Query graph. More...

#include <stddef.h>
#include "dict0crea.h"
#include "eval0eval.h"
#include "eval0proc.h"
#include "ha_prototypes.h"
#include "lock0lock.h"
#include "log0chkp.h"
#include "pars0types.h"
#include "que0que.h"
#include "row0ins.h"
#include "row0purge.h"
#include "row0sel.h"
#include "row0undo.h"
#include "row0upd.h"
#include "trx0roll.h"
#include "trx0trx.h"
#include "usr0sess.h"
#include "my_dbug.h"

Functions
static void	que_thr_move_to_run_state (que_thr_t *thr)
	Moves a thread from another state to the QUE_THR_RUNNING state. More...

que_fork_t *	que_fork_create (que_t graph, que_node_t parent, ulint fork_type, mem_heap_t *heap)
	Creates a query graph fork node. More...

que_thr_t *	que_thr_create (que_fork_t parent, mem_heap_t heap, row_prebuilt_t *prebuilt)
	Creates a query graph thread node. More...

que_thr_t *	que_thr_end_lock_wait (trx_t *trx)
	Moves a suspended query thread to the QUE_THR_RUNNING state and may release a worker thread to execute it. More...

static void	que_thr_init_command (que_thr_t *thr)
	Inits a query thread for a command. More...

que_thr_t *	que_fork_scheduler_round_robin (que_fork_t fork, que_thr_t thr)
	Round robin scheduler. More...

que_thr_t *	que_fork_start_command (que_fork_t *fork)
	Starts execution of a command in a query fork. More...

static void	que_graph_free_stat_list (que_node_t *node)
	Calls que_graph_free_recursive for statements in a statement list. More...

void	que_graph_free_recursive (que_node_t *node)
	Frees a query graph, but not the heap where it was created. More...

void	que_graph_free (que_t *graph)
	Frees a query graph. More...

static que_thr_t *	que_thr_node_step (que_thr_t *thr)
	Performs an execution step on a thr node. More...

bool	que_thr_stop (que_thr_t *thr)
	Stops a query thread if graph or trx is in a state requiring it. More...

static void	que_thr_dec_refer_count (que_thr_t thr, que_thr_t *next_thr)
	Decrements the query thread reference counts in the query graph and the transaction. More...

void	que_thr_stop_for_mysql (que_thr_t *thr)
	A patch for MySQL used to 'stop' a dummy query thread used in MySQL. More...

void	que_thr_move_to_run_state_for_mysql (que_thr_t thr, trx_t trx)
	Moves a thread from another state to the QUE_THR_RUNNING state. More...

void	que_thr_stop_for_mysql_no_error (que_thr_t thr, trx_t trx)
	A patch for MySQL used to 'stop' a dummy query thread used in MySQL select, when there is no error or lock wait. More...

que_node_t *	que_node_get_containing_loop_node (que_node_t *node)
	Get the first containing loop node (e.g. More...

static const char *	que_node_type_string (const que_node_t *node)
	Gets information of an SQL query graph node. More...

static que_thr_t *	que_thr_step (que_thr_t *thr)
	Performs an execution step on a query thread. More...

static void	que_run_threads_low (que_thr_t *thr)
	Run a query thread until it finishes or encounters e.g. More...

void	que_run_threads (que_thr_t *thr)
	Run a query thread. More...

dberr_t	que_eval_sql (pars_info_t info, const char sql, trx_t *trx)
	Evaluate the given SQL. More...

void	que_init (void)
	Initialise the query sub-system. More...

void	que_close (void)
	Close the query sub-system. More...

Detailed Description

Query graph.

Created 5/27/1996 Heikki Tuuri

Function Documentation

◆ que_close()

void que_close ( void )

Close the query sub-system.

◆ que_eval_sql()

dberr_t que_eval_sql	(	pars_info_t *	info,
		const char *	sql,
		trx_t *	trx
	)

Evaluate the given SQL.

Parameters

[in]	info	Info struct, or nullptr.
[in]	sql	SQL string.
[in]	trx	Transaction.

