For each client connection we create a separate thread with THD serving as a thread/connection descriptor. More...

#include <sql_class.h>

Inheritance diagram for THD:

Classes
class	Attachable_trx
	Class representing read-only attachable transaction, encapsulates knowledge how to backup state of current transaction, start read-only attachable transaction in SE, finalize it and then restore state of original transaction back. More...

class	Attachable_trx_rw
	A derived from THD::Attachable_trx class allows updates in the attachable transaction. More...

class	Query_plan
	Query plan for EXPLAINable commands, should be locked with LOCK_query_plan before using. More...

struct	Transaction_state
	An utility struct for `Attachable_trx`. More...

Public Types
enum	binlog_filter_state { BINLOG_FILTER_UNKNOWN, BINLOG_FILTER_CLEAR, BINLOG_FILTER_SET }

enum	enum_reset_lex { RESET_LEX, DO_NOT_RESET_LEX }

enum	Commit_error { CE_NONE = 0, CE_FLUSH_ERROR, CE_SYNC_ERROR, CE_COMMIT_ERROR, CE_ERROR_COUNT }

enum	killed_state { NOT_KILLED = 0, KILL_CONNECTION = ER_SERVER_SHUTDOWN, KILL_QUERY = ER_QUERY_INTERRUPTED, KILL_TIMEOUT = ER_QUERY_TIMEOUT, KILLED_NO_VALUE }

enum	enum_binlog_query_type { ROW_QUERY_TYPE, STMT_QUERY_TYPE, QUERY_TYPE_COUNT }

Public Types inherited from Query_arena
enum	enum_state { STMT_INITIALIZED = 0, STMT_INITIALIZED_FOR_SP = 1, STMT_PREPARED = 2, STMT_CONVENTIONAL_EXECUTION = 3, STMT_EXECUTED = 4, STMT_ERROR = -1 }

Public Types inherited from Open_tables_state
enum	enum_flags { BACKUPS_AVAIL = (1U << 0), SYSTEM_TABLES = (1U << 1) }

Public Member Functions
dd::cache::Dictionary_client *	dd_client () const

bool	is_binlog_applier ()
	The function checks whether the thread is processing queries from binlog, as automatically generated by mysqlbinlog. More...

void	rpl_detach_engine_ha_data ()
	When the thread is a binlog or slave applier it detaches the engine ha_data associated with it and memorizes the fact of that. More...

void	rpl_reattach_engine_ha_data ()
	When the thread is a binlog or slave applier it reattaches the engine ha_data associated with it and memorizes the fact of that. More...

bool	rpl_unflag_detached_engine_ha_data ()

void	reset_for_next_command ()

void	clear_current_query_costs ()
	Clear the query costs attributes for the current query. More...

void	save_current_query_costs ()
	Save the current query costs attributes in the thread session status. More...

void	lock_query_plan ()
	Locks the query plan of this THD. More...

void	unlock_query_plan ()

Security_context *	security_context () const

void	set_security_context (Security_context *sctx)

Protocol *	get_protocol ()

SSL_handle	get_ssl () const

Protocol_classic *	get_protocol_classic () const
	Asserts that the protocol is of type text or binary and then returns the m_protocol casted to Protocol_classic. More...

const LEX_CSTRING &	catalog () const

void	set_catalog (const LEX_CSTRING &catalog)

void	enter_stage (const PSI_stage_info stage, PSI_stage_info old_stage, const char calling_func, const char calling_file, const unsigned int calling_line)

const char *	get_proc_info () const

Ha_data *	get_ha_data (int slot)
	Retrieve Ha_data for a given slot. More...

void	backup_ha_data (Prealloced_array< Ha_data, PREALLOC_NUM_HA > *backup)
	Copy ha_data into the provided argument. More...

void	restore_ha_data (const Prealloced_array< Ha_data, PREALLOC_NUM_HA > &backup)
	Restore ha_data from the provided backup copy. More...

void	set_next_event_pos (const char *_filename, ulonglong _pos)

void	clear_next_event_pos ()

int	binlog_setup_trx_data ()

int	binlog_write_table_map (TABLE *table, bool is_transactional, bool binlog_rows_query)
	This function writes a table map to the binary log. More...

int	binlog_write_row (TABLE table, bool is_transactional, const uchar new_data, const uchar *extra_row_info)

int	binlog_delete_row (TABLE table, bool is_transactional, const uchar old_data, const uchar *extra_row_info)

int	binlog_update_row (TABLE table, bool is_transactional, const uchar old_data, const uchar new_data, const uchar extra_row_info)

void	binlog_prepare_row_images (TABLE *table)

void	set_server_id (uint32 sid)

template<class RowsEventT >
Rows_log_event *	binlog_prepare_pending_rows_event (TABLE table, uint32 serv_id, size_t needed, bool is_transactional, RowsEventT hint, const uchar *extra_row_info)

Rows_log_event *	binlog_get_pending_rows_event (bool is_transactional) const
	This function retrieves a pending row event from a cache which is specified through the parameter `is_transactional`. More...

int	binlog_flush_pending_rows_event (bool stmt_end)

int	binlog_flush_pending_rows_event (bool stmt_end, bool is_transactional)

int	is_current_stmt_binlog_format_row () const
	Determine the binlog format of the current statement. More...

bool	is_current_stmt_binlog_disabled () const
	Determine if binlogging is disabled for this session. More...

bool	is_current_stmt_binlog_row_enabled_with_write_set_extraction () const
	Determine if binloging is enabled in row format and write set extraction is enabled for this session. More...

bool	optimizer_switch_flag (ulonglong flag) const
	Tells whether the given optimizer_switch flag is on. More...

void	reset_binlog_local_stmt_filter ()

void	clear_binlog_local_stmt_filter ()

void	set_binlog_local_stmt_filter ()

binlog_filter_state	get_binlog_local_stmt_filter ()

void	set_skip_readonly_check ()

bool	is_cmd_skip_readonly ()

void	reset_skip_readonly_check ()

void	issue_unsafe_warnings ()
	Auxiliary method used by `binlog_query()` to raise warnings. More...

uint	get_binlog_table_maps () const

void	clear_binlog_table_maps ()

List< char > *	get_binlog_accessed_db_names ()

void	add_to_binlog_accessed_dbs (const char *db)

Transaction_ctx *	get_transaction ()

const Transaction_ctx *	get_transaction () const

void	set_transaction (Transaction_ctx *transaction_ctx)
	Changes the Transaction_ctx instance within THD-object. More...

void	record_first_successful_insert_id_in_cur_stmt (ulonglong id_arg)

ulonglong	read_first_successful_insert_id_in_prev_stmt (void)

void	reset_first_successful_insert_id ()

void	force_one_auto_inc_interval (ulonglong next_id)

longlong	get_row_count_func () const

void	set_row_count_func (longlong row_count_func)

void	set_user_connect (USER_CONN *uc)

const USER_CONN *	get_user_connect ()

void	increment_user_connections_counter ()

void	decrement_user_connections_counter ()

void	increment_con_per_hour_counter ()

void	increment_updates_counter ()

void	increment_questions_counter ()

void	time_out_user_resource_limits ()

ha_rows	get_sent_row_count () const

ha_rows	get_examined_row_count () const

void	set_sent_row_count (ha_rows count)

void	inc_sent_row_count (ha_rows count)

void	inc_examined_row_count (ha_rows count)

void	inc_status_created_tmp_disk_tables ()

void	inc_status_created_tmp_tables ()

void	inc_status_select_full_join ()

void	inc_status_select_full_range_join ()

void	inc_status_select_range ()

void	inc_status_select_range_check ()

void	inc_status_select_scan ()

void	inc_status_sort_merge_passes ()

void	inc_status_sort_range ()

void	inc_status_sort_rows (ha_rows count)

void	inc_status_sort_scan ()

void	set_status_no_index_used ()

void	set_status_no_good_index_used ()

void	set_new_thread_id ()
	Assign a value to m_thread_id by calling Global_THD_manager::get_new_thread_id(). More...

my_thread_id	thread_id () const

bool	is_system_thread () const

bool	is_dd_system_thread () const

bool	is_initialize_system_thread () const

bool	is_bootstrap_system_thread () const

	THD (bool enable_plugins=true)

	~THD ()

void	release_resources ()
	Release most resources, prior to THD destruction. More...

bool	release_resources_done () const

void	init_query_mem_roots ()
	Initialize memory roots necessary for query processing and (!) pre-allocate memory for it. More...

void	cleanup_connection (void)

void	cleanup_after_query ()

bool	store_globals ()

void	restore_globals ()

void	set_active_vio (Vio *vio)

void	set_ssl (Vio *vio)

void	clear_active_vio ()

enum_vio_type	get_vio_type ()

void	shutdown_active_vio ()

void	awake (THD::killed_state state_to_set)
	Awake a thread. More...

void	disconnect (bool server_shutdown=false)
	Disconnect the associated communication endpoint. More...

int	binlog_query (enum_binlog_query_type qtype, const char *query, size_t query_len, bool is_trans, bool direct, bool suppress_use, int errcode)
	Log the current query. More...

void	enter_cond (mysql_cond_t cond, mysql_mutex_t mutex, const PSI_stage_info stage, PSI_stage_info old_stage, const char src_function, const char src_file, int src_line)
	Enter a condition wait. More...

void	exit_cond (const PSI_stage_info stage, const char src_function, const char *src_file, int src_line)
	End a wait on a condition. More...

virtual int	is_killed () const final
	Has the owner thread been killed? More...

virtual THD *	get_thd ()
	Within MDL subsystem this one is only used for DEBUG_SYNC. More...

virtual void	notify_shared_lock (MDL_context_owner *ctx_in_use, bool needs_thr_lock_abort)
	A callback to the server internals that is used to address special cases of the locking protocol. More...

virtual bool	notify_hton_pre_acquire_exclusive (const MDL_key mdl_key, bool victimized)
	Notify/get permission from interested storage engines before acquiring exclusive lock for the key. More...

virtual void	notify_hton_post_release_exclusive (const MDL_key *mdl_key)
	Notify interested storage engines that we have just released exclusive lock for the key. More...

virtual uint	get_rand_seed ()
	Provide thread specific random seed for MDL_context's PRNG. More...

bool	is_strict_mode () const

const CHARSET_INFO *	collation ()

Time_zone *	time_zone ()

time_t	query_start_in_secs () const

timeval	query_start_timeval_trunc (uint decimals)

void	set_time ()

void	set_time (const struct timeval *t)

void	set_time_after_lock ()

bool	is_fsp_truncate_mode () const

void	update_slow_query_status ()
	Evaluate the current time, and if it exceeds the long-query-time setting, mark the query as slow. More...

ulonglong	found_rows (void)

void	update_previous_found_rows ()

bool	in_multi_stmt_transaction_mode () const
	Returns true if session is in a multi-statement transaction mode. More...

bool	in_active_multi_stmt_transaction () const
	true if the session is in a multi-statement transaction mode ( More...

bool	fill_information_schema_tables ()

LEX_CSTRING *	make_lex_string (LEX_CSTRING lex_str, const char str, size_t length, bool allocate_lex_string)

LEX_STRING *	make_lex_string (LEX_STRING lex_str, const char str, size_t length, bool allocate_lex_string)
	Create a LEX_STRING in this connection. More...

bool	convert_string (LEX_STRING to, const CHARSET_INFO to_cs, const char from, size_t from_length, const CHARSET_INFO from_cs)

bool	convert_string (String s, const CHARSET_INFO from_cs, const CHARSET_INFO *to_cs)

int	send_explain_fields (Query_result *result)

void	clear_error ()
	Clear the current error, if any. More...

bool	is_classic_protocol ()

virtual bool	is_connected ()
	Return false if connection to client is broken. More...

void	fatal_error ()
	Mark the current error as fatal. More...

bool	is_error () const
	true if there is an error in the error stack. More...

Diagnostics_area *	get_stmt_da ()
	Returns first Diagnostics Area for the current statement. More...

const Diagnostics_area *	get_stmt_da () const
	Returns first Diagnostics Area for the current statement. More...

const Diagnostics_area *	get_stacked_da () const
	Returns the second Diagnostics Area for the current statement. More...

Diagnostics_area *	get_parser_da ()
	Returns thread-local Diagnostics Area for parsing. More...

Diagnostics_area *	get_query_rewrite_plugin_da ()
	Returns thread-local Diagnostics Area to be used by query rewrite plugins. More...

void	push_diagnostics_area (Diagnostics_area *da, bool copy_conditions=true)
	Push the given Diagnostics Area on top of the stack, making it the new first Diagnostics Area. More...

void	pop_diagnostics_area ()
	Pop the top DA off the Diagnostics Area stack. More...

void	push_protocol (Protocol *protocol)
	Inserts the new protocol at the top of the protocol stack, and make it the current protocol for this thd. More...

void	pop_protocol ()
	Pops the top protocol of the Protocol stack and sets the previous one as the current protocol. More...

const CHARSET_INFO *	charset () const

void	update_charset ()

void	change_item_tree (Item *place, Item new_value)

void	nocheck_register_item_tree_change (Item *place, Item new_value)
	Remember that place was updated with new_value so it can be restored by rollback_item_tree_changes(). More...

void	replace_rollback_place (Item **new_place)
	Find and update change record of an underlying item based on the new value for a place. More...

void	rollback_item_tree_changes ()
	Restore locations set by calls to nocheck_register_item_tree_change(). More...

void	end_statement ()

void	send_kill_message () const

void	reset_n_backup_open_tables_state (Open_tables_backup *backup, uint add_state_flags)

void	restore_backup_open_tables_state (Open_tables_backup *backup)

void	reset_sub_statement_state (Sub_statement_state *backup, uint new_state)

void	restore_sub_statement_state (Sub_statement_state *backup)

void	set_n_backup_active_arena (Query_arena set, Query_arena backup)

void	restore_active_arena (Query_arena set, Query_arena backup)

void	begin_attachable_ro_transaction ()
	Start a read-only attachable transaction. More...

void	begin_attachable_transaction (enum_reset_lex reset_lex)

void	begin_attachable_rw_transaction ()
	Start a read-write attachable transaction. More...

void	begin_attachable_rw_i_s_transaction ()
	Start a read-write attachable transaction to write to mysql.table_stats and mysql.index_stats. More...

void	end_attachable_transaction ()
	End an active attachable transaction. More...

bool	is_attachable_ro_transaction_active () const

bool	is_attachable_transaction_active () const

bool	is_attachable_rw_transaction_active () const

void	set_current_stmt_binlog_format_row_if_mixed ()

void	set_current_stmt_binlog_format_row ()

void	clear_current_stmt_binlog_format_row ()

void	reset_current_stmt_binlog_format_row ()

void	set_original_commit_timestamp_for_slave_thread ()
	Copies variables.original_commit_timestamp to ((Slave_worker *)rli_slave)->original_commit_timestamp, if this is a slave thread. More...

