MySQL  8.0.19
Source Code Documentation
Sys_var_session_special Class Reference

The class for variables that have a special meaning for a session, such as @timestamp or @rnd_seed1, their values typically cannot be read from SV structure, and a special "read" callback is provided. More...

#include <sys_vars.h>

Inheritance diagram for Sys_var_session_special:
Sys_var_integer< T, ARGT, SHOWT, SIGNED >

Public Member Functions

 Sys_var_session_special (const char *name_arg, const char *comment, int flag_args, CMD_LINE getopt, ulonglong min_val, ulonglong max_val, uint block_size, PolyLock *lock, enum binlog_status_enum binlog_status_arg, on_check_function on_check_func, session_special_update_function update_func_arg, session_special_read_function read_func_arg, const char *substitute=0)
 
bool session_update (THD *thd, set_var *var)
 
bool global_update (THD *, set_var *)
 
void session_save_default (THD *, set_var *var)
 
void global_save_default (THD *, set_var *)
 
void saved_value_to_string (THD *, set_var *, char *)
 
const ucharsession_value_ptr (THD *running_thd, THD *target_thd, LEX_STRING *)
 
const ucharglobal_value_ptr (THD *, LEX_STRING *)
 
- Public Member Functions inherited from Sys_var_integer< T, ARGT, SHOWT, SIGNED >
 Sys_var_integer (const char *name_arg, const char *comment, int flag_args, ptrdiff_t off, size_t size, CMD_LINE getopt, T min_val, T max_val, T def_val, uint block_size, PolyLock *lock=0, enum binlog_status_enum binlog_status_arg=VARIABLE_NOT_IN_BINLOG, on_check_function on_check_func=0, on_update_function on_update_func=0, const char *substitute=0, int parse_flag=PARSE_NORMAL)
 
bool do_check (THD *thd, set_var *var)
 
bool session_update (THD *thd, set_var *var)
 
bool global_update (THD *, set_var *var)
 
bool check_update_type (Item_result type)
 
void session_save_default (THD *thd, set_var *var)
 
void global_save_default (THD *, set_var *var)
 
void saved_value_to_string (THD *, set_var *var, char *def_val)
 

Private Types

typedef bool(* session_special_update_function) (THD *thd, set_var *var)
 
typedef ulonglong(* session_special_read_function) (THD *thd)
 

Private Attributes

session_special_read_function read_func
 
session_special_update_function update_func
 

Detailed Description

The class for variables that have a special meaning for a session, such as @timestamp or @rnd_seed1, their values typically cannot be read from SV structure, and a special "read" callback is provided.

Class specific constructor arguments: everything derived from Sys_var_ulonglong session_special_read_function read_func_arg

Backing store: ulonglong

Note
These variables are session-only, global or command-line equivalents are not supported as they're generally meaningless.

Member Typedef Documentation

◆ session_special_read_function

typedef ulonglong(* Sys_var_session_special::session_special_read_function) (THD *thd)
private

◆ session_special_update_function

typedef bool(* Sys_var_session_special::session_special_update_function) (THD *thd, set_var *var)
private

Constructor & Destructor Documentation

◆ Sys_var_session_special()

Sys_var_session_special::Sys_var_session_special ( const char *  name_arg,
const char *  comment,
int  flag_args,
CMD_LINE  getopt,
ulonglong  min_val,
ulonglong  max_val,
uint  block_size,
PolyLock lock,
enum binlog_status_enum  binlog_status_arg,
on_check_function  on_check_func,
session_special_update_function  update_func_arg,
session_special_read_function  read_func_arg,
const char *  substitute = 0 
)
inline

Member Function Documentation

◆ global_save_default()

void Sys_var_session_special::global_save_default ( THD ,
set_var  
)
inline

◆ global_update()

bool Sys_var_session_special::global_update ( THD ,
set_var  
)
inline

◆ global_value_ptr()

const uchar* Sys_var_session_special::global_value_ptr ( THD ,
LEX_STRING  
)
inline

◆ saved_value_to_string()

void Sys_var_session_special::saved_value_to_string ( THD ,
set_var ,
char *   
)
inline

◆ session_save_default()

void Sys_var_session_special::session_save_default ( THD ,
set_var var 
)
inline

◆ session_update()

bool Sys_var_session_special::session_update ( THD thd,
set_var var 
)
inline

◆ session_value_ptr()

const uchar* Sys_var_session_special::session_value_ptr ( THD running_thd,
THD target_thd,
LEX_STRING  
)
inline

Member Data Documentation

◆ read_func

session_special_read_function Sys_var_session_special::read_func
private

◆ update_func

session_special_update_function Sys_var_session_special::update_func
private

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