32_t LOCK_ORDINARY = 0

constexpr

this flag denotes an ordinary next-key lock in contrast to LOCK_GAP or LOCK_REC_NOT_GAP

◆ LOCK_PRDT_PAGE

constexpr uint32_t LOCK_PRDT_PAGE = 16384

constexpr

Page lock.

◆ LOCK_PREDICATE

constexpr uint32_t LOCK_PREDICATE = 8192

constexpr

Predicate lock.

◆ LOCK_REC

constexpr uint32_t LOCK_REC = 32

constexpr

record lock

◆ LOCK_REC_NOT_GAP

constexpr uint32_t LOCK_REC_NOT_GAP = 1024

constexpr

this bit means that the lock is only on the index record and does NOT block inserts to the gap before the index record; this is used in the case when we retrieve a record with a unique key, and is also used in locking plain SELECTs (not part of UPDATE or DELETE) when the user has set the READ COMMITTED isolation level

◆ lock_sys

lock_sys_t* lock_sys

extern

The lock system.

◆ LOCK_TABLE

constexpr uint32_t LOCK_TABLE = 16

constexpr

Lock types.

table lock

◆ LOCK_TYPE_MASK

constexpr uint32_t LOCK_TYPE_MASK = 0xF0UL

constexpr

mask used to extract lock type from the type_mode field in a lock

◆ LOCK_WAIT

constexpr uint32_t LOCK_WAIT = 256

constexpr

Waiting lock flag; when set, it means that the lock has not yet been granted, it is just waiting for its turn in the wait queue.

[in]	trx	High Priority transaction
[in,out]	hit_list	List of transactions which need to be rolled back

Classes

Namespaces

Typedefs

Enumerations

Functions

Variables

Detailed Description

Typedef Documentation

◆ Lock_mutex

Enumeration Type Documentation

◆ lock_duration_t

Function Documentation

◆ lock_cancel_if_waiting_and_release()

◆ lock_check_trx_id_sanity()

◆ lock_clust_rec_cons_read_sees()

◆ lock_clust_rec_modify_check_and_lock()

◆ lock_clust_rec_read_check_and_lock()

◆ lock_clust_rec_read_check_and_lock_alt()

◆ lock_find_record_lock_by_guid()

◆ lock_find_table_lock_by_guid()

◆ lock_get_min_heap_no()

◆ lock_get_mode_str()

◆ lock_get_psi_event()

◆ lock_get_size()

◆ lock_get_table_id()

◆ lock_get_table_name()

◆ lock_get_trx_id()

◆ lock_get_type()

◆ lock_get_type_str()

◆ lock_has_to_wait()

◆ lock_is_waiting()

◆ lock_make_trx_hit_list()

◆ lock_move_rec_list_end()

◆ lock_move_rec_list_start()

◆ lock_move_reorganize_page()

◆ lock_number_of_rows_locked()

◆ lock_number_of_tables_locked()

◆ lock_on_statement_end()

◆ lock_print_info_all_transactions()

◆ lock_print_info_summary()

◆ lock_rec_clear_request_no_wakeup()

◆ lock_rec_convert_impl_to_expl()

◆ lock_rec_discard()

◆ lock_rec_expl_exist_on_page()

◆ lock_rec_find_next_set_bit()

◆ lock_rec_find_set_bit()

◆ lock_rec_free_all_from_discard_page()

◆ lock_rec_get_index()

◆ lock_rec_get_index_name()

◆ lock_rec_get_page_id()

◆ lock_rec_hash_value()

◆ lock_rec_insert_check_and_lock()

◆ lock_rec_reset_and_inherit_gap_locks()

◆ lock_rec_restore_from_page_infimum()

◆ lock_rec_store_on_page_infimum()

◆ lock_rec_unlock()

◆ lock_remove_all_on_table()

◆ lock_report_trx_id_insanity()

◆ lock_rtr_move_rec_list()

◆ lock_sec_rec_cons_read_sees()

◆ lock_sec_rec_modify_check_and_lock()

◆ lock_sec_rec_read_check_and_lock()

◆ lock_set_timeout_event()

◆ lock_sys_close()

◆ lock_sys_create()

◆ lock_sys_resize()

◆ lock_table()

◆ lock_table_for_trx()

◆ lock_table_has_locks()

◆ lock_table_ix_resurrect()

◆ lock_trx_alloc_locks()

◆ lock_trx_has_rec_x_lock()

◆ lock_trx_print_wait_and_mvcc_state()

◆ lock_trx_release_locks()

◆ lock_trx_release_read_locks()

◆ lock_unlock_table_autoinc()

◆ lock_update_copy_and_discard()

◆ lock_update_delete()

◆ lock_update_discard()

◆ lock_update_insert()