Gtid_set *	get_gtid_next_list ()
	Return the value of @gtid_next_list: either a Gtid_set or NULL. More...

const Gtid_set *	get_gtid_next_list_const () const
	Return the value of @gtid_next_list: either a Gtid_set or NULL. More...

bool	is_binlog_cache_empty (bool is_transactional)
	Return true if the statement/transaction cache is currently empty, false otherwise. More...

void	clear_owned_gtids ()

const LEX_CSTRING &	db () const

bool	set_db (const LEX_CSTRING &new_db)
	Set the current database; use deep copy of C-string. More...

void	reset_db (const LEX_CSTRING &new_db)
	Set the current database; use shallow copy of C-string. More...

bool	copy_db_to (char const *p_db, size_t p_db_length) const

bool	copy_db_to (char *p_db, size_t p_db_length) const

resourcegroups::Resource_group_ctx *	resource_group_ctx ()
	Get resource group context. More...

void	set_psi (PSI_thread *psi)
	Save the performance schema thread instrumentation associated with this user session. More...

PSI_thread *	get_psi ()
	Read the performance schema thread instrumentation associated with this user session. More...

Internal_error_handler *	get_internal_handler ()

void	push_internal_handler (Internal_error_handler *handler)
	Add an internal error handler to the thread execution context. More...

bool	handle_condition (uint sql_errno, const char sqlstate, Sql_condition::enum_severity_level level, const char *msg)
	Handle a sql condition. More...

Internal_error_handler *	pop_internal_handler ()
	Remove the error handler last pushed. More...

void	raise_error (uint code)
	Raise an exception condition. More...

void	raise_error_printf (uint code,...)
	Raise an exception condition, with a formatted message. More...

void	raise_warning (uint code)
	Raise a completion condition (warning). More...

void	raise_warning_printf (uint code,...)
	Raise a completion condition (warning), with a formatted message. More...

void	raise_note (uint code)
	Raise a completion condition (note), with a fixed message. More...

void	raise_note_printf (uint code,...)
	Raise an completion condition (note), with a formatted message. More...

void	set_command (enum enum_server_command command)

enum enum_server_command	get_command () const

void	debug_assert_query_locked () const
	For safe and protected access to the query string, the following rules should be followed: 1: Only the owner (current_thd) can set the query string. More...

const LEX_CSTRING &	query () const

const String	normalized_query ()
	The current query in normalized form. More...

void	set_query (const char *query_arg, size_t query_length_arg)
	Assign a new value to thd->m_query_string. More...

void	set_query (const LEX_CSTRING &query_arg)

void	reset_query ()

void	set_query_id (query_id_t new_query_id)
	Assign a new value to thd->query_id. More...

void	set_open_tables (TABLE *open_tables_arg)
	Assign a new value to open_tables. More...

void	set_is_killable (bool is_killable_arg)
	Assign a new value to is_killable Protected with the LOCK_thd_data mutex. More...

void	enter_locked_tables_mode (enum_locked_tables_mode mode_arg)

void	leave_locked_tables_mode ()
	Leave explicit LOCK TABLES or prelocked mode and restore value of transaction sentinel in MDL subsystem. More...

int	decide_logging_format (TABLE_LIST *tables)
	Decide on logging format to use for the statement and issue errors or warnings as needed. More...

bool	is_dml_gtid_compatible (bool some_transactional_table, bool some_non_transactional_table, bool non_transactional_tables_are_tmp)
	is_dml_gtid_compatible() and is_ddl_gtid_compatible() check if the statement that is about to be processed will safely get a GTID. More...

bool	is_ddl_gtid_compatible ()

void	binlog_invoker ()

bool	need_binlog_invoker ()

void	get_definer (LEX_USER *definer)

void	set_invoker (const LEX_STRING user, const LEX_STRING host)

LEX_CSTRING	get_invoker_user () const

LEX_CSTRING	get_invoker_host () const

bool	has_invoker ()

void	mark_transaction_to_rollback (bool all)
	Mark transaction to rollback and mark error as fatal to a sub-statement. More...

void	init_cost_model ()
	Initialize the optimizer cost model. More...

const Cost_model_server *	cost_model () const
	Retrieve the optimizer cost model for this connection. More...

void	syntax_error ()

void	syntax_error (const char *format,...)
	Push an error message into MySQL diagnostic area with line number and position. More...

void	syntax_error (int mysql_errno,...)
	Push an error message into MySQL diagnostic area with line number and position. More...

void	syntax_error_at (const YYLTYPE &location)

void	syntax_error_at (const YYLTYPE &location, const char *format,...)
	Push a syntax error message into MySQL diagnostic area with line and position information. More...

void	syntax_error_at (const YYLTYPE &location, int mysql_errno,...)
	Push a syntax error message into MySQL diagnostic area with line and position information. More...

void	vsyntax_error_at (const YYLTYPE &location, const char *format, va_list args)

void	vsyntax_error_at (const char pos_in_lexer_raw_buffer, const char format, va_list args)
	Push a syntax error message into MySQL diagnostic area with line number and position. More...

bool	send_result_metadata (List< Item > *list, uint flags)
	Send name and type of result to client. More...

bool	send_result_set_row (List< Item > *row_items)
	Send one result set row. More...

void	send_statement_status ()

void	claim_memory_ownership ()
	Claim all the memory used by the THD object. More...

bool	is_a_srv_session () const

void	mark_as_srv_session ()

uint	get_tmp_table_seq_id ()

void	set_tmp_table_seq_id (uint arg)

bool	is_plugin_fake_ddl () const

void	mark_plugin_fake_ddl (bool flag)

void	set_waiting_for_disk_space (bool waiting)
	Set the waiting_for_disk_space flag. More...

bool	is_waiting_for_disk_space () const
	Returns the current waiting_for_disk_space flag value. More...

bool	sql_parser ()
	Call parser to transform statement into a parse tree. More...


void	set_trans_pos (const char *file, my_off_t pos)
	Functions to set and get transaction position. More...

void	get_trans_pos (const char *file_var, my_off_t pos_var) const

void	get_trans_fixed_pos (const char *file_var, my_off_t pos_var) const

my_off_t	get_trans_pos ()

Public Member Functions inherited from MDL_context_owner
virtual	~MDL_context_owner ()

Public Member Functions inherited from Query_arena
	Query_arena (MEM_ROOT *mem_root_arg, enum enum_state state_arg)

	Query_arena ()

virtual	~Query_arena ()

bool	is_stmt_prepare () const

bool	is_stmt_prepare_or_first_sp_execute () const

bool	is_stmt_prepare_or_first_stmt_execute () const

bool	is_conventional () const

void *	alloc (size_t size)

void *	mem_calloc (size_t size)

template<typename T >
T *	alloc_typed ()

template<typename T >
T *	memdup_typed (const T *mem)

char *	mem_strdup (const char *str)

char *	strmake (const char *str, size_t size) const

void *	memdup (const void *str, size_t size)

void	set_query_arena (const Query_arena *set)
	Copies memory-managing members from `set`. More...

void	free_items ()

virtual void	cleanup_stmt ()

Public Member Functions inherited from Open_tables_state
Reprepare_observer *	get_reprepare_observer () const

void	push_reprepare_observer (Reprepare_observer *o)

Reprepare_observer *	pop_reprepare_observer ()

void	reset_reprepare_observers ()

	Open_tables_state ()
	This constructor initializes Open_tables_state instance which can only be used as backup storage. More...

void	set_open_tables_state (Open_tables_state *state)

void	reset_open_tables_state ()

Static Public Member Functions
static bool	binlog_row_event_extra_data_eq (const uchar a, const uchar b)
	binlog_row_event_extra_data_eq More...

Public Attributes
MDL_context	mdl_context

enum enum_mark_columns	mark_used_columns

ulong	want_privilege
	Used by Item::check_column_privileges() to tell which privileges to check for. More...

LEX *	lex

String	rewritten_query
	In some cases, we may want to modify the query (i.e. More...

Relay_log_info *	rli_fake

Relay_log_info *	rli_slave

NET_SERVER	m_net_server_extension
	Aditional network instrumentation for the server only. More...

collation_unordered_map< std::string, unique_ptr_with_deleter< user_var_entry > >	user_vars {system_charset_info, key_memory_user_var_entry}
	Hash for user variables. More...

String	convert_buffer

struct rand_struct	rand

struct System_variables	variables

struct System_status_var	status_var

struct System_status_var *	initial_status_var

bool	status_var_aggregated

double	m_current_query_cost
	Current query cost. More...

ulonglong	m_current_query_partial_plans
	Current query partial plans. More...

THR_LOCK_INFO	lock_info

mysql_mutex_t	LOCK_thd_data
	Protects THD data accessed from other threads. More...

mysql_mutex_t	LOCK_thd_query
	Protects THD::m_query_string. More...

mysql_mutex_t	LOCK_thd_sysvar
	Protects THD::variables while being updated. More...

mysql_mutex_t	LOCK_thd_protocol
	Protects THD::m_protocol when it gets removed in x plugin. More...

Prepared_statement_map	stmt_map
	All prepared statements of this connection. More...

const char *	thread_stack

Security_context	m_main_security_ctx

Security_context *	m_security_ctx

List< Security_context >	m_view_ctx_list

const char *	proc_info

Protocol_text	protocol_text

Protocol_binary	protocol_binary

class THD::Query_plan	query_plan

const char *	where

ulong	max_client_packet_length

collation_unordered_map< std::string, unique_ptr_my_free< TABLE_LIST > >	handler_tables_hash

malloc_unordered_map< std::string, User_level_lock * >	ull_hash

uint	dbug_sentry

bool	is_killable

mysql_mutex_t	LOCK_current_cond
	Mutex protecting access to current_mutex and current_cond. More...

std::atomic< mysql_mutex_t * >	current_mutex
	The mutex used with current_cond. More...

std::atomic< mysql_cond_t * >	current_cond
	Pointer to the condition variable the thread owning this THD is currently waiting for. More...

mysql_cond_t	COND_thr_lock
	Condition variable used for waiting by the THR_LOCK.c subsystem. More...

uint32	unmasked_server_id

uint32	server_id

uint32	file_id

uint16	peer_port

struct timeval	start_time

struct timeval	user_time

ulonglong	start_utime

ulonglong	utime_after_lock

thr_lock_type	update_lock_default
	Type of lock to be used for all DML statements, except INSERT, in cases when lock is not specified explicitly. More...

thr_lock_type	insert_lock_default
	Type of lock to be used for INSERT statement if lock is not specified explicitly. More...

uint	in_sub_stmt

uint	fill_status_recursion_level
	Used by fill_status() to avoid acquiring LOCK_status mutex twice when this function is called recursively (e.g. More...

uint	fill_variables_recursion_level

rpl_event_coordinates	binlog_next_event_pos

uchar *	binlog_row_event_extra_data

struct THD_timer_info *	timer
	Holds active timer object. More...

struct THD_timer_info *	timer_cache
	After resetting(cancelling) timer, current timer object is cached with timer_cache timer to reuse. More...

Global_read_lock	global_read_lock

Field *	dup_field

Vio *	active_vio = {nullptr}

Item_change_list	change_list

Query_arena *	stmt_arena

table_map	table_map_for_update

bool	arg_of_last_insert_id_function

ulonglong	first_successful_insert_id_in_prev_stmt

ulonglong	first_successful_insert_id_in_prev_stmt_for_binlog

ulonglong	first_successful_insert_id_in_cur_stmt

bool	stmt_depends_on_first_successful_insert_id_in_prev_stmt

Discrete_intervals_list	auto_inc_intervals_in_cur_stmt_for_binlog

Discrete_intervals_list	auto_inc_intervals_forced

ulonglong	previous_found_rows
	Stores the result of the FOUND_ROWS() function. More...

ulonglong	current_found_rows
	Dynamic, collected and set also in subqueries. More...

ulonglong	current_changed_rows
	Number of rows changed in currently executing statement. More...

bool	is_operating_gtid_table_implicitly

bool	is_operating_substatement_implicitly

ha_rows	num_truncated_fields

const CHARSET_INFO *	db_charset

std::unique_ptr< PROFILING >	profiling

PSI_stage_progress *	m_stage_progress_psi
	Current stage progress instrumentation. More...

sql_digest_state *	m_digest
	Current statement digest. More...

unsigned char *	m_token_array
	Current statement digest token array. More...

sql_digest_state	m_digest_state
	Top level statement digest. More...

PSI_statement_locker *	m_statement_psi
	Current statement instrumentation. More...

PSI_statement_locker_state	m_statement_state
	Current statement instrumentation state. More...

PSI_transaction_locker *	m_transaction_psi
	Current transaction instrumentation. More...

PSI_transaction_locker_state	m_transaction_state
	Current transaction instrumentation state. More...

PSI_idle_locker *	m_idle_psi
	Idle instrumentation. More...

PSI_idle_locker_state	m_idle_state
	Idle instrumentation state. More...

bool	m_server_idle
	True if the server code is IDLE for this connection. More...

query_id_t	query_id

ulong	col_access

ulong	statement_id_counter

ulong	rand_saved_seed1

ulong	rand_saved_seed2

my_thread_t	real_id

uint	tmp_table

uint	server_status

uint	open_options

enum enum_thread_type	system_thread

enum_tx_isolation	tx_isolation

bool	tx_read_only

int	tx_priority

int	thd_tx_priority

enum_check_fields	check_for_truncated_fields

Prealloced_array< Binlog_user_var_event *, 2 >	user_var_events

MEM_ROOT *	user_var_events_alloc

THD *	next_to_commit
	Used by MYSQL_BIN_LOG to maintain the commit queue for binary log group commit. More...

bool	binlog_need_explicit_defaults_ts
	The member is served for marking a query that CREATEs or ALTERs a table declared with a TIMESTAMP column as dependent on @session.explicit_defaults_for_timestamp. More...

enum THD::Commit_error	commit_error

enum durability_properties	durability_property

std::atomic< killed_state >	killed

dd::DD_kill_immunizer *	kill_immunizer
	When operation on DD tables is in progress then THD is set to kill immune mode. More...

char	scramble [SCRAMBLE_LENGTH+1]

bool	slave_thread

uchar	password

bool	is_fatal_error
	Set to true if execution of the current compound statement can not continue. More...

bool	transaction_rollback_request
	Set by a storage engine to request the entire transaction (that possibly spans multiple engines) to rollback. More...

bool	is_fatal_sub_stmt_error
	true if we are in a sub-statement and the current error can not be safely recovered until we left the sub-statement mode. More...

bool	query_start_usec_used

bool	rand_used

bool	time_zone_used

bool	substitute_null_with_insert_id

bool	in_lock_tables

bool	is_slave_error
	True if a slave error. More...

bool	thread_specific_used
	is set if some thread specific value(s) used in a statement. More...

bool	charset_is_system_charset
	is set if a statement accesses a temporary table created through CREATE TEMPORARY TABLE. More...

bool	charset_is_collation_connection

bool	charset_is_character_set_filesystem

bool	enable_slow_log

bool	got_warning

bool	derived_tables_processing

bool	parsing_system_view

sp_rcontext *	sp_runtime_ctx
	Current SP-runtime context. More...

sp_cache *	sp_proc_cache

sp_cache *	sp_func_cache

uint	query_name_consts
	number of name_const() substitutions, see sp_head.cc:subst_spvars() More...

