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cleanup: string sys_var types

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Merge sys_var_charptr with sys_var_charptr_base, as well as merge
Sys_var_session_lexstring into Sys_var_lexstring. Also refactored
update methods of sys_var_charptr accordingly.

Because the class is more generic, session_update() calls
sys_var_charptr::session_update() which does not assume a buffer field
associated with THD, but instead call strdup/free, we get rid of
THD::default_master_connection_buff accordingly. This also makes THD
smaller by ~192 bytes, and there can be many thousands of concurrent
THDs.
This commit is contained in:
Yuchen Pei 2023-09-14 10:32:42 +10:00
parent d16817c477
commit 6151bde48c
No known key found for this signature in database
GPG Key ID: 3DD1B35105743563
7 changed files with 102 additions and 138 deletions
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10
mysql-test/suite/sys_vars/r/mdev_15935.result Normal file
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@ -0,0 +1,10 @@
#
# test cleanup of sys_var classes
#
set global init_connect=".................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................";
ERROR HY000: String '......................................................................' is too long for init_connect (should be no longer than 2000)
set global ft_boolean_syntax=".................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................";
ERROR HY000: String '......................................................................' is too long for ft_boolean_syntax (should be no longer than 2000)
#
# end of test mdev_15935
#

13
mysql-test/suite/sys_vars/t/mdev_15935.test Normal file
View File

@ -0,0 +1,13 @@
--echo #
--echo # test cleanup of sys_var classes
--echo #
--let $long_string=`select repeat('.', 2001)`
--error ER_WRONG_STRING_LENGTH
eval set global init_connect="$long_string";
--error ER_WRONG_STRING_LENGTH
eval set global ft_boolean_syntax="$long_string";
--echo #
--echo # end of test mdev_15935
--echo #

5
sql/sql_class.cc
View File

@ -1235,10 +1235,7 @@ void THD::init()
avoid temporary tables replication failure.
*/
variables.pseudo_thread_id= thread_id;
variables.default_master_connection.str= default_master_connection_buff;
::strmake(default_master_connection_buff,
global_system_variables.default_master_connection.str,
variables.default_master_connection.length);
mysql_mutex_unlock(&LOCK_global_system_variables);
user_time.val= start_time= start_time_sec_part= 0;

1
sql/sql_class.h
View File

@ -3750,7 +3750,6 @@ public:
This is used for taging error messages in the log files.
*/
LEX_CSTRING connection_name;
char default_master_connection_buff[MAX_CONNECTION_NAME+1];
uint8 password; /* 0, 1 or 2 */
uint8 failed_com_change_user;
bool slave_thread;

11
sql/sql_plugin.cc
View File

@ -3279,6 +3279,9 @@ void plugin_thdvar_init(THD *thd)
#ifndef EMBEDDED_LIBRARY
thd->session_tracker.sysvars.deinit(thd);
#endif
my_free((char*) thd->variables.default_master_connection.str);
thd->variables.default_master_connection.str= 0;
thd->variables.default_master_connection.length= 0;
thd->variables= global_system_variables;
@ -3301,6 +3304,11 @@ void plugin_thdvar_init(THD *thd)
intern_plugin_unlock(NULL, old_enforced_table_plugin);
mysql_mutex_unlock(&LOCK_plugin);
thd->variables.default_master_connection.str=
my_strndup(key_memory_Sys_var_charptr_value,
global_system_variables.default_master_connection.str,
global_system_variables.default_master_connection.length,
MYF(MY_WME | MY_THREAD_SPECIFIC));
#ifndef EMBEDDED_LIBRARY
thd->session_tracker.sysvars.init(thd);
#endif
@ -3372,6 +3380,9 @@ void plugin_thdvar_cleanup(THD *thd)
#ifndef EMBEDDED_LIBRARY
thd->session_tracker.sysvars.deinit(thd);
#endif
my_free((char*) thd->variables.default_master_connection.str);
thd->variables.default_master_connection.str= 0;
thd->variables.default_master_connection.length= 0;
mysql_mutex_lock(&LOCK_plugin);

7
sql/sys_vars.cc
View File

@ -1346,12 +1346,11 @@ static bool check_master_connection(sys_var *self, THD *thd, set_var *var)
return false;
}
static Sys_var_session_lexstring Sys_default_master_connection(
static Sys_var_lexstring Sys_default_master_connection(
"default_master_connection",
"Master connection to use for all slave variables and slave commands",
SESSION_ONLY(default_master_connection),
NO_CMD_LINE,
DEFAULT(""), MAX_CONNECTION_NAME, ON_CHECK(check_master_connection));
SESSION_ONLY(default_master_connection), NO_CMD_LINE, DEFAULT(""),
NO_MUTEX_GUARD, NOT_IN_BINLOG, ON_CHECK(check_master_connection));
#endif
static Sys_var_charptr_fscs Sys_init_file(