Returns: error code or DB_SUCCESS

◆ que_fork_create()

que_fork_t * que_fork_create	(	que_t *	graph,
		que_node_t *	parent,
		ulint	fork_type,
		mem_heap_t *	heap
	)

Creates a query graph fork node.

Returns: own: fork node

Parameters

graph	in: graph, if NULL then this fork node is assumed to be the graph root
parent	in: parent node
fork_type	in: fork type
heap	in: memory heap where created

◆ que_fork_scheduler_round_robin()

que_thr_t * que_fork_scheduler_round_robin	(	que_fork_t *	fork,
		que_thr_t *	thr
	)

Round robin scheduler.

Returns: a query thread of the graph moved to QUE_THR_RUNNING state, or NULL; the query thread should be executed by que_run_threads by the caller

Parameters

fork	in: a query fork
thr	in: current pos

◆ que_fork_start_command()

que_thr_t * que_fork_start_command ( que_fork_t * fork )

Starts execution of a command in a query fork.

Picks a query thread which is not in the QUE_THR_RUNNING state and moves it to that state. If none can be chosen, a situation which may arise in parallelized fetches, NULL is returned.

Returns: a query thread of the graph moved to QUE_THR_RUNNING state, or NULL; the query thread should be executed by que_run_threads by the caller

Parameters

fork	in: a query fork

◆ que_graph_free()

void que_graph_free ( que_t * graph )

Frees a query graph.

in: query graph; we assume that the memory heap where this graph was created is private to this graph: if not, then use que_graph_free_recursive and free the heap afterwards!

Parameters

graph in: query graph; we assume that the memory heap where this graph was created is private to this graph: if not, then use que_graph_free_recursive and free the heap afterwards!

◆ que_graph_free_recursive()

void que_graph_free_recursive ( que_node_t * node )

Frees a query graph, but not the heap where it was created.

Does not free explicit cursor declarations, they are freed in que_graph_free.

Parameters

node	in: query graph node

◆ que_graph_free_stat_list()

static void que_graph_free_stat_list ( que_node_t * node )

static

Calls que_graph_free_recursive for statements in a statement list.

Parameters

node	in: first query graph node in the list

◆ que_init()

void que_init ( void )

Initialise the query sub-system.

◆ que_node_get_containing_loop_node()

que_node_t * que_node_get_containing_loop_node ( que_node_t * node )

Get the first containing loop node (e.g.

while_node_t or for_node_t) for the given node, or NULL if the node is not within a loop.

Returns: containing loop node, or NULL.

Parameters

node in: node

◆ que_node_type_string()

static const char * que_node_type_string ( const que_node_t * node )

static

Gets information of an SQL query graph node.

Returns: type description

Parameters

node	in: query graph node

◆ que_run_threads()

void que_run_threads ( que_thr_t * thr )

Run a query thread.

Handles lock waits.

Parameters

thr	in: query thread

◆ que_run_threads_low()

static void que_run_threads_low ( que_thr_t * thr )

static

Run a query thread until it finishes or encounters e.g.

a lock wait.

Parameters

thr	in: query thread

◆ que_thr_create()

que_thr_t * que_thr_create	(	que_fork_t *	parent,
		mem_heap_t *	heap,
		row_prebuilt_t *	prebuilt
	)

Creates a query graph thread node.

Parameters

[in]	parent	parent node, i.e., a fork node
[in]	heap	memory heap where created
[in]	prebuilt	row prebuilt structure

Returns: own: query thread node

◆ que_thr_dec_refer_count()

static void que_thr_dec_refer_count	(	que_thr_t *	thr,
		que_thr_t **	next_thr
	)

static

Decrements the query thread reference counts in the query graph and the transaction.

NOTE ***: This and que_thr_stop_for_mysql are the only functions where the reference count can be decremented and this function may only be called from inside que_run_threads! These restrictions exist to make the rollback code easier to maintain.