LOG_INFO *	current_linfo

union {
bool bool_value

long long_value

ulong ulong_value

ulonglong ulonglong_value

double double_value

}	sys_var_tmp

struct {
bool do_union

bool unioned_events

bool unioned_events_trans

query_id_t first_query_id

}	binlog_evt_union

Parser_state *	m_parser_state
	Internal parser state. More...

Locked_tables_list	locked_tables_list

partition_info *	work_part_info

Plugin_array	audit_class_plugins
	Array of active audit plugins which have been used by this THD. More...

Prealloced_array< unsigned long, 11 >	audit_class_mask
	Array of bits indicating which audit classes have already been added to the list of audit plugins which are currently in use. More...

bool	m_enable_plugins

Gtid	owned_gtid
	The GTID of the currently owned transaction. More...

rpl_sid	owned_sid
	For convenience, this contains the SID component of the GTID stored in owned_gtid. More...

Rpl_thd_context	rpl_thd_ctx

bool	skip_gtid_rollback

bool	is_commit_in_middle_of_statement

bool	has_gtid_consistency_violation

thd_scheduler	scheduler

Opt_trace_context	opt_trace
	optimizer trace of current statement More...

Session_tracker	session_tracker

Session_sysvar_resource_manager	session_sysvar_res_mgr

bool	duplicate_slave_id
	This is only used by master dump threads. More...

XID	debug_binlog_xid_last

Public Attributes inherited from Query_arena
Item *	free_list

MEM_ROOT *	mem_root

bool	is_backup_arena

bool	is_reprepared

enum_state	state

Public Attributes inherited from Open_tables_state
TABLE *	open_tables
	List of regular tables in use by this thread. More...

TABLE *	temporary_tables
	List of temporary tables used by this thread. More...

MYSQL_LOCK *	lock

MYSQL_LOCK *	extra_lock

enum enum_locked_tables_mode	locked_tables_mode

uint	state_flags

Static Public Attributes
static const char *const	DEFAULT_WHERE = "field list"

static const int	OWNED_SIDNO_GTID_SET = -1

static const int	OWNED_SIDNO_ANONYMOUS = -2

Private Member Functions
bool	is_stmt_prepare () const

bool	is_stmt_prepare_or_first_sp_execute () const

bool	is_stmt_prepare_or_first_stmt_execute () const

bool	is_conventional () const

void	cleanup (void)

void	init (void)

Sql_condition *	raise_condition (uint sql_errno, const char sqlstate, Sql_condition::enum_severity_level level, const char msg, bool use_condition_handler=true)
	Raise a generic SQL condition. More...

Private Attributes
std::unique_ptr< LEX >	main_lex
	The lex to hold the parsed tree of conventional (non-prepared) queries. More...

std::unique_ptr< dd::cache::Dictionary_client >	m_dd_client

LEX_CSTRING	m_query_string
	The query associated with this statement. More...

String	m_normalized_query

LEX_CSTRING	m_catalog
	Currently selected catalog. More...

LEX_CSTRING	m_db
	Name of the current (default) database. More...

resourcegroups::Resource_group_ctx	m_resource_group_ctx
	Resource group context indicating the current resource group and the name of the resource group to switch to during execution of a query. More...

mysql_mutex_t	LOCK_query_plan
	Protects query plan (SELECT/UPDATE/DELETE's) from being freed/changed while another thread explains it. More...

Protocol *	m_protocol

SSL_handle	m_SSL = {nullptr}
	SSL data attached to this connection. More...

unsigned int	m_current_stage_key

enum enum_server_command	m_command
	Type of current query: COM_STMT_PREPARE, COM_QUERY, etc. More...

Prealloced_array< Ha_data, PREALLOC_NUM_HA >	ha_data

bool	skip_readonly_check

binlog_filter_state	m_binlog_filter_state
	Indicate if the current statement should be discarded instead of written to the binlog. More...

enum_binlog_format	current_stmt_binlog_format
	Indicates the format in which the current statement will be logged. More...

uint32	binlog_unsafe_warning_flags
	Bit field for the state of binlog warnings. More...

uint	binlog_table_maps

List< char > *	binlog_accessed_db_names

NET	net

String	packet

std::unique_ptr< Transaction_ctx >	m_transaction

Attachable_trx *	m_attachable_trx

longlong	m_row_count_func
	Stores the result of ROW_COUNT() function. More...

ha_rows	m_sent_row_count
	Number of rows we actually sent to the client, including "synthetic" rows in ROLLUP etc. More...

ha_rows	m_examined_row_count
	Number of rows read and/or evaluated for a statement. More...

USER_CONN *	m_user_connect

my_thread_id	m_thread_id
	This counter is 32 bit because of the client protocol. More...

bool	m_release_resources_done

bool	cleanup_done

std::atomic< PSI_thread * >	m_psi
	Performance schema thread instrumentation for this session. More...

Internal_error_handler *	m_internal_handler
	The current internal error handler for this thread, or NULL. More...

MEM_ROOT	main_mem_root
	This memory root is used for two purposes: More...

Diagnostics_area	main_da

Diagnostics_area	m_parser_da
	cf. More...

Diagnostics_area	m_query_rewrite_plugin_da

Diagnostics_area *	m_query_rewrite_plugin_da_ptr

Diagnostics_area *	m_stmt_da

bool	m_binlog_invoker
	It will be set TURE if CURRENT_USER() is called in account management statements or default definer is set in CREATE/ALTER SP, SF, Event, TRIGGER or VIEW statements. More...

LEX_CSTRING	m_invoker_user
	It points to the invoker in the Query_log_event. More...

LEX_CSTRING	m_invoker_host

Cost_model_server	m_cost_model
	Optimizer cost model for server operations. More...

bool	is_a_srv_session_thd
	Variable to mark if the object is part of a Srv_session object, which aggregates THD. More...

bool	m_is_plugin_fake_ddl
	Creating or dropping plugin native table through a plugin service. More...

uint	tmp_table_seq_id
	Sequential number of internal tmp table created in the statement. More...

bool	waiting_for_disk_space = false


const char *	m_trans_log_file
	The binary log position of the transaction. More...

char *	m_trans_fixed_log_file

my_off_t	m_trans_end_pos

Friends
class	Sql_cmd_common_signal

class	Sql_cmd_signal

class	Sql_cmd_resignal

class	Protocol_classic

void	push_warning (THD thd, Sql_condition::enum_severity_level severity, uint code, const char message_text)
	Push the warning to error list if there is still room in the list. More...

void	my_message_sql (uint, const char *, myf)
	All global error messages are sent here where the first one is stored for the client. More...

Detailed Description

For each client connection we create a separate thread with THD serving as a thread/connection descriptor.

Member Enumeration Documentation

◆ binlog_filter_state

enum THD::binlog_filter_state

Enumerator
BINLOG_FILTER_UNKNOWN
BINLOG_FILTER_CLEAR
BINLOG_FILTER_SET

◆ Commit_error

enum THD::Commit_error

Enumerator
CE_NONE
CE_FLUSH_ERROR
CE_SYNC_ERROR
CE_COMMIT_ERROR
CE_ERROR_COUNT

◆ enum_binlog_query_type

enum THD::enum_binlog_query_type

Enumerator
ROW_QUERY_TYPE
STMT_QUERY_TYPE
QUERY_TYPE_COUNT

◆ enum_reset_lex

enum THD::enum_reset_lex

Enumerator
RESET_LEX
DO_NOT_RESET_LEX

◆ killed_state

enum THD::killed_state

Enumerator
NOT_KILLED
KILL_CONNECTION
KILL_QUERY
KILL_TIMEOUT
KILLED_NO_VALUE

Constructor & Destructor Documentation

◆ THD()

THD::THD ( bool enable_plugins = true )

◆ ~THD()

THD::~THD ( )

Member Function Documentation

◆ awake()

void THD::awake ( THD::killed_state state_to_set )

Awake a thread.

Parameters

[in] state_to_set value for THD::killed

This is normally called from another thread's THD object.

Note: Do always call this while holding LOCK_thd_data.

◆ backup_ha_data()

void THD::backup_ha_data ( Prealloced_array< Ha_data, PREALLOC_NUM_HA > * backup )

inline

Copy ha_data into the provided argument.

Used by Attachble_transaction.

◆ begin_attachable_ro_transaction()

void THD::begin_attachable_ro_transaction ( )

Start a read-only attachable transaction.

There must be no active attachable transactions (in other words, there can be only one active attachable transaction at a time).

◆ begin_attachable_rw_i_s_transaction()

void THD::begin_attachable_rw_i_s_transaction ( )

Start a read-write attachable transaction to write to mysql.table_stats and mysql.index_stats.

All the requirements and restrictions to Attachable_trx apply. Additional requirements are documented along the class declaration.

◆ begin_attachable_rw_transaction()

void THD::begin_attachable_rw_transaction ( )

Start a read-write attachable transaction.

All the read-only class' requirements apply. Additional requirements are documented along the class declaration.

◆ begin_attachable_transaction()

void THD::begin_attachable_transaction ( enum_reset_lex reset_lex )

◆ binlog_flush_pending_rows_event()

int THD::binlog_flush_pending_rows_event ( bool stmt_end )

inline

◆ binlog_invoker()

void THD::binlog_invoker ( )

inline

◆ catalog()

const LEX_CSTRING& THD::catalog ( ) const

inline

◆ change_item_tree()

void THD::change_item_tree	(	Item **	place,
		Item *	new_value
	)

◆ charset()

const CHARSET_INFO* THD::charset ( void ) const

inline

◆ claim_memory_ownership()

void THD::claim_memory_ownership ( )

Claim all the memory used by the THD object.

This method is to keep memory instrumentation statistics updated, when an object is transfered across threads.

◆ cleanup()

void THD::cleanup ( void )

private

◆ cleanup_after_query()

void THD::cleanup_after_query ( )

◆ cleanup_connection()

void THD::cleanup_connection ( void )

◆ clear_active_vio()

void THD::clear_active_vio ( )

inline

◆ clear_binlog_local_stmt_filter()

void THD::clear_binlog_local_stmt_filter ( )

inline

◆ clear_binlog_table_maps()

void THD::clear_binlog_table_maps ( )

inline

◆ clear_current_query_costs()

void THD::clear_current_query_costs ( )

inline

Clear the query costs attributes for the current query.

◆ clear_current_stmt_binlog_format_row()

void THD::clear_current_stmt_binlog_format_row ( )

inline

◆ clear_error()

void THD::clear_error ( )

inline

Clear the current error, if any.

We do not clear is_fatal_error or is_fatal_sub_stmt_error since we assume this is never called if the fatal error is set.

◆ clear_next_event_pos()

void THD::clear_next_event_pos ( )

◆ clear_owned_gtids()

void THD::clear_owned_gtids ( )

inline

◆ collation()

const CHARSET_INFO* THD::collation ( )

inline

◆ convert_string() [1/2]

bool THD::convert_string	(	LEX_STRING *	to,
		const CHARSET_INFO *	to_cs,
		const char *	from,
		size_t	from_length,
		const CHARSET_INFO *	from_cs
	)

◆ convert_string() [2/2]

bool THD::convert_string	(	String *	s,
		const CHARSET_INFO *	from_cs,
		const CHARSET_INFO *	to_cs
	)

◆ copy_db_to() [1/2]

bool THD::copy_db_to	(	char const **	p_db,
		size_t *	p_db_length
	)		const

inline

◆ copy_db_to() [2/2]

bool THD::copy_db_to	(	char **	p_db,
		size_t *	p_db_length
	)		const

inline

◆ cost_model()

const Cost_model_server* THD::cost_model ( ) const

inline

Retrieve the optimizer cost model for this connection.

◆ db()

const LEX_CSTRING& THD::db ( ) const

inline

◆ dd_client()

dd::cache::Dictionary_client* THD::dd_client ( ) const

inline

◆ debug_assert_query_locked()

void THD::debug_assert_query_locked ( ) const

For safe and protected access to the query string, the following rules should be followed: 1: Only the owner (current_thd) can set the query string.

This will be protected by LOCK_thd_query. 2: The owner (current_thd) can read the query string without locking LOCK_thd_query. 3: Other threads must lock LOCK_thd_query before reading the query string.

This means that write-write conflicts are avoided by LOCK_thd_query. Read(by owner or other thread)-write(other thread) are disallowed. Read(other thread)-write(by owner) conflicts are avoided by LOCK_thd_query. Read(by owner)-write(by owner) won't happen as THD=thread.

We want to keep current_thd out of header files, so the debug assert, is moved to the .cc file. In optimized mode, we want this getter to be fast, so we inline it.

◆ decrement_user_connections_counter()

void THD::decrement_user_connections_counter ( )

◆ disconnect()

void THD::disconnect ( bool server_shutdown = false )

Disconnect the associated communication endpoint.

Close the Vio associated this session.

Remarks: LOCK_thd_data is taken due to the fact that the Vio might be disassociated concurrently.

◆ end_attachable_transaction()

void THD::end_attachable_transaction ( )

End an active attachable transaction.

Applies to both the read-only and the read-write versions. Note, that the read-write attachable transaction won't be terminated inside this method. To invoke the function there must be active attachable transaction.

◆ end_statement()

void THD::end_statement ( )

◆ enter_cond()

void THD::enter_cond	(	mysql_cond_t *	cond,
		mysql_mutex_t *	mutex,
		const PSI_stage_info *	stage,
		PSI_stage_info *	old_stage,
		const char *	src_function,
		const char *	src_file,
		int	src_line
	)

inlinevirtual

Enter a condition wait.

For enter_cond() / exit_cond() to work the mutex must be held before enter_cond(); this mutex must then be released before exit_cond(). Usage must be: lock mutex; enter_cond(); your code; unlock mutex; exit_cond().

Parameters

	cond	the condition to wait on
	mutex	the associated mutex
[in]	stage	the stage to enter, or NULL
[out]	old_stage	the previous stage, or NULL
	src_function	function name of the caller
	src_file	file name of the caller
	src_line	line number of the caller

See also: ENTER_COND(), THD::enter_cond(); EXIT_COND(), THD::exit_cond()

Implements MDL_context_owner.

◆ enter_locked_tables_mode()

void THD::enter_locked_tables_mode ( enum_locked_tables_mode mode_arg )

inline

◆ enter_stage()

void THD::enter_stage	(	const PSI_stage_info *	stage,
		PSI_stage_info *	old_stage,
		const char *	calling_func,
		const char *	calling_file,
		const unsigned int	calling_line
	)

◆ exit_cond()

void THD::exit_cond	(	const PSI_stage_info *	stage,
		const char *	src_function,
		const char *	src_file,
		int	src_line
	)

inlinevirtual

End a wait on a condition.

Parameters

[in]	stage	the new stage to enter
	src_function	function name of the caller
	src_file	file name of the caller
	src_line	line number of the caller

See also: ENTER_COND(), THD::enter_cond(); EXIT_COND(), THD::exit_cond()

Implements MDL_context_owner.