193
sql/sys_vars.inl
View File

@ -492,14 +492,18 @@ public:
Backing store: char*
@note
This class supports only GLOBAL variables, because THD on destruction
does not destroy individual members of SV, there's no way to free
allocated string variables for every thread.
Note that the memory management for SESSION_VAR's is manual, the
value must be strdup'ed in THD::init() and freed in
plugin_thdvar_cleanup(). TODO: it should be done automatically when
we'll have more session string variables to justify it. Maybe some
kind of a loop over all variables, like sys_var_end() in set_var.cc?
*/
class Sys_var_charptr_base: public sys_var
class Sys_var_charptr: public sys_var
{
const size_t max_length= 2000;
public:
Sys_var_charptr_base(const char *name_arg,
Sys_var_charptr(const char *name_arg,
const char *comment, int flag_args, ptrdiff_t off, size_t size,
CMD_LINE getopt,
const char *def_val, PolyLock *lock=0,
@ -519,8 +523,9 @@ public:
*/
option.var_type|= (flags & ALLOCATED) ? GET_STR_ALLOC : GET_STR;
global_var(const char*)= def_val;
SYSVAR_ASSERT(size == sizeof(char *));
}
void cleanup()
void cleanup() override
{
if (flags & ALLOCATED)
{
@ -558,17 +563,26 @@ public:
return false;
}
bool do_check(THD *thd, set_var *var)
{ return do_string_check(thd, var, charset(thd)); }
bool session_update(THD *thd, set_var *var)= 0;
char *global_update_prepare(THD *thd, set_var *var)
bool do_check(THD *thd, set_var *var) override
{
if (do_string_check(thd, var, charset(thd)))
return true;
if (var->save_result.string_value.length > max_length)
{
my_error(ER_WRONG_STRING_LENGTH, MYF(0), var->save_result.string_value.str,
name.str, (int) max_length);
return true;
}
return false;
}
char *update_prepare(set_var *var, myf my_flags)
{
char *new_val, *ptr= var->save_result.string_value.str;
size_t len=var->save_result.string_value.length;
if (ptr)
{
new_val= (char*)my_memdup(key_memory_Sys_var_charptr_value,
ptr, len+1, MYF(MY_WME));
ptr, len+1, my_flags);
if (!new_val) return 0;
new_val[len]=0;
}
@ -576,6 +590,13 @@ public:
new_val= 0;
return new_val;
}
bool session_update(THD *thd, set_var *var) override
{
char *new_val= update_prepare(var, MYF(MY_WME | MY_THREAD_SPECIFIC));
my_free(session_var(thd, char*));
session_var(thd, char*)= new_val;
return (new_val == 0 && var->save_result.string_value.str != 0);
}
void global_update_finish(char *new_val)
{
if (flags & ALLOCATED)
@ -583,14 +604,19 @@ public:
flags|= ALLOCATED;
global_var(char*)= new_val;
}
bool global_update(THD *thd, set_var *var)
bool global_update(THD *thd, set_var *var) override
{
char *new_val= global_update_prepare(thd, var);
char *new_val= update_prepare(var, MYF(MY_WME));
global_update_finish(new_val);
return (new_val == 0 && var->save_result.string_value.str != 0);
}
void session_save_default(THD *thd, set_var *var)= 0;
void global_save_default(THD *thd, set_var *var)
void session_save_default(THD *, set_var *var) override
{
var->save_result.string_value.str= global_var(char*);
var->save_result.string_value.length=
strlen(var->save_result.string_value.str);
}
void global_save_default(THD *, set_var *var) override
{
char *ptr= (char*)(intptr)option.def_value;
var->save_result.string_value.str= ptr;
@ -598,35 +624,6 @@ public:
}
};
class Sys_var_charptr: public Sys_var_charptr_base
{
public:
Sys_var_charptr(const char *name_arg,
const char *comment, int flag_args, ptrdiff_t off, size_t size,
CMD_LINE getopt,
const char *def_val, 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) :
Sys_var_charptr_base(name_arg, comment, flag_args, off, size, getopt,
def_val, lock, binlog_status_arg,
on_check_func, on_update_func, substitute)
{
SYSVAR_ASSERT(scope() == GLOBAL);
SYSVAR_ASSERT(size == sizeof(char *));
}
bool session_update(THD *thd, set_var *var)
{
DBUG_ASSERT(FALSE);
return true;
}
void session_save_default(THD *thd, set_var *var)
{ DBUG_ASSERT(FALSE); }
};
class Sys_var_charptr_fscs: public Sys_var_charptr
{
using Sys_var_charptr::Sys_var_charptr;
@ -637,23 +634,22 @@ public:
}
};
#ifndef EMBEDDED_LIBRARY
class Sys_var_sesvartrack: public Sys_var_charptr_base
class Sys_var_sesvartrack: public Sys_var_charptr