Parameters

thr	in: query thread
next_thr	in/out: next query thread to run; if the value which is passed in is a pointer to a NULL pointer, then the calling function can start running a new query thread

◆ que_thr_end_lock_wait()

que_thr_t * que_thr_end_lock_wait ( trx_t * trx )

Moves a suspended query thread to the QUE_THR_RUNNING state and may release a worker thread to execute it.

Moves a suspended query thread to the QUE_THR_RUNNING state and release a worker thread to execute it.

This function should be used to end the wait state of a query thread waiting for a lock or a stored procedure completion.

Returns: the query thread that needs to be released.

Parameters

trx	in: transaction with que_state in QUE_THR_LOCK_WAIT

◆ que_thr_init_command()

static void que_thr_init_command ( que_thr_t * thr )

inlinestatic

Inits a query thread for a command.

Parameters

thr	in: query thread

◆ que_thr_move_to_run_state()

static void que_thr_move_to_run_state ( que_thr_t * thr )

static

Moves a thread from another state to the QUE_THR_RUNNING state.

Increments the n_active_thrs counters of the query graph and transaction. NOTE***: This is the only function in which such a transition is allowed to happen! in: an query thread

Increments the n_active_thrs counters of the query graph and transaction if thr was not active. NOTE***: This and ..._mysql are the only functions in which such a transition is allowed to happen!

Parameters

thr	in: an query thread

◆ que_thr_move_to_run_state_for_mysql()

void que_thr_move_to_run_state_for_mysql	(	que_thr_t *	thr,
		trx_t *	trx
	)

Moves a thread from another state to the QUE_THR_RUNNING state.

Increments the n_active_thrs counters of the query graph and transaction if thr was not active.

Parameters

thr	in: an query thread
trx	in: transaction

◆ que_thr_node_step()

static que_thr_t * que_thr_node_step ( que_thr_t * thr )

static

Performs an execution step on a thr node.

Returns: query thread to run next, or NULL if none

Parameters

thr	in: query thread where run_node must be the thread node itself

◆ que_thr_step()

static que_thr_t * que_thr_step ( que_thr_t * thr )

inlinestatic

Performs an execution step on a query thread.

Returns: query thread to run next: it may differ from the input parameter if, e.g., a subprocedure call is made

Parameters

thr	in: query thread

◆ que_thr_stop()

bool que_thr_stop ( que_thr_t * thr )

Stops a query thread if graph or trx is in a state requiring it.

The conditions are tested in the order (1) graph, (2) trx. Caller must hold the trx mutex.

Parameters

[in,out] thr query thread

Returns: true if stopped

◆ que_thr_stop_for_mysql()

void que_thr_stop_for_mysql ( que_thr_t * thr )

A patch for MySQL used to 'stop' a dummy query thread used in MySQL.

The query thread is stopped and made inactive, except in the case where it was put to the lock wait state in lock0lock.cc, but the lock has already been granted or the transaction chosen as a victim in deadlock resolution.

Parameters

thr	in: query thread

◆ que_thr_stop_for_mysql_no_error()

void que_thr_stop_for_mysql_no_error	(	que_thr_t *	thr,
		trx_t *	trx
	)

A patch for MySQL used to 'stop' a dummy query thread used in MySQL select, when there is no error or lock wait.

Parameters

[in]	thr	Query thread
[in]	trx	Transaction

Functions

Detailed Description

Function Documentation

◆ que_close()

◆ que_eval_sql()

◆ que_fork_create()

◆ que_fork_scheduler_round_robin()

◆ que_fork_start_command()

◆ que_graph_free()

◆ que_graph_free_recursive()

◆ que_graph_free_stat_list()

◆ que_init()

◆ que_node_get_containing_loop_node()

◆ que_node_type_string()

◆ que_run_threads()

◆ que_run_threads_low()

◆ que_thr_create()

◆ que_thr_dec_refer_count()

◆ que_thr_end_lock_wait()

◆ que_thr_init_command()

◆ que_thr_move_to_run_state()

◆ que_thr_move_to_run_state_for_mysql()

◆ que_thr_node_step()

◆ que_thr_step()

◆ que_thr_stop()

◆ que_thr_stop_for_mysql()

◆ que_thr_stop_for_mysql_no_error()