◆ fatal_error()

void THD::fatal_error ( )

inline

Mark the current error as fatal.

Warning: this does not set any error, it sets a property of the error, so must be followed or prefixed with my_error().

◆ fill_information_schema_tables()

bool THD::fill_information_schema_tables ( )

inline

◆ force_one_auto_inc_interval()

void THD::force_one_auto_inc_interval ( ulonglong next_id )

inline

◆ found_rows()

ulonglong THD::found_rows ( void )

inline

◆ get_binlog_accessed_db_names()

List<char>* THD::get_binlog_accessed_db_names ( )

inline

◆ get_binlog_local_stmt_filter()

binlog_filter_state THD::get_binlog_local_stmt_filter ( )

inline

◆ get_binlog_table_maps()

uint THD::get_binlog_table_maps ( ) const

inline

◆ get_command()

enum enum_server_command THD::get_command ( ) const

inline

◆ get_definer()

void THD::get_definer ( LEX_USER * definer )

◆ get_examined_row_count()

ha_rows THD::get_examined_row_count ( ) const

inline

◆ get_gtid_next_list()

Gtid_set* THD::get_gtid_next_list ( )

inline

Return the value of @gtid_next_list: either a Gtid_set or NULL.

◆ get_gtid_next_list_const()

const Gtid_set* THD::get_gtid_next_list_const ( ) const

inline

Return the value of @gtid_next_list: either a Gtid_set or NULL.

◆ get_ha_data()

Ha_data* THD::get_ha_data ( int slot )

inline

Retrieve Ha_data for a given slot.

Each handler has a fixed slot nr.

◆ get_internal_handler()

Internal_error_handler* THD::get_internal_handler ( )

inline

◆ get_invoker_host()

LEX_CSTRING THD::get_invoker_host ( ) const

inline

◆ get_invoker_user()

LEX_CSTRING THD::get_invoker_user ( ) const

inline

◆ get_parser_da()

Diagnostics_area* THD::get_parser_da ( )

inline

Returns thread-local Diagnostics Area for parsing.

We need to have a clean DA in case errors or warnings are thrown during parsing, but we can't just reset the main DA in case we have a diagnostic statement on our hand that needs the old DA to answer questions about the previous execution. Keeping a static per-thread DA for parsing is less costly than allocating a temporary one for each statement we parse.

◆ get_proc_info()

const char* THD::get_proc_info ( ) const

inline

◆ get_protocol()

Protocol* THD::get_protocol ( )

inline

◆ get_protocol_classic()

Protocol_classic* THD::get_protocol_classic ( ) const

inline

Asserts that the protocol is of type text or binary and then returns the m_protocol casted to Protocol_classic.

This method is needed to prevent misuse of pluggable protocols by legacy code

◆ get_psi()

PSI_thread* THD::get_psi ( )

inline

Read the performance schema thread instrumentation associated with this user session.

This method is safe to use from a different thread.

◆ get_query_rewrite_plugin_da()

Diagnostics_area* THD::get_query_rewrite_plugin_da ( )

inline

Returns thread-local Diagnostics Area to be used by query rewrite plugins.

Query rewrite plugins use their own diagnostics area. The reason is that they are invoked right before and right after parsing, and we don't want conditions raised by plugins in either statement nor parser DA until we know which type of statement we have parsed.

Note: The diagnostics area is instantiated the first time it is asked for.

◆ get_rand_seed()

virtual uint THD::get_rand_seed ( )

inlinevirtual

Provide thread specific random seed for MDL_context's PRNG.

Note that even if two connections will request seed during handling of statements which were started at exactly the same time, and thus will get the same values in PRNG at the start, they will naturally diverge soon, since calls to PRNG in MDL subsystem are affected by many factors making process quite random. OTOH the fact that we use time as a seed gives more randomness and thus better coverage in tests as opposed to using thread_id for the same purpose.

Implements MDL_context_owner.

◆ get_row_count_func()

longlong THD::get_row_count_func ( ) const

inline

◆ get_sent_row_count()

ha_rows THD::get_sent_row_count ( ) const

inline

◆ get_ssl()

SSL_handle THD::get_ssl ( ) const

inline

◆ get_stacked_da()

const Diagnostics_area* THD::get_stacked_da ( ) const

inline

Returns the second Diagnostics Area for the current statement.

◆ get_stmt_da() [1/2]

Diagnostics_area* THD::get_stmt_da ( )

inline

Returns first Diagnostics Area for the current statement.

◆ get_stmt_da() [2/2]

const Diagnostics_area* THD::get_stmt_da ( ) const

inline

Returns first Diagnostics Area for the current statement.

◆ get_thd()

virtual THD* THD::get_thd ( )

inlinevirtual

Within MDL subsystem this one is only used for DEBUG_SYNC.

Do not use it to peek/poke into other parts of THD from MDL. However it is OK to use this method in callbacks provided by SQL-layer to MDL subsystem (since SQL-layer has full access to THD anyway).

Implements MDL_context_owner.

◆ get_tmp_table_seq_id()

uint THD::get_tmp_table_seq_id ( )

inline

◆ get_trans_fixed_pos()

void THD::get_trans_fixed_pos	(	const char **	file_var,
		my_off_t *	pos_var
	)		const

inline

◆ get_trans_pos() [1/2]

void THD::get_trans_pos	(	const char **	file_var,
		my_off_t *	pos_var
	)		const

inline

◆ get_trans_pos() [2/2]

my_off_t THD::get_trans_pos ( )

inline

◆ get_transaction() [1/2]

Transaction_ctx* THD::get_transaction ( )

inline

◆ get_transaction() [2/2]

const Transaction_ctx* THD::get_transaction ( ) const

inline

◆ get_user_connect()

const USER_CONN* THD::get_user_connect ( )

inline

◆ get_vio_type()

enum_vio_type THD::get_vio_type ( )

◆ handle_condition()

bool THD::handle_condition	(	uint	sql_errno,
		const char *	sqlstate,
		Sql_condition::enum_severity_level *	level,
		const char *	msg
	)

Handle a sql condition.

Parameters

sql_errno	the condition error number
sqlstate	the condition sqlstate
level	the condition level
msg	the condition message text

Returns: true if the condition is handled

◆ has_invoker()

bool THD::has_invoker ( )

inline

◆ in_active_multi_stmt_transaction()

bool THD::in_active_multi_stmt_transaction ( ) const

inline

true if the session is in a multi-statement transaction mode (

See also: in_multi_stmt_transaction_mode()) and there is an active transaction, i.e. there is an explicit start of a transaction with BEGIN statement, or implicit with a statement that uses a transactional engine.

For example, these scenarios don't start an active transaction (even though the server is in multi-statement transaction mode):

set @@autocommit=0;
select * from nontrans_table;
set @var = true;
flush tables;

Note, that even for a statement that starts a multi-statement transaction (i.e. select * from trans_table), this flag won't be set until we open the statement's tables and the engines register themselves for the transaction (see trans_register_ha()), hence this method is reliable to use only after open_tables() has completed.

Why do we need a flag?

We need to maintain a (at first glance redundant) session flag, rather than looking at thd->transaction.all.ha_list because of explicit start of a transaction with BEGIN.

I.e. in case of BEGIN; select * from nontrans_t1; <– in_active_multi_stmt_transaction() is true

◆ in_multi_stmt_transaction_mode()

bool THD::in_multi_stmt_transaction_mode ( ) const

inline

Returns true if session is in a multi-statement transaction mode.

OPTION_NOT_AUTOCOMMIT: When autocommit is off, a multi-statement transaction is implicitly started on the first statement after a previous transaction has been ended.

OPTION_BEGIN: Regardless of the autocommit status, a multi-statement transaction can be explicitly started with the statements "START TRANSACTION", "BEGIN [WORK]", "[COMMIT | ROLLBACK] AND CHAIN", etc.

Note: this doesn't tell you whether a transaction is active. A session can be in multi-statement transaction mode, and yet have no active transaction, e.g., in case of: set @@autocommit=0; set @a= 3; <– these statements don't set transaction isolation level serializable; <– start an active flush tables; <– transaction

I.e. for the above scenario this function returns true, even though no active transaction has begun.

See also: in_active_multi_stmt_transaction()

◆ inc_examined_row_count()

void THD::inc_examined_row_count ( ha_rows count )

◆ inc_sent_row_count()

void THD::inc_sent_row_count ( ha_rows count )

◆ inc_status_created_tmp_disk_tables()

void THD::inc_status_created_tmp_disk_tables ( )

◆ inc_status_created_tmp_tables()

void THD::inc_status_created_tmp_tables ( )

◆ inc_status_select_full_join()

void THD::inc_status_select_full_join ( )

◆ inc_status_select_full_range_join()

void THD::inc_status_select_full_range_join ( )

◆ inc_status_select_range()

void THD::inc_status_select_range ( )

◆ inc_status_select_range_check()

void THD::inc_status_select_range_check ( )

◆ inc_status_select_scan()

void THD::inc_status_select_scan ( )

◆ inc_status_sort_merge_passes()

void THD::inc_status_sort_merge_passes ( )

◆ inc_status_sort_range()

void THD::inc_status_sort_range ( )

◆ inc_status_sort_rows()

void THD::inc_status_sort_rows ( ha_rows count )

◆ inc_status_sort_scan()

void THD::inc_status_sort_scan ( )

◆ increment_con_per_hour_counter()

void THD::increment_con_per_hour_counter ( )

◆ increment_questions_counter()

void THD::increment_questions_counter ( )

◆ increment_updates_counter()

void THD::increment_updates_counter ( )

◆ increment_user_connections_counter()

void THD::increment_user_connections_counter ( )

◆ init()

void THD::init ( void )

private

◆ init_cost_model()

void THD::init_cost_model ( )

inline

Initialize the optimizer cost model.

This function should be called each time a new query is started.

◆ init_query_mem_roots()

void THD::init_query_mem_roots ( )

Initialize memory roots necessary for query processing and (!) pre-allocate memory for it.

We can't do that in THD constructor because there are use cases (acl_init, watcher threads, killing mysqld) where it's vital to not allocate excessive and not used memory. Note, that we still don't return error from init_query_mem_roots() if preallocation fails, we should notice that at the first call to alloc_root.

◆ is_a_srv_session()

bool THD::is_a_srv_session ( ) const

inline

◆ is_attachable_ro_transaction_active()

bool THD::is_attachable_ro_transaction_active ( ) const

inline

Returns: true if there is an active attachable transaction.

◆ is_attachable_rw_transaction_active()

bool THD::is_attachable_rw_transaction_active ( ) const

Returns: true if there is an active rw attachable transaction.

◆ is_attachable_transaction_active()

bool THD::is_attachable_transaction_active ( ) const

inline

Returns: true if there is an active attachable transaction.

◆ is_binlog_applier()

bool THD::is_binlog_applier ( )

inline

The function checks whether the thread is processing queries from binlog, as automatically generated by mysqlbinlog.

Returns: true when the thread is a binlog applier

◆ is_bootstrap_system_thread()

bool THD::is_bootstrap_system_thread ( ) const

inline

◆ is_classic_protocol()

bool THD::is_classic_protocol ( )

inline

◆ is_cmd_skip_readonly()

bool THD::is_cmd_skip_readonly ( )

inline

◆ is_connected()

virtual bool THD::is_connected ( )

inlinevirtual

Return false if connection to client is broken.

Implements MDL_context_owner.

◆ is_conventional()

bool THD::is_conventional ( ) const

inlineprivate

◆ is_current_stmt_binlog_disabled()

bool THD::is_current_stmt_binlog_disabled ( ) const

Determine if binlogging is disabled for this session.

Return values

0	if the current statement binlogging is disabled (could be because of binlog closed/binlog option is set to false).
1	if the current statement will be binlogged

◆ is_current_stmt_binlog_format_row()

int THD::is_current_stmt_binlog_format_row ( ) const

inline

Determine the binlog format of the current statement.

Return values

0	if the current statement will be logged in statement format.
nonzero	if the current statement will be logged in row format.

◆ is_current_stmt_binlog_row_enabled_with_write_set_extraction()

bool THD::is_current_stmt_binlog_row_enabled_with_write_set_extraction ( ) const

Determine if binloging is enabled in row format and write set extraction is enabled for this session.

Return values

true	if is enable
false	otherwise

◆ is_dd_system_thread()

bool THD::is_dd_system_thread ( ) const

inline

◆ is_error()

bool THD::is_error ( ) const

inline

true if there is an error in the error stack.

Please use this method instead of direct access to net.report_error.

If true, the current (sub)-statement should be aborted. The main difference between this member and is_fatal_error is that a fatal error can not be handled by a stored procedure continue handler, whereas a normal error can.

To raise this flag, use my_error().

◆ is_fsp_truncate_mode()

bool THD::is_fsp_truncate_mode ( ) const

inline

◆ is_initialize_system_thread()

bool THD::is_initialize_system_thread ( ) const

inline

◆ is_killed()

virtual int THD::is_killed ( ) const

inlinefinalvirtual

Has the owner thread been killed?

Implements MDL_context_owner.

◆ is_plugin_fake_ddl()

bool THD::is_plugin_fake_ddl ( ) const

inline

◆ is_stmt_prepare()

bool THD::is_stmt_prepare ( ) const

inlineprivate

◆ is_stmt_prepare_or_first_sp_execute()

bool THD::is_stmt_prepare_or_first_sp_execute ( ) const

inlineprivate

◆ is_stmt_prepare_or_first_stmt_execute()

bool THD::is_stmt_prepare_or_first_stmt_execute ( ) const

inlineprivate

◆ is_strict_mode()

bool THD::is_strict_mode ( ) const

inline

◆ is_system_thread()

bool THD::is_system_thread ( ) const

inline

◆ is_waiting_for_disk_space()

bool THD::is_waiting_for_disk_space ( ) const

inline

Returns the current waiting_for_disk_space flag value.

◆ leave_locked_tables_mode()

void THD::leave_locked_tables_mode ( )

Leave explicit LOCK TABLES or prelocked mode and restore value of transaction sentinel in MDL subsystem.

◆ lock_query_plan()

void THD::lock_query_plan ( )

inline

Locks the query plan of this THD.

◆ make_lex_string() [1/2]

LEX_CSTRING * THD::make_lex_string	(	LEX_CSTRING *	lex_str,
		const char *	str,
		size_t	length,
		bool	allocate_lex_string
	)

◆ make_lex_string() [2/2]

LEX_STRING * THD::make_lex_string	(	LEX_STRING *	lex_str,
		const char *	str,
		size_t	length,
		bool	allocate_lex_string
	)

Create a LEX_STRING in this connection.

Parameters

lex_str	pointer to LEX_STRING object to be initialized
str	initializer to be copied into lex_str
length	length of str, in bytes
allocate_lex_string	if true, allocate new LEX_STRING object, instead of using lex_str value

Returns: NULL on failure, or pointer to the LEX_STRING object

◆ mark_as_srv_session()

void THD::mark_as_srv_session ( )

inline

◆ mark_plugin_fake_ddl()

void THD::mark_plugin_fake_ddl ( bool flag )

inline

◆ mark_transaction_to_rollback()

void THD::mark_transaction_to_rollback ( bool all )

Mark transaction to rollback and mark error as fatal to a sub-statement.