{
public:
Sys_var_sesvartrack(const char *name_arg,
const char *comment,
CMD_LINE getopt,
const char *def_val, PolyLock *lock= 0) :
Sys_var_charptr_base(name_arg, comment,
SESSION_VAR(session_track_system_variables),
getopt, def_val, lock,
VARIABLE_NOT_IN_BINLOG, 0, 0, 0)
Sys_var_charptr(name_arg, comment,
SESSION_VAR(session_track_system_variables),
getopt, def_val, lock,
VARIABLE_NOT_IN_BINLOG, 0, 0, 0)
{}
bool do_check(THD *thd, set_var *var)
{
if (Sys_var_charptr_base::do_check(thd, var) ||
if (Sys_var_charptr::do_string_check(thd, var, charset(thd)) ||
sysvartrack_validate_value(thd, var->save_result.string_value.str,
var->save_result.string_value.length))
return TRUE;
@ -661,7 +657,7 @@ public:
}
bool global_update(THD *thd, set_var *var)
{
char *new_val= global_update_prepare(thd, var);
char *new_val= update_prepare(var, MYF(MY_WME));
if (new_val)
{
if (sysvartrack_global_update(thd, new_val,
@ -858,7 +854,19 @@ public:
Backing store: LEX_CSTRING
@note
Behaves exactly as Sys_var_charptr, only the backing store is different.
Behaves exactly as Sys_var_charptr, only the backing store is
different.
Note that for global variables handle_options() only sets the
pointer, whereas the length must be updated manually to match, which
is done in mysqld.cc. See e.g. opt_init_connect. TODO: it should be
done automatically when we'll have more Sys_var_lexstring variables
to justify it. Maybe some kind of a loop over all variables, like
sys_var_end() in set_var.cc?
Note that as a subclass of Sys_var_charptr, the memory management
for session Sys_var_lexstring's is manual too, see notes of
Sys_var_charptr and for example default_master_connection.
*/
class Sys_var_lexstring: public Sys_var_charptr
{
@ -886,88 +894,15 @@ public:
global_var(LEX_CSTRING).length= var->save_result.string_value.length;
return false;
}
};
/*
A LEX_CSTRING stored only in thd->variables
Only to be used for small buffers
*/
class Sys_var_session_lexstring: public sys_var
{
size_t max_length;
public:
Sys_var_session_lexstring(const char *name_arg,
const char *comment, int flag_args,
ptrdiff_t off, size_t size, CMD_LINE getopt,
const char *def_val, size_t max_length_arg,
on_check_function on_check_func=0,
on_update_function on_update_func=0)
: sys_var(&all_sys_vars, name_arg, comment, flag_args, off, getopt.id,
getopt.arg_type, SHOW_CHAR, (intptr)def_val,
0, VARIABLE_NOT_IN_BINLOG, on_check_func, on_update_func,
0),max_length(max_length_arg)
{
option.var_type|= GET_STR;
SYSVAR_ASSERT(scope() == ONLY_SESSION)
*const_cast<SHOW_TYPE*>(&show_val_type)= SHOW_LEX_STRING;
}
bool do_check(THD *thd, set_var *var)
{
char buff[STRING_BUFFER_USUAL_SIZE];
String str(buff, sizeof(buff), system_charset_info), *res;
if (!(res=var->value->val_str(&str)))
{
var->save_result.string_value.str= 0; /* NULL */
var->save_result.string_value.length= 0;
}
else
{
if (res->length() > max_length)
{
my_error(ER_WRONG_STRING_LENGTH, MYF(0),
res->ptr(), name.str, (int) max_length);
return true;
}
var->save_result.string_value.str= thd->strmake(res->ptr(),
res->length());
var->save_result.string_value.length= res->length();
}
return false;
}
bool session_update(THD *thd, set_var *var)
{
LEX_CSTRING *tmp= &session_var(thd, LEX_CSTRING);
tmp->length= var->save_result.string_value.length;
/* Store as \0 terminated string (just to be safe) */
strmake((char*) tmp->str, var->save_result.string_value.str, tmp->length);
if (Sys_var_charptr::session_update(thd, var))
return true;
session_var(thd, LEX_CSTRING).length= var->save_result.string_value.length;
return false;
}
bool global_update(THD *thd, set_var *var)
{
DBUG_ASSERT(FALSE);
return false;
}
void session_save_default(THD *thd, set_var *var)
{
char *ptr= (char*)(intptr)option.def_value;
var->save_result.string_value.str= ptr;
var->save_result.string_value.length= strlen(ptr);
}
void global_save_default(THD *thd, set_var *var)
{
DBUG_ASSERT(FALSE);
}
const uchar *global_value_ptr(THD *thd, const LEX_CSTRING *base) const
{
DBUG_ASSERT(FALSE);
return NULL;
}
};
#ifndef DBUG_OFF
/**
@@session.debug_dbug and @@global.debug_dbug variables.