Parameters

all	true <=> rollback main transaction.

◆ need_binlog_invoker()

bool THD::need_binlog_invoker ( )

inline

◆ nocheck_register_item_tree_change()

void THD::nocheck_register_item_tree_change	(	Item **	place,
		Item *	new_value
	)

Remember that place was updated with new_value so it can be restored by rollback_item_tree_changes().

Parameters

[in]	place	the location that will change, and whose old value we need to remember for restoration
[in]	new_value	new value about to be inserted into *place, remember for associative lookup, see replace_rollback_place()

◆ normalized_query()

const String THD::normalized_query ( )

The current query in normalized form.

The format is intended to be identical to the digest text of performance_schema, but not limited in size. In this case the parse tree is traversed as opposed to a (limited) token buffer. The string is allocated by this Statement and will be available until the next call to this function or this object is deleted.

Note: We have no protection against out-of-memory errors as this function relies on the Item::print() interface which does not propagate errors.

Returns: The current query in normalized form.

◆ notify_hton_post_release_exclusive()

void THD::notify_hton_post_release_exclusive ( const MDL_key * mdl_key )

virtual

Notify interested storage engines that we have just released exclusive lock for the key.

Implements MDL_context_owner.

◆ notify_hton_pre_acquire_exclusive()

bool THD::notify_hton_pre_acquire_exclusive	(	const MDL_key *	mdl_key,
		bool *	victimized
	)

virtual

Notify/get permission from interested storage engines before acquiring exclusive lock for the key.

The returned argument 'victimized' specify reason for lock not granted. If 'true', lock was refused in an attempt to resolve a possible MDL->GSL deadlock. Locking may then be retried.

Returns: False if notification was successful and it is OK to acquire lock, True if one of SEs asks to abort lock acquisition.

Implements MDL_context_owner.

◆ notify_shared_lock()

void THD::notify_shared_lock	(	MDL_context_owner *	ctx_in_use,
		bool	needs_thr_lock_abort
	)

virtual

A callback to the server internals that is used to address special cases of the locking protocol.

Invoked when acquiring an exclusive lock, for each thread that has a conflicting shared metadata lock.

This function aborts waiting of the thread on a data lock, to make it notice the pending exclusive lock and back off.

Note: This function does not wait for the thread to give away its locks. Waiting is done outside for all threads at once.

Parameters

ctx_in_use	The MDL context owner (thread) to wake up.
needs_thr_lock_abort	Indicates that to wake up thread this call needs to abort its waiting on table-level lock.

Implements MDL_context_owner.

◆ optimizer_switch_flag()

bool THD::optimizer_switch_flag ( ulonglong flag ) const

inline

Tells whether the given optimizer_switch flag is on.

◆ pop_diagnostics_area()

void THD::pop_diagnostics_area ( )

inline

Pop the top DA off the Diagnostics Area stack.

◆ pop_internal_handler()

Internal_error_handler * THD::pop_internal_handler ( )

Remove the error handler last pushed.

◆ pop_protocol()

void THD::pop_protocol ( )

inline

Pops the top protocol of the Protocol stack and sets the previous one as the current protocol.

◆ push_diagnostics_area()

void THD::push_diagnostics_area	(	Diagnostics_area *	da,
		bool	copy_conditions = `true`
	)

inline

Push the given Diagnostics Area on top of the stack, making it the new first Diagnostics Area.

Conditions in the new second Diagnostics Area will be copied to the new first Diagnostics Area.

Parameters

da	Diagnostics Area to be come the top of the Diagnostics Area stack.
copy_conditions	Copy the conditions from the new second Diagnostics Area to the new first Diagnostics Area, as per SQL standard.

◆ push_internal_handler()

void THD::push_internal_handler ( Internal_error_handler * handler )

Add an internal error handler to the thread execution context.

Parameters

handler the exception handler to add

◆ push_protocol()

void THD::push_protocol ( Protocol * protocol )

inline

Inserts the new protocol at the top of the protocol stack, and make it the current protocol for this thd.

Parameters

protocol Protocol to be inserted.

◆ query()

const LEX_CSTRING& THD::query ( ) const

inline

◆ query_start_in_secs()

time_t THD::query_start_in_secs ( ) const

inline

◆ query_start_timeval_trunc()

struct timeval THD::query_start_timeval_trunc ( uint decimals )

◆ raise_condition()

Sql_condition * THD::raise_condition	(	uint	sql_errno,
		const char *	sqlstate,
		Sql_condition::enum_severity_level	level,
		const char *	msg,
		bool	use_condition_handler = `true`
	)

private

Raise a generic SQL condition.

Parameters

sql_errno	the condition error number
sqlstate	the condition SQLSTATE
level	the condition level
msg	the condition message text
use_condition_handler	Invoke the handle_condition.

Returns: The condition raised, or NULL

◆ raise_error()

void THD::raise_error ( uint code )

Raise an exception condition.

Parameters

code	the MYSQL_ERRNO error code of the error

◆ raise_error_printf()

void THD::raise_error_printf	(	uint	code,
			...
	)

Raise an exception condition, with a formatted message.

Parameters

code	the MYSQL_ERRNO error code of the error

◆ raise_note()

void THD::raise_note ( uint code )

Raise a completion condition (note), with a fixed message.

Parameters

code	the MYSQL_ERRNO error code of the note

◆ raise_note_printf()

void THD::raise_note_printf	(	uint	code,
			...
	)

Raise an completion condition (note), with a formatted message.

Parameters

code	the MYSQL_ERRNO error code of the note

◆ raise_warning()

void THD::raise_warning ( uint code )

Raise a completion condition (warning).

Parameters

code	the MYSQL_ERRNO error code of the warning

◆ raise_warning_printf()

void THD::raise_warning_printf	(	uint	code,
			...
	)

Raise a completion condition (warning), with a formatted message.

Parameters

code	the MYSQL_ERRNO error code of the warning

◆ read_first_successful_insert_id_in_prev_stmt()

ulonglong THD::read_first_successful_insert_id_in_prev_stmt ( void )

inline

◆ record_first_successful_insert_id_in_cur_stmt()

void THD::record_first_successful_insert_id_in_cur_stmt ( ulonglong id_arg )

inline

◆ release_resources()

void THD::release_resources ( )

Release most resources, prior to THD destruction.

◆ release_resources_done()

bool THD::release_resources_done ( ) const

inline

◆ replace_rollback_place()

void THD::replace_rollback_place ( Item ** new_place )

Find and update change record of an underlying item based on the new value for a place.

If we have already saved a position to rollback for new_value, forget that rollback position and register the new place instead, typically because a transformation has made the old place irrelevant. If not, a no-op.

Parameters

new_place The new location in which we have presumably saved the new value, but which need to be rolled back to the old value. This location must also contain the new value.

◆ reset_binlog_local_stmt_filter()

void THD::reset_binlog_local_stmt_filter ( )

inline

◆ reset_current_stmt_binlog_format_row()

void THD::reset_current_stmt_binlog_format_row ( )

inline

◆ reset_db()

void THD::reset_db ( const LEX_CSTRING & new_db )

inline

Set the current database; use shallow copy of C-string.

Parameters

new_db the new database name.

Note: This operation just sets {db, db_length}. Switching the current database usually involves other actions, like switching other database attributes including security context. In the future, this operation will be made private and more convenient interface will be provided.

◆ reset_first_successful_insert_id()

void THD::reset_first_successful_insert_id ( )

inline

◆ reset_n_backup_open_tables_state()

void THD::reset_n_backup_open_tables_state	(	Open_tables_backup *	backup,
		uint	add_state_flags
	)

◆ reset_query()

void THD::reset_query ( )

inline

◆ reset_skip_readonly_check()

void THD::reset_skip_readonly_check ( )

inline

◆ reset_sub_statement_state()

void THD::reset_sub_statement_state	(	Sub_statement_state *	backup,
		uint	new_state
	)

◆ resource_group_ctx()

resourcegroups::Resource_group_ctx* THD::resource_group_ctx ( )

inline

Get resource group context.

Returns: pointer to resource group context.

◆ restore_active_arena()

void THD::restore_active_arena	(	Query_arena *	set,
		Query_arena *	backup
	)

◆ restore_backup_open_tables_state()

void THD::restore_backup_open_tables_state ( Open_tables_backup * backup )

◆ restore_globals()

void THD::restore_globals ( )

◆ restore_ha_data()

void THD::restore_ha_data ( const Prealloced_array< Ha_data, PREALLOC_NUM_HA > & backup )

inline

Restore ha_data from the provided backup copy.

Used by Attachable_Transaction.

◆ restore_sub_statement_state()

void THD::restore_sub_statement_state ( Sub_statement_state * backup )

◆ rollback_item_tree_changes()

void THD::rollback_item_tree_changes ( )

Restore locations set by calls to nocheck_register_item_tree_change().

The value to be restored depends on whether replace_rollback_place() has been called. If not, we restore the original value. If it has been called, we restore the one supplied by the latest call to replace_rollback_place()

◆ rpl_detach_engine_ha_data()

void THD::rpl_detach_engine_ha_data ( )

When the thread is a binlog or slave applier it detaches the engine ha_data associated with it and memorizes the fact of that.

◆ rpl_reattach_engine_ha_data()

void THD::rpl_reattach_engine_ha_data ( )

When the thread is a binlog or slave applier it reattaches the engine ha_data associated with it and memorizes the fact of that.

◆ rpl_unflag_detached_engine_ha_data()

bool THD::rpl_unflag_detached_engine_ha_data ( )

Returns: true when the current binlog (rli_fake) or slave (rli_slave) applier thread has detached the engine ha_data, see rpl_detach_engine_ha_data.

Note: The detached transaction applier resets a memo mark at once with this check.

◆ save_current_query_costs()

void THD::save_current_query_costs ( )

inline

Save the current query costs attributes in the thread session status.

Use this method only after the query execution is completed, so that

SHOW SESSION STATUS like 'last_query_%'

SELECT * from performance_schema.session_status

WHERE VARIABLE_NAME like 'last_query_%'

actually reports the previous query, not itself.

◆ security_context()

Security_context* THD::security_context ( ) const

inline

◆ send_explain_fields()

int THD::send_explain_fields ( Query_result * result )

◆ send_kill_message()

void THD::send_kill_message ( ) const

◆ send_result_metadata()

bool THD::send_result_metadata	(	List< Item > *	list,
		uint	flags
	)

Send name and type of result to client.

Sum fields has table name empty and field_name.

Parameters

list	List of items to send to client
flags	Bit mask with the following functions: 1 send number of rows 2 send default values 4 don't write eof packet

Return values

false	ok
true	Error (Note that in this case the error is not sent to the client)

◆ send_result_set_row()

bool THD::send_result_set_row ( List< Item > * row_items )

Send one result set row.

Parameters

row_items a collection of column values for that row

Returns: Error status.

Return values

true	Error.
false	Success.

◆ send_statement_status()

void THD::send_statement_status ( )

◆ set_active_vio()

void THD::set_active_vio ( Vio * vio )

inline

◆ set_binlog_local_stmt_filter()

void THD::set_binlog_local_stmt_filter ( )

inline

◆ set_catalog()

void THD::set_catalog ( const LEX_CSTRING & catalog )

inline

◆ set_command()

void THD::set_command ( enum enum_server_command command )

◆ set_current_stmt_binlog_format_row()

void THD::set_current_stmt_binlog_format_row ( )

inline

◆ set_current_stmt_binlog_format_row_if_mixed()

void THD::set_current_stmt_binlog_format_row_if_mixed ( )

inline

◆ set_db()

bool THD::set_db ( const LEX_CSTRING & new_db )

Set the current database; use deep copy of C-string.

Parameters

new_db the new database name.

Initialize the current database from a NULL-terminated string with length. If we run out of memory, we free the current database and return true. This way the user will notice the error as there will be no current database selected (in addition to the error message set by malloc).

Note: This operation just sets {db, db_length}. Switching the current database usually involves other actions, like switching other database attributes including security context. In the future, this operation will be made private and more convenient interface will be provided.

Returns: Operation status

Return values

false	Success
true	Out-of-memory error

◆ set_invoker()

void THD::set_invoker	(	const LEX_STRING *	user,
		const LEX_STRING *	host
	)

inline

◆ set_is_killable()

void THD::set_is_killable ( bool is_killable_arg )

inline

Assign a new value to is_killable Protected with the LOCK_thd_data mutex.

◆ set_n_backup_active_arena()

void THD::set_n_backup_active_arena	(	Query_arena *	set,
		Query_arena *	backup
	)

◆ set_new_thread_id()

void THD::set_new_thread_id ( )

Assign a value to m_thread_id by calling Global_THD_manager::get_new_thread_id().

◆ set_next_event_pos()

void THD::set_next_event_pos	(	const char *	_filename,
		ulonglong	_pos
	)

◆ set_open_tables()

void THD::set_open_tables ( TABLE * open_tables_arg )

inline

Assign a new value to open_tables.

Protected with the LOCK_thd_data mutex.

◆ set_original_commit_timestamp_for_slave_thread()

void THD::set_original_commit_timestamp_for_slave_thread ( )

Copies variables.original_commit_timestamp to ((Slave_worker *)rli_slave)->original_commit_timestamp, if this is a slave thread.

◆ set_psi()

void THD::set_psi ( PSI_thread * psi )

inline

Save the performance schema thread instrumentation associated with this user session.

Parameters

psi	Performance schema thread instrumentation

◆ set_query() [1/2]

void THD::set_query	(	const char *	query_arg,
		size_t	query_length_arg
	)

inline

Assign a new value to thd->m_query_string.

Protected with the LOCK_thd_query mutex.

◆ set_query() [2/2]

void THD::set_query ( const LEX_CSTRING & query_arg )

◆ set_query_id()

void THD::set_query_id ( query_id_t new_query_id )

inline

Assign a new value to thd->query_id.

Protected with the LOCK_thd_data mutex.

◆ set_row_count_func()

void THD::set_row_count_func ( longlong row_count_func )

inline

◆ set_security_context()

void THD::set_security_context ( Security_context * sctx )

inline

◆ set_sent_row_count()

void THD::set_sent_row_count ( ha_rows count )

◆ set_server_id()

void THD::set_server_id ( uint32 sid )

inline

◆ set_skip_readonly_check()

void THD::set_skip_readonly_check ( )

inline

◆ set_ssl()

void THD::set_ssl ( Vio * vio )

inline

◆ set_status_no_good_index_used()

void THD::set_status_no_good_index_used ( )

◆ set_status_no_index_used()

void THD::set_status_no_index_used ( )

◆ set_time() [1/2]

void THD::set_time ( )

inline

◆ set_time() [2/2]

void THD::set_time ( const struct timeval * t )

inline

◆ set_time_after_lock()

void THD::set_time_after_lock ( )

inline

◆ set_tmp_table_seq_id()

void THD::set_tmp_table_seq_id ( uint arg )

inline

◆ set_trans_pos()

void THD::set_trans_pos	(	const char *	file,
		my_off_t	pos
	)

inline

Functions to set and get transaction position.

These functions are used to set the transaction position for the transaction written when committing this transaction.

◆ set_transaction()

void THD::set_transaction ( Transaction_ctx * transaction_ctx )

Changes the Transaction_ctx instance within THD-object.

The previous Transaction_ctx instance is destroyed.

Note: this is a THD-internal operation which MUST NOT be used outside.

Parameters

transaction_ctx new Transaction_ctx instance to be associated with the THD-object.

◆ set_user_connect()

void THD::set_user_connect ( USER_CONN * uc )

◆ set_waiting_for_disk_space()

void THD::set_waiting_for_disk_space ( bool waiting )

inline

Set the waiting_for_disk_space flag.

Parameters

waiting The value to set in the flag.

◆ shutdown_active_vio()

void THD::shutdown_active_vio ( )

◆ sql_parser()

bool THD::sql_parser ( )

Call parser to transform statement into a parse tree.

Then, transform the parse tree further into an AST, ready for resolving.

◆ store_globals()

bool THD::store_globals ( )

◆ syntax_error() [1/3]

void THD::syntax_error ( )

inline

◆ syntax_error() [2/3]

void THD::syntax_error	(	const char *	format,
			...
	)

Push an error message into MySQL diagnostic area with line number and position.

This function provides semantic action implementers with a way to push the famous "You have a syntax error near..." error message into the diagnostic area, which is normally produced only if a syntax error is discovered according to the Bison grammar. Unlike the syntax_error_at() function, the error position points to the last parsed token.

Note: Parse-time only function!

Parameters

format Error format message. NULL means ER(ER_SYNTAX_ERROR).

◆ syntax_error() [3/3]

void THD::syntax_error	(	int	mysql_errno,
			...
	)

Push an error message into MySQL diagnostic area with line number and position.

This function provides semantic action implementers with a way to push the famous "You have a syntax error near..." error message into the diagnostic area, which is normally produced only if a syntax error is discovered according to the Bison grammar. Unlike the syntax_error_at() function, the error position points to the last parsed token.

Note: Parse-time only function!

Parameters

mysql_errno Error number to get a format string with ER_THD().

◆ syntax_error_at() [1/3]

void THD::syntax_error_at ( const YYLTYPE & location )

inline

◆ syntax_error_at() [2/3]

void THD::syntax_error_at	(	const YYLTYPE &	location,
		const char *	format,
			...
	)

Push a syntax error message into MySQL diagnostic area with line and position information.

This function provides semantic action implementers with a way to push the famous "You have a syntax error near..." error message into the diagnostic area, which is normally produced only if a parse error is discovered internally by the Bison generated parser.

Note: Parse-time only function!

Parameters

location	YYSTYPE object: error position.
format	Error format message. NULL means ER(ER_SYNTAX_ERROR).

◆ syntax_error_at() [3/3]

void THD::syntax_error_at	(	const YYLTYPE &	location,
		int	mysql_errno,
			...
	)

Push a syntax error message into MySQL diagnostic area with line and position information.

This function provides semantic action implementers with a way to push the famous "You have a syntax error near..." error message into the diagnostic area, which is normally produced only if a parse error is discovered internally by the Bison generated parser.

Note: Parse-time only function!

Parameters

location	YYSTYPE object: error position
mysql_errno	Error number to get a format string with ER_THD()

◆ thread_id()

my_thread_id THD::thread_id ( ) const

inline

◆ time_out_user_resource_limits()

void THD::time_out_user_resource_limits ( )

◆ time_zone()

Time_zone* THD::time_zone ( )

inline

◆ unlock_query_plan()

void THD::unlock_query_plan ( )

inline

◆ update_charset()

void THD::update_charset ( )

◆ update_previous_found_rows()

void THD::update_previous_found_rows ( )

inline

◆ update_slow_query_status()

void THD::update_slow_query_status ( )

inline

Evaluate the current time, and if it exceeds the long-query-time setting, mark the query as slow.

◆ vsyntax_error_at() [1/2]

void THD::vsyntax_error_at	(	const YYLTYPE &	location,
		const char *	format,
		va_list	args
	)

inline

◆ vsyntax_error_at() [2/2]

void THD::vsyntax_error_at	(	const char *	pos_in_lexer_raw_buffer,
		const char *	format,
		va_list	args
	)

Push a syntax error message into MySQL diagnostic area with line number and position.

This function provides semantic action implementers with a way to push the famous "You have a syntax error near..." error message into the error stack, which is normally produced only if a parse error is discovered internally by the Bison generated parser.

Parameters

pos_in_lexer_raw_buffer	Pointer into LEX::m_buf or NULL.
format	An error message format string.
args	Arguments to the format string.

Friends And Related Function Documentation

◆ my_message_sql

void my_message_sql	(	uint	,
		const char *	,
		myf
	)

friend

All global error messages are sent here where the first one is stored for the client.

Reporting an error invokes audit API call that notifies the error to the plugin. Audit API that generate the error adds a protection (condition handler) that prevents entering infinite recursion, when a plugin signals error, when already handling the error.

handle_condition is normally invoked from within raise_condition, but we need to prevent recursion befere notifying error to the plugin.

Additionaly, handle_condition must be called once during reporting an error, so the raise_condition is called depending on the result of the handle_condition call.

◆ Protocol_classic

friend class Protocol_classic

friend

◆ push_warning

void push_warning	(	THD *	thd,
		Sql_condition::enum_severity_level	severity,
		uint	code,
		const char *	message_text
	)

friend

Push the warning to error list if there is still room in the list.

Parameters

thd	Thread handle
severity	Severity of warning (note, warning)
code	Error number
message_text	Clear error message

◆ Sql_cmd_common_signal

friend class Sql_cmd_common_signal

friend

◆ Sql_cmd_resignal

friend class Sql_cmd_resignal

friend

◆ Sql_cmd_signal

friend class Sql_cmd_signal

friend

Member Data Documentation

◆ active_vio

Vio* THD::active_vio = {nullptr}

◆ arg_of_last_insert_id_function

bool THD::arg_of_last_insert_id_function

◆ audit_class_mask

Prealloced_array<unsigned long, 11> THD::audit_class_mask

Array of bits indicating which audit classes have already been added to the list of audit plugins which are currently in use.

◆ audit_class_plugins

Plugin_array THD::audit_class_plugins

Array of active audit plugins which have been used by this THD.

This list is later iterated to invoke release_thd() on those plugins.

◆ auto_inc_intervals_forced

Discrete_intervals_list THD::auto_inc_intervals_forced

◆ auto_inc_intervals_in_cur_stmt_for_binlog

Discrete_intervals_list THD::auto_inc_intervals_in_cur_stmt_for_binlog

◆ binlog_accessed_db_names

List<char>* THD::binlog_accessed_db_names

private

◆ binlog_evt_union

struct { ... } THD::binlog_evt_union

◆ binlog_need_explicit_defaults_ts

bool THD::binlog_need_explicit_defaults_ts

The member is served for marking a query that CREATEs or ALTERs a table declared with a TIMESTAMP column as dependent on @session.explicit_defaults_for_timestamp.

Is set to true by parser, unset at the end of the query. Possible marking in checked by binary logger.

◆ binlog_next_event_pos

rpl_event_coordinates THD::binlog_next_event_pos

◆ binlog_row_event_extra_data

uchar* THD::binlog_row_event_extra_data

◆ binlog_table_maps

uint THD::binlog_table_maps

private

◆ binlog_unsafe_warning_flags

uint32 THD::binlog_unsafe_warning_flags

private

Bit field for the state of binlog warnings.

The first Lex::BINLOG_STMT_UNSAFE_COUNT bits list all types of unsafeness that the current statement has.

This must be a member of THD and not of LEX, because warnings are detected and issued in different places (decide_logging_format() and binlog_query(), respectively). Between these calls, the THD->lex object may change; e.g., if a stored routine is invoked. Only THD persists between the calls.

◆ bool_value

bool THD::bool_value

◆ change_list

Item_change_list THD::change_list

◆ charset_is_character_set_filesystem

bool THD::charset_is_character_set_filesystem

◆ charset_is_collation_connection

bool THD::charset_is_collation_connection

◆ charset_is_system_charset

bool THD::charset_is_system_charset

is set if a statement accesses a temporary table created through CREATE TEMPORARY TABLE.

◆ check_for_truncated_fields

enum_check_fields THD::check_for_truncated_fields

◆ cleanup_done

bool THD::cleanup_done

private

◆ col_access

ulong THD::col_access

◆ commit_error

enum THD::Commit_error THD::commit_error

◆ COND_thr_lock

mysql_cond_t THD::COND_thr_lock

Condition variable used for waiting by the THR_LOCK.c subsystem.

◆ convert_buffer

String THD::convert_buffer

◆ current_changed_rows

ulonglong THD::current_changed_rows

Number of rows changed in currently executing statement.

Applicable for UPDATE statements only.

◆ current_cond

std::atomic<mysql_cond_t *> THD::current_cond

Pointer to the condition variable the thread owning this THD is currently waiting for.

If the thread is not waiting, the value is NULL. Set by THD::enter_cond().

If this thread is killed (shutdown or KILL stmt), another thread will broadcast on this condition variable so that the thread can be unstuck.

◆ current_found_rows

ulonglong THD::current_found_rows

Dynamic, collected and set also in subqueries.

Not stable throughout query. previous_found_rows is a snapshot of this take at query end making it stable throughout the next query, see update_previous_found_rows.

◆ current_linfo

LOG_INFO* THD::current_linfo

◆ current_mutex

std::atomic<mysql_mutex_t *> THD::current_mutex

The mutex used with current_cond.

See also: current_cond

◆ current_stmt_binlog_format

enum_binlog_format THD::current_stmt_binlog_format

private

Indicates the format in which the current statement will be logged.

This can only be set from decide_logging_format().

◆ db_charset

const CHARSET_INFO* THD::db_charset

◆ dbug_sentry

uint THD::dbug_sentry

◆ debug_binlog_xid_last

XID THD::debug_binlog_xid_last

◆ DEFAULT_WHERE

const char *const THD::DEFAULT_WHERE = "field list"

static

◆ derived_tables_processing

bool THD::derived_tables_processing

◆ do_union

bool THD::do_union

◆ double_value

double THD::double_value

◆ dup_field

Field* THD::dup_field

◆ duplicate_slave_id

bool THD::duplicate_slave_id

This is only used by master dump threads.

When the master receives a new connection from a slave with a UUID (for slave versions >= 5.6)/server_id(for slave versions < 5.6) that is already connected, it will set this flag true before killing the old slave connection.

◆ durability_property

enum durability_properties THD::durability_property

◆ enable_slow_log

bool THD::enable_slow_log

◆ file_id

uint32 THD::file_id

◆ fill_status_recursion_level

uint THD::fill_status_recursion_level

Used by fill_status() to avoid acquiring LOCK_status mutex twice when this function is called recursively (e.g.

queries that contains SELECT on I_S.GLOBAL_STATUS with subquery on the same I_S table). Incremented each time fill_status() function is entered and decremented each time before it returns from the function.

◆ fill_variables_recursion_level

uint THD::fill_variables_recursion_level

◆ first_query_id

query_id_t THD::first_query_id

◆ first_successful_insert_id_in_cur_stmt

ulonglong THD::first_successful_insert_id_in_cur_stmt

◆ first_successful_insert_id_in_prev_stmt

ulonglong THD::first_successful_insert_id_in_prev_stmt

◆ first_successful_insert_id_in_prev_stmt_for_binlog

ulonglong THD::first_successful_insert_id_in_prev_stmt_for_binlog

◆ global_read_lock

Global_read_lock THD::global_read_lock

◆ got_warning

bool THD::got_warning

◆ ha_data

Prealloced_array<Ha_data, PREALLOC_NUM_HA> THD::ha_data

private

◆ handler_tables_hash

collation_unordered_map<std::string, unique_ptr_my_free<TABLE_LIST> > THD::handler_tables_hash

Initial value:

{&my_charset_latin1,

key_memory_THD_handler_tables_hash}

◆ has_gtid_consistency_violation

bool THD::has_gtid_consistency_violation

◆ in_lock_tables

bool THD::in_lock_tables

◆ in_sub_stmt

uint THD::in_sub_stmt

◆ initial_status_var

struct System_status_var* THD::initial_status_var

◆ insert_lock_default

thr_lock_type THD::insert_lock_default

Type of lock to be used for INSERT statement if lock is not specified explicitly.

Set to TL_WRITE_CONCURRENT_INSERT or TL_WRITE_LOW_PRIORITY depending on whether low_priority_updates option is off or on.

◆ is_a_srv_session_thd

bool THD::is_a_srv_session_thd

private

Variable to mark if the object is part of a Srv_session object, which aggregates THD.

◆ is_commit_in_middle_of_statement

bool THD::is_commit_in_middle_of_statement

◆ is_fatal_error

bool THD::is_fatal_error

Set to true if execution of the current compound statement can not continue.

In particular, disables activation of CONTINUE or EXIT handlers of stored routines. Reset in the end of processing of the current user request, in

See also: mysql_reset_thd_for_next_command().

◆ is_fatal_sub_stmt_error

bool THD::is_fatal_sub_stmt_error

true if we are in a sub-statement and the current error can not be safely recovered until we left the sub-statement mode.

In particular, disables activation of CONTINUE and EXIT handlers inside sub-statements. E.g. if it is a deadlock error and requires a transaction-wide rollback, this flag is raised (traditionally, MySQL first has to close all the reads via

See also: handler::ha_index_or_rnd_end() and only then perform the rollback). Reset to false when we leave the sub-statement mode.

◆ is_killable

bool THD::is_killable

◆ is_operating_gtid_table_implicitly

bool THD::is_operating_gtid_table_implicitly

◆ is_operating_substatement_implicitly

bool THD::is_operating_substatement_implicitly

◆ is_slave_error

bool THD::is_slave_error

True if a slave error.

Causes the slave to stop. Not the same as the statement execution error (is_error()), since a statement may be expected to return an error, e.g. because it returned an error on master, and this is OK on the slave.

◆ kill_immunizer

dd::DD_kill_immunizer* THD::kill_immunizer

When operation on DD tables is in progress then THD is set to kill immune mode.

This member holds DD_kill_immunizer object created to make DD operations immune from the kill operations. Member also indicated whether THD is in kill immune mode or not.

◆ killed

std::atomic<killed_state> THD::killed

◆ lex

LEX* THD::lex

◆ LOCK_current_cond

mysql_mutex_t THD::LOCK_current_cond

Mutex protecting access to current_mutex and current_cond.

◆ lock_info

THR_LOCK_INFO THD::lock_info

◆ LOCK_query_plan

mysql_mutex_t THD::LOCK_query_plan

private

Protects query plan (SELECT/UPDATE/DELETE's) from being freed/changed while another thread explains it.

Following structures are protected by this mutex: THD::Query_plan Modification_plan SELECT_LEX::join JOIN::plan_state Tree of SELECT_LEX_UNIT after THD::Query_plan was set till THD::Query_plan cleanup JOIN_TAB::select->quick Code that changes objects above should take this mutex. Explain code takes this mutex to block changes to named structures to avoid crashes in following functions: explain_single_table_modification explain_query Sql_cmd_explain_other_thread::execute When doing EXPLAIN CONNECTION: all explain code assumes that this mutex is already taken. When doing ordinary EXPLAIN: the mutex does need to be taken (no need to protect reading my own data, moreover EXPLAIN CONNECTION can't run on an ordinary EXPLAIN).

◆ LOCK_thd_data

mysql_mutex_t THD::LOCK_thd_data

Protects THD data accessed from other threads.

The attributes protected are:

thd->is_killable (used by KILL statement and shutdown).
thd->user_vars (user variables, inspected by monitoring) Is locked when THD is deleted.

◆ LOCK_thd_protocol

mysql_mutex_t THD::LOCK_thd_protocol

Protects THD::m_protocol when it gets removed in x plugin.

◆ LOCK_thd_query

mysql_mutex_t THD::LOCK_thd_query

Protects THD::m_query_string.

No other mutexes should be locked while having this mutex locked.

◆ LOCK_thd_sysvar

mysql_mutex_t THD::LOCK_thd_sysvar

Protects THD::variables while being updated.

This should be taken inside of LOCK_thd_data and outside of LOCK_global_system_variables.

◆ locked_tables_list

Locked_tables_list THD::locked_tables_list

◆ long_value

long THD::long_value

◆ m_attachable_trx

Attachable_trx* THD::m_attachable_trx

private

◆ m_binlog_filter_state

binlog_filter_state THD::m_binlog_filter_state

private

Indicate if the current statement should be discarded instead of written to the binlog.

This is used to discard special statements, such as DML or DDL that affects only 'local' (non replicated) tables, such as performance_schema.*

◆ m_binlog_invoker

bool THD::m_binlog_invoker

private

It will be set TURE if CURRENT_USER() is called in account management statements or default definer is set in CREATE/ALTER SP, SF, Event, TRIGGER or VIEW statements.

Current user will be binlogged into Query_log_event if current_user_used is true; It will be stored into m_invoker_host and m_invoker_user by SQL thread.

◆ m_catalog

LEX_CSTRING THD::m_catalog

private

Currently selected catalog.

◆ m_command

enum enum_server_command THD::m_command

private

Type of current query: COM_STMT_PREPARE, COM_QUERY, etc.

Set from first byte of the packet in do_command()

◆ m_cost_model

Cost_model_server THD::m_cost_model

private

Optimizer cost model for server operations.

◆ m_current_query_cost

double THD::m_current_query_cost

Current query cost.

See also: system_status_var::last_query_cost

◆ m_current_query_partial_plans

ulonglong THD::m_current_query_partial_plans

Current query partial plans.

See also: system_status_var::last_query_partial_plans

◆ m_current_stage_key

unsigned int THD::m_current_stage_key

private

◆ m_db

LEX_CSTRING THD::m_db

private

Name of the current (default) database.

If there is the current (default) database, "db" contains its name. If there is no current (default) database, "db" is NULL and "db_length" is 0. In other words, "db", "db_length" must either be NULL, or contain a valid database name.

Note: this attribute is set and alloced by the slave SQL thread (for the THD of that thread); that thread is (and must remain, for now) the only responsible for freeing this member.

◆ m_dd_client

std::unique_ptr<dd::cache::Dictionary_client> THD::m_dd_client

private

◆ m_digest

sql_digest_state* THD::m_digest

Current statement digest.

◆ m_digest_state

sql_digest_state THD::m_digest_state

Top level statement digest.

◆ m_enable_plugins

bool THD::m_enable_plugins

◆ m_examined_row_count

ha_rows THD::m_examined_row_count

private

Number of rows read and/or evaluated for a statement.

Used for slow log reporting.

An examined row is defined as a row that is read and/or evaluated according to a statement condition, including in create_sort_index(). Rows may be counted more than once, e.g., a statement including ORDER BY could possibly evaluate the row in filesort() before reading it for e.g. update.

◆ m_idle_psi

PSI_idle_locker* THD::m_idle_psi

Idle instrumentation.

◆ m_idle_state

PSI_idle_locker_state THD::m_idle_state

Idle instrumentation state.

◆ m_internal_handler

Internal_error_handler* THD::m_internal_handler

private

The current internal error handler for this thread, or NULL.

◆ m_invoker_host

LEX_CSTRING THD::m_invoker_host

private

◆ m_invoker_user

LEX_CSTRING THD::m_invoker_user

private

It points to the invoker in the Query_log_event.

SQL thread use it as the default definer in CREATE/ALTER SP, SF, Event, TRIGGER or VIEW statements or current user in account management statements if it is not NULL.

◆ m_is_plugin_fake_ddl

bool THD::m_is_plugin_fake_ddl

private

Creating or dropping plugin native table through a plugin service.

This variable enables the DDL command execution from dd::create_native_table() to be executed without committing the transaction.

◆ m_main_security_ctx

Security_context THD::m_main_security_ctx

Note: Some members of THD (currently 'Statement::db', 'catalog' and 'query') are set and alloced by the slave SQL thread (for the THD of that thread); that thread is (and must remain, for now) the only responsible for freeing these 3 members. If you add members here, and you add code to set them in replication, don't forget to free_them_and_set_them_to_0 in replication properly. For details see the 'err:' label of the handle_slave_sql() in sql/slave.cc.

See also: handle_slave_sql

◆ m_net_server_extension

NET_SERVER THD::m_net_server_extension

Aditional network instrumentation for the server only.

◆ m_normalized_query

String THD::m_normalized_query

private

◆ m_parser_da

Diagnostics_area THD::m_parser_da

private

cf.

get_parser_da()

◆ m_parser_state

Parser_state* THD::m_parser_state

Internal parser state.

Note that since the parser is not re-entrant, we keep only one parser state here. This member is valid only when executing code during parsing.

◆ m_protocol

Protocol* THD::m_protocol

private

◆ m_psi

std::atomic<PSI_thread *> THD::m_psi

private

Performance schema thread instrumentation for this session.

This member is maintained using atomic operations, do not access it directly.

See also: set_psi; get_psi

◆ m_query_rewrite_plugin_da

Diagnostics_area THD::m_query_rewrite_plugin_da

private

◆ m_query_rewrite_plugin_da_ptr

Diagnostics_area* THD::m_query_rewrite_plugin_da_ptr

private

◆ m_query_string

LEX_CSTRING THD::m_query_string

private

The query associated with this statement.

◆ m_release_resources_done

bool THD::m_release_resources_done

private

◆ m_resource_group_ctx

resourcegroups::Resource_group_ctx THD::m_resource_group_ctx

private

Resource group context indicating the current resource group and the name of the resource group to switch to during execution of a query.

◆ m_row_count_func

longlong THD::m_row_count_func

private

Stores the result of ROW_COUNT() function.

ROW_COUNT() function is a MySQL extention, but we try to keep it similar to ROW_COUNT member of the GET DIAGNOSTICS stack of the SQL standard (see SQL99, part 2, search for ROW_COUNT). It's value is implementation defined for anything except INSERT, DELETE, UPDATE.

ROW_COUNT is assigned according to the following rules:

In my_ok():
- for DML statements: to the number of affected rows;
- for DDL statements: to 0.
In my_eof(): to -1 to indicate that there was a result set.

We derive this semantics from the JDBC specification, where int java.sql.Statement.getUpdateCount() is defined to (sic) "return the current result as an update count; if the result is a ResultSet object or there are no more results, -1 is returned".
In my_error(): to -1 to be compatible with the MySQL C API and MySQL ODBC driver.
For SIGNAL statements: to 0 per WL#2110 specification (see also sql_signal.cc comment). Zero is used since that's the "default" value of ROW_COUNT in the Diagnostics Area.

◆ m_security_ctx

Security_context* THD::m_security_ctx

◆ m_sent_row_count

ha_rows THD::m_sent_row_count

private

Number of rows we actually sent to the client, including "synthetic" rows in ROLLUP etc.

◆ m_server_idle

bool THD::m_server_idle

True if the server code is IDLE for this connection.

◆ m_SSL

SSL_handle THD::m_SSL = {nullptr}

private

SSL data attached to this connection.

This is an opaque pointer, When building with SSL, this pointer is non NULL only if the connection is using SSL. When building without SSL, this pointer is always NULL. The SSL data can be inspected to read per thread status variables, and this can be inspected while the thread is running.

◆ m_stage_progress_psi

PSI_stage_progress* THD::m_stage_progress_psi

Current stage progress instrumentation.

◆ m_statement_psi

PSI_statement_locker* THD::m_statement_psi

Current statement instrumentation.

◆ m_statement_state

PSI_statement_locker_state THD::m_statement_state

Current statement instrumentation state.

◆ m_stmt_da

Diagnostics_area* THD::m_stmt_da

private

◆ m_thread_id

my_thread_id THD::m_thread_id

private

This counter is 32 bit because of the client protocol.

Note: It is not meant to be used for my_thread_self(), see real_id for this.; Set to reserved_thread_id on initialization. This is a magic value that is only to be used for temporary THDs not present in the global THD list.

◆ m_token_array

unsigned char* THD::m_token_array

Current statement digest token array.

◆ m_trans_end_pos

my_off_t THD::m_trans_end_pos

private

◆ m_trans_fixed_log_file

char* THD::m_trans_fixed_log_file

private

◆ m_trans_log_file

const char* THD::m_trans_log_file

private

The binary log position of the transaction.

The file and position are zero if the current transaction has not been written to the binary log.

See also: set_trans_pos; get_trans_pos

◆ m_transaction

std::unique_ptr<Transaction_ctx> THD::m_transaction

private

◆ m_transaction_psi

PSI_transaction_locker* THD::m_transaction_psi

Current transaction instrumentation.

◆ m_transaction_state

PSI_transaction_locker_state THD::m_transaction_state

Current transaction instrumentation state.

◆ m_user_connect

USER_CONN* THD::m_user_connect

private

◆ m_view_ctx_list

List<Security_context> THD::m_view_ctx_list

◆ main_da

Diagnostics_area THD::main_da

private

◆ main_lex

std::unique_ptr<LEX> THD::main_lex

private

The lex to hold the parsed tree of conventional (non-prepared) queries.

Whereas for prepared and stored procedure statements we use an own lex instance for each new query, for conventional statements we reuse the same lex. (

See also: mysql_parse for details).

◆ main_mem_root

MEM_ROOT THD::main_mem_root

private

This memory root is used for two purposes:

for conventional queries, to allocate structures stored in main_lex during parsing, and allocate runtime data (execution plan, etc.) during execution.
for prepared queries, only to allocate runtime data. The parsed tree itself is reused between executions and thus is stored elsewhere.

◆ mark_used_columns

enum enum_mark_columns THD::mark_used_columns

◆ max_client_packet_length

ulong THD::max_client_packet_length

◆ mdl_context

MDL_context THD::mdl_context

◆ net

NET THD::net

private

◆ next_to_commit

THD* THD::next_to_commit

Used by MYSQL_BIN_LOG to maintain the commit queue for binary log group commit.

◆ num_truncated_fields

ha_rows THD::num_truncated_fields

◆ open_options

uint THD::open_options

◆ opt_trace

Opt_trace_context THD::opt_trace

optimizer trace of current statement

◆ owned_gtid

Gtid THD::owned_gtid

The GTID of the currently owned transaction.

==== Modes of ownership ====

The following modes of ownership are possible:

owned_gtid.sidno==0: the thread does not own any transaction.
owned_gtid.sidno==THD::OWNED_SIDNO_ANONYMOUS(==-2): the thread owns an anonymous transaction
owned_gtid.sidno>0 and owned_gtid.gno>0: the thread owns a GTID transaction.
(owned_gtid.sidno==THD::OWNED_SIDNO_GTID_SET(==-1): this is currently not used. It was reserved for the case where multiple GTIDs are owned (using gtid_next_list). This was one idea to make GTIDs work with NDB: due to the epoch concept, multiple transactions can be combined into one in NDB, and therefore a single transaction on a slave can have multiple GTIDs.)

==== Life cycle of ownership ====

Generally, transaction ownership starts when the transaction is assigned its GTID and ends when the transaction commits or rolls back. On a master (GTID_NEXT=AUTOMATIC), the GTID is assigned just before binlog flush; on a slave (GTID_NEXT=UUID:NUMBER or GTID_NEXT=ANONYMOUS) it is assigned before starting the transaction.

A new client always starts with owned_gtid.sidno=0.

Ownership can be acquired in the following ways:

A1. If GTID_NEXT = 'AUTOMATIC' and GTID_MODE = OFF/OFF_PERMISSIVE: The thread acquires anonymous ownership in gtid_state->generate_automatic_gtid called from MYSQL_BIN_LOG::write_gtid.

A2. If GTID_NEXT = 'AUTOMATIC' and GTID_MODE = ON/ON_PERMISSIVE: The thread generates the GTID and acquires ownership in gtid_state->generate_automatic_gtid called from MYSQL_BIN_LOG::write_gtid.

A3. If GTID_NEXT = 'UUID:NUMBER': The thread acquires ownership in the following ways:

In a client, the SET GTID_NEXT statement acquires ownership.
The slave's analogy to a clients SET GTID_NEXT statement is Gtid_log_event::do_apply_event. So the slave acquires ownership in this function.

Note: if the GTID UUID:NUMBER is already included in GTID_EXECUTED, then the transaction must be skipped (the GTID auto-skip feature). Thus, ownership is not acquired in this case and owned_gtid.sidno==0.

A4. If GTID_NEXT = 'ANONYMOUS':

- In a client, the SET GTID_NEXT statement acquires ownership.

- In a slave thread, Gtid_log_event::do_apply_event acquires
  ownership.

- Contrary to the case of GTID_NEXT='UUID:NUMBER', it is
  allowed to execute two transactions in sequence without
  changing GTID_NEXT (cf. R1 and R2 below).  Both transactions
  should be executed as anonymous transactions.  But ownership
  is released when the first transaction commits.  Therefore,
  when GTID_NEXT='ANONYMOUS', we also acquire anonymous
  ownership when starting to execute a statement, in
  gtid_reacquire_ownership_if_anonymous called from
  gtid_pre_statement_checks (usually called from
  mysql_execute_command).

A5. Slave applier threads start in a special mode, having GTID_NEXT='NOT_YET_DETERMINED'. This mode cannot be set in a regular client. When GTID_NEXT=NOT_YET_DETERMINED, the slave thread is postponing the decision of the value of GTID_NEXT until it has more information. There are three cases:

If the first transaction of the relay log has a Gtid_log_event, then it will set GTID_NEXT=GTID:NUMBER and acquire GTID ownership in Gtid_log_event::do_apply_event.
If the first transaction of the relay log has a Anonymous_gtid_log_event, then it will set GTID_NEXT=ANONYMOUS and acquire anonymous ownership in Gtid_log_event::do_apply_event.
If the relay log was received from a pre-5.7.6 master with GTID_MODE=OFF (or a pre-5.6 master), then there are neither Gtid_log_events nor Anonymous_log_events in the relay log. In this case, the slave sets GTID_NEXT=ANONYMOUS and acquires anonymous ownership when executing a Query_log_event (Query_log_event::do_apply_event calls mysql_parse which calls gtid_pre_statement_checks which calls gtid_reacquire_ownership_if_anonymous).

Ownership is released in the following ways:

R1. A thread that holds GTID ownership releases ownership at transaction commit or rollback. If GTID_NEXT=AUTOMATIC, all is fine. If GTID_NEXT=UUID:NUMBER, the UUID:NUMBER cannot be used for another transaction, since only one transaction can have any given GTID. To avoid the user mistake of forgetting to set back GTID_NEXT, on commit we set thd->variables.gtid_next.type=UNDEFINED_GTID. Then, any statement that user tries to execute other than SET GTID_NEXT will generate an error.

R2. A thread that holds anonymous ownership releases ownership at transaction commit or rollback. In this case there is no harm in leaving GTID_NEXT='ANONYMOUS', so thd->variables.gtid_next.type will remain ANONYMOUS_GTID and not UNDEFINED_GTID.

There are statements that generate multiple transactions in the binary log. This includes the following:

M1. DROP TABLE that is used with multiple tables, and the tables belong to more than one of the following groups: non-temporary table, temporary transactional table, temporary non-transactional table. DROP TABLE is split into one transaction for each of these groups of tables.

M2. DROP DATABASE that fails e.g. because rmdir fails. Then a single DROP TABLE is generated, which lists all tables that were dropped before the failure happened. But if the list of tables is big, and grows over a limit, the statement will be split into multiple statements.

M3. CREATE TABLE ... SELECT that is logged in row format. Then the server generates a single CREATE statement, followed by a BEGIN ... row events ... COMMIT transaction.

M4. A statement that updates both transactional and non-transactional tables in the same statement, and is logged in row format. Then it generates one transaction for the non-transactional row updates, followed by one transaction for the transactional row updates.

M5. CALL is executed as multiple transactions and logged as multiple transactions.

The general rules for multi-transaction statements are:

If GTID_NEXT=AUTOMATIC and GTID_MODE=ON or ON_PERMISSIVE, one GTID should be generated for each transaction within the statement. Therefore, ownership must be released after each commit so that a new GTID can be generated by the next transaction. Typically mysql_bin_log.commit() is called to achieve this. (Note that some of these statements are currently disallowed when GTID_MODE=ON.)
If GTID_NEXT=AUTOMATIC and GTID_MODE=OFF or OFF_PERMISSIVE, one Anonymous_gtid_log_event should be generated for each transaction within the statement. Similar to the case above, we call mysql_bin_log.commit() and release ownership between transactions within the statement.

This works for all the special cases M1-M5 except M4. When a statement writes both non-transactional and transactional updates to the binary log, both the transaction cache and the statement cache are flushed within the same call to flush_thread_caches(THD) from within the binary log group commit code. At that point we cannot use mysql_bin_log.commit(). Instead we release ownership using direct calls to gtid_state->release_anonymous_ownership() and thd->clear_owned_gtids() from binlog_cache_mngr::flush.
If GTID_NEXT=ANONYMOUS, anonymous ownership must be preserved between transactions within the statement, to prevent that a concurrent SET GTID_MODE=ON makes it impossible to log the statement. To avoid that ownership is released if mysql_bin_log.commit() is called, we set thd->is_commit_in_middle_of_statement before calling mysql_bin_log.commit. Note that we must set this flag only if GTID_NEXT=ANONYMOUS, not if the transaction is anonymous when GTID_NEXT=AUTOMATIC and GTID_MODE=OFF.

This works for all the special cases M1-M5 except M4. When a statement writes non-transactional updates in the middle of a transaction, but keeps some transactional updates in the transaction cache, then it is not easy to know at the time of calling mysql_bin_log.commit() whether anonymous ownership needs to be preserved or not. Instead, we directly check if the transaction cache is nonempty before releasing anonymous ownership inside Gtid_state::update_gtids_impl.
If GTID_NEXT='UUID:NUMBER', it is impossible to log a multi-transaction statement, since each GTID can only be used by one transaction. Therefore, an error must be generated in this case. Errors are generated in different ways for the different statement types:
- DROP TABLE: we can detect the situation before it happens, since the table type is known once the tables are opened. So we generate an error before even executing the statement.
- DROP DATABASE: we can't detect the situation until it is too late; the tables have already been dropped and we cannot log anything meaningful. So we don't log at all.
- CREATE TABLE ... SELECT: this is not allowed when enforce_gtid_consistency is ON; the statement will be forbidden in is_ddl_gtid_compatible.
- Statements that update both transactional and non-transactional tables are disallowed when GTID_MODE=ON, so this normally does not happen. However, it can happen if the slave uses a different engine type than the master, so that a statement that updates InnoDB+InnoDB on master updates InnoDB+MyISAM on slave. In this case the statement will be forbidden in is_dml_gtid_compatible and will not be allowed to execute.
- CALL: the second statement will generate an error because GTID_NEXT is 'undefined'. Note that this situation can only happen if user does it on purpose: A CALL on master is logged as multiple statements, so a slave never executes CALL with GTID_NEXT='UUID:NUMBER'.

Finally, ownership release is suppressed in one more corner case:

C1. Administration statements including OPTIMIZE TABLE, REPAIR TABLE, or ANALYZE TABLE are written to the binary log even if they fail. This means that the thread first calls trans_rollack, and then writes the statement to the binlog. Rollback normally releases ownership. But ownership must be kept until writing the binlog. The solution is that these statements set thd->skip_gtid_rollback=true before calling trans_rollback, and Gtid_state::update_on_rollback does not release ownership if the flag is set.

◆ owned_sid

rpl_sid THD::owned_sid

For convenience, this contains the SID component of the GTID stored in owned_gtid.

◆ OWNED_SIDNO_ANONYMOUS

const int THD::OWNED_SIDNO_ANONYMOUS = -2

static

◆ OWNED_SIDNO_GTID_SET

const int THD::OWNED_SIDNO_GTID_SET = -1

static

◆ packet

String THD::packet

private

◆ parsing_system_view

bool THD::parsing_system_view

◆ password

uchar THD::password

◆ peer_port

uint16 THD::peer_port

◆ previous_found_rows

ulonglong THD::previous_found_rows

Stores the result of the FOUND_ROWS() function.

Set at query end, stable throughout the query.

◆ proc_info

const char* THD::proc_info

◆ profiling

std::unique_ptr<PROFILING> THD::profiling

◆ protocol_binary

Protocol_binary THD::protocol_binary

◆ protocol_text

Protocol_text THD::protocol_text

◆ query_id

query_id_t THD::query_id

◆ query_name_consts

uint THD::query_name_consts

number of name_const() substitutions, see sp_head.cc:subst_spvars()

◆ query_plan

class THD::Query_plan THD::query_plan

◆ query_start_usec_used

bool THD::query_start_usec_used

◆ rand

struct rand_struct THD::rand

◆ rand_saved_seed1

ulong THD::rand_saved_seed1

◆ rand_saved_seed2

ulong THD::rand_saved_seed2

◆ rand_used

bool THD::rand_used

◆ real_id

my_thread_t THD::real_id

◆ rewritten_query

String THD::rewritten_query

In some cases, we may want to modify the query (i.e.

replace passwords with their hashes before logging the statement etc.).

In case the query was rewritten, the original query will live in m_query_string, while the rewritten query lives in rewritten_query. If rewritten_query is empty, m_query_string should be logged. If rewritten_query is non-empty, the rewritten query it contains should be used in logs (general log, slow query log, binary log).

Currently, password obfuscation is the only rewriting we do; more may follow at a later date, both pre- and post parsing of the query. Rewriting of binloggable statements must preserve all pertinent information.

◆ rli_fake

Relay_log_info* THD::rli_fake

◆ rli_slave

Relay_log_info* THD::rli_slave

◆ rpl_thd_ctx

Rpl_thd_context THD::rpl_thd_ctx

◆ scheduler

thd_scheduler THD::scheduler

◆ scramble

char THD::scramble[SCRAMBLE_LENGTH+1]

◆ server_id

uint32 THD::server_id

◆ server_status

uint THD::server_status

◆ session_sysvar_res_mgr

Session_sysvar_resource_manager THD::session_sysvar_res_mgr

◆ session_tracker

Session_tracker THD::session_tracker

◆ skip_gtid_rollback

bool THD::skip_gtid_rollback

◆ skip_readonly_check

bool THD::skip_readonly_check

private

◆ slave_thread

bool THD::slave_thread

◆ sp_func_cache

sp_cache* THD::sp_func_cache

◆ sp_proc_cache

sp_cache* THD::sp_proc_cache

◆ sp_runtime_ctx

sp_rcontext* THD::sp_runtime_ctx

Current SP-runtime context.

◆ start_time

struct timeval THD::start_time

◆ start_utime

ulonglong THD::start_utime

◆ statement_id_counter

ulong THD::statement_id_counter

◆ status_var

struct System_status_var THD::status_var

◆ status_var_aggregated

bool THD::status_var_aggregated

◆ stmt_arena

Query_arena* THD::stmt_arena

◆ stmt_depends_on_first_successful_insert_id_in_prev_stmt

bool THD::stmt_depends_on_first_successful_insert_id_in_prev_stmt

◆ stmt_map

Prepared_statement_map THD::stmt_map

All prepared statements of this connection.

◆ substitute_null_with_insert_id

bool THD::substitute_null_with_insert_id

◆ sys_var_tmp

union { ... } THD::sys_var_tmp

◆ system_thread

enum enum_thread_type THD::system_thread

◆ table_map_for_update

table_map THD::table_map_for_update

◆ thd_tx_priority

int THD::thd_tx_priority

◆ thread_specific_used

bool THD::thread_specific_used

is set if some thread specific value(s) used in a statement.

◆ thread_stack

const char* THD::thread_stack

◆ time_zone_used

bool THD::time_zone_used

◆ timer

struct THD_timer_info* THD::timer

Holds active timer object.

◆ timer_cache

struct THD_timer_info* THD::timer_cache

After resetting(cancelling) timer, current timer object is cached with timer_cache timer to reuse.

◆ tmp_table

uint THD::tmp_table

◆ tmp_table_seq_id

uint THD::tmp_table_seq_id

private

Sequential number of internal tmp table created in the statement.

Useful for tracking tmp tables when number of them is involved in a query.

◆ transaction_rollback_request

bool THD::transaction_rollback_request

Set by a storage engine to request the entire transaction (that possibly spans multiple engines) to rollback.

Reset in ha_rollback.

◆ tx_isolation

enum_tx_isolation THD::tx_isolation

◆ tx_priority

int THD::tx_priority

◆ tx_read_only

bool THD::tx_read_only

◆ ull_hash

malloc_unordered_map<std::string, User_level_lock *> THD::ull_hash

Initial value:

{

key_memory_User_level_lock}

◆ ulong_value

ulong THD::ulong_value

◆ ulonglong_value

ulonglong THD::ulonglong_value

◆ unioned_events

bool THD::unioned_events

◆ unioned_events_trans

bool THD::unioned_events_trans

◆ unmasked_server_id

uint32 THD::unmasked_server_id

◆ update_lock_default

thr_lock_type THD::update_lock_default

Type of lock to be used for all DML statements, except INSERT, in cases when lock is not specified explicitly.

Set to TL_WRITE or TL_WRITE_LOW_PRIORITY depending on whether low_priority_updates option is off or on.

◆ user_time

struct timeval THD::user_time

◆ user_var_events

Prealloced_array<Binlog_user_var_event *, 2> THD::user_var_events

◆ user_var_events_alloc

MEM_ROOT* THD::user_var_events_alloc

◆ user_vars

collation_unordered_map<std::string, unique_ptr_with_deleter<user_var_entry> > THD::user_vars {system_charset_info, key_memory_user_var_entry}

Hash for user variables.

User variables are per session, but can also be monitored outside of the session, so a lock is needed to prevent race conditions. Protected by LOCK_thd_data.

◆ utime_after_lock

ulonglong THD::utime_after_lock

◆ variables

struct System_variables THD::variables

◆ waiting_for_disk_space

bool THD::waiting_for_disk_space = false

private

◆ want_privilege

ulong THD::want_privilege

Used by Item::check_column_privileges() to tell which privileges to check for.

Set to ~0ULL before starting to resolve a statement. Set to desired privilege mask before calling a resolver function that will call Item::check_column_privileges(). After use, restore previous value as current value.

◆ where

const char* THD::where

◆ work_part_info

partition_info* THD::work_part_info

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

Classes

Public Types

Public Member Functions

Static Public Member Functions

Public Attributes

Static Public Attributes

Private Member Functions

Private Attributes

Friends

Detailed Description

Member Enumeration Documentation

◆ binlog_filter_state

◆ Commit_error

◆ enum_binlog_query_type

◆ enum_reset_lex

◆ killed_state

Constructor & Destructor Documentation

◆ THD()

◆ ~THD()

Member Function Documentation

◆ awake()

◆ backup_ha_data()

◆ begin_attachable_ro_transaction()

◆ begin_attachable_rw_i_s_transaction()

◆ begin_attachable_rw_transaction()

◆ begin_attachable_transaction()

◆ binlog_flush_pending_rows_event()

◆ binlog_invoker()

◆ catalog()

◆ change_item_tree()

◆ charset()

◆ claim_memory_ownership()

◆ cleanup()

◆ cleanup_after_query()

◆ cleanup_connection()

◆ clear_active_vio()

◆ clear_binlog_local_stmt_filter()

◆ clear_binlog_table_maps()

◆ clear_current_query_costs()

◆ clear_current_stmt_binlog_format_row()

◆ clear_error()

◆ clear_next_event_pos()

◆ clear_owned_gtids()

◆ collation()

◆ convert_string() [1/2]

◆ convert_string() [2/2]

◆ copy_db_to() [1/2]

◆ copy_db_to() [2/2]

◆ cost_model()

◆ db()

◆ dd_client()

◆ debug_assert_query_locked()

◆ decrement_user_connections_counter()

◆ disconnect()

◆ end_attachable_transaction()

◆ end_statement()

◆ enter_cond()

◆ enter_locked_tables_mode()

◆ enter_stage()

◆ exit_cond()

◆ fatal_error()

◆ fill_information_schema_tables()

◆ force_one_auto_inc_interval()

◆ found_rows()

◆ get_binlog_accessed_db_names()

◆ get_binlog_local_stmt_filter()

◆ get_binlog_table_maps()

◆ get_command()

◆ get_definer()

◆ get_examined_row_count()

◆ get_gtid_next_list()

◆ get_gtid_next_list_const()

◆ get_ha_data()

◆ get_internal_handler()

◆ get_invoker_host()

◆ get_invoker_user()

◆ get_parser_da()

◆ get_proc_info()

◆ get_protocol()

◆ get_protocol_classic()