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Bug#39955 SELECT on INFORMATION_SCHEMA.GLOBAL_VARIABLES takes too long

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VARIABLE_VALUE field is decreased to 1024 symbols.
(affected I_S tables: GLOBAL_VARIABLES, SESSION_VARIABLES,
 GLOBAL_STATUS, SESSION_STATUS).
The only variable which can be longer than 1024 is
init_connect. The variable will be truncated with warning.
Additional fix:
Added where condition filter which speed up queries which
have where condition with expressions which use VARIABLE_NAME
field.
This commit is contained in:
Sergey Glukhov 2008-11-13 16:09:11 +04:00
parent 45deeca2dd
commit 3fa2673f19
5 changed files with 116 additions and 29 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

47
mysql-test/r/information_schema.result
View File

@ -1651,4 +1651,51 @@ id select_type table type possible_keys key key_len ref rows Extra
explain select count(*) from information_schema.views;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE views ALL NULL NULL NULL NULL NULL Open_frm_only; Scanned all databases
set global init_connect="drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;";
select * from information_schema.global_variables where variable_name='init_connect';
VARIABLE_NAME VARIABLE_VALUE
INIT_CONNECT drop table if exists t1;drop table if exists t1;
drop table if exists t1;drop table if exists t1;
drop table if exists t1;drop table if exists t1;
drop table if exists t1;drop table if exists t1;
drop table if exists t1;drop table if exists t1;
drop table if exists t1;drop table if exists t1;
drop table if exists t1;drop table if exists t1;
drop table if exists t1;drop table if exists t1;
drop table if exists t1;drop table if exists t1;
drop table if exists t1;drop table if exists t1;
drop table if exists t1;drop table if exists t1;
drop table if exists t1;drop table if exists t1;
drop table if exists t1;drop table if exists t1;
drop table if exists t1;drop table if exists t1;
drop table if exists t1;drop table if exists t1;
drop table if exists t1;drop table if exists t1;
drop table if exists t1;drop table if exists t1;
drop table if exists t1;drop table if exists t1;
drop table if exists t1;drop table if exists t1;
drop table if exists t1;drop table if exists t1;
drop table if exists t1;drop table if exists
Warnings:
Warning 1265 Data truncated for column 'VARIABLE_VALUE' at row 1
set global init_connect="";
End of 5.1 tests.

6
mysql-test/r/show_check.result
View File

@ -100,19 +100,19 @@ drop table t1;
show variables like "wait_timeout%";
Catalog Database Table Table_alias Column Column_alias Type Length Max length Is_null Flags Decimals Charsetnr
def VARIABLES VARIABLE_NAME Variable_name 253 64 12 N 1 0 8
def VARIABLES VARIABLE_VALUE Value 253 20480 5 Y 0 0 8
def VARIABLES VARIABLE_VALUE Value 253 1024 5 Y 0 0 8
Variable_name Value
wait_timeout 28800
show variables like "WAIT_timeout%";
Catalog Database Table Table_alias Column Column_alias Type Length Max length Is_null Flags Decimals Charsetnr
def VARIABLES VARIABLE_NAME Variable_name 253 64 12 N 1 0 8
def VARIABLES VARIABLE_VALUE Value 253 20480 5 Y 0 0 8
def VARIABLES VARIABLE_VALUE Value 253 1024 5 Y 0 0 8
Variable_name Value
wait_timeout 28800
show variables like "this_doesn't_exists%";
Catalog Database Table Table_alias Column Column_alias Type Length Max length Is_null Flags Decimals Charsetnr
def VARIABLES VARIABLE_NAME Variable_name 253 64 0 N 1 0 8
def VARIABLES VARIABLE_VALUE Value 253 20480 0 Y 0 0 8
def VARIABLES VARIABLE_VALUE Value 253 1024 0 Y 0 0 8
Variable_name Value
show table status from test like "this_doesn't_exists%";
Catalog Database Table Table_alias Column Column_alias Type Length Max length Is_null Flags Decimals Charsetnr

16
mysql-test/suite/funcs_1/r/is_columns_is.result
View File

@ -110,9 +110,9 @@ NULL information_schema FILES UPDATE_COUNT 13 NULL YES bigint NULL NULL 19 0 NUL
NULL information_schema FILES UPDATE_TIME 34 NULL YES datetime NULL NULL NULL NULL NULL NULL datetime select
NULL information_schema FILES VERSION 25 NULL YES bigint NULL NULL 19 0 NULL NULL bigint(21) unsigned select
NULL information_schema GLOBAL_STATUS VARIABLE_NAME 1 NO varchar 64 192 NULL NULL utf8 utf8_general_ci varchar(64) select
NULL information_schema GLOBAL_STATUS VARIABLE_VALUE 2 NULL YES varchar 20480 61440 NULL NULL utf8 utf8_general_ci varchar(20480) select
NULL information_schema GLOBAL_STATUS VARIABLE_VALUE 2 NULL YES varchar 1024 3072 NULL NULL utf8 utf8_general_ci varchar(1024) select
NULL information_schema GLOBAL_VARIABLES VARIABLE_NAME 1 NO varchar 64 192 NULL NULL utf8 utf8_general_ci varchar(64) select
NULL information_schema GLOBAL_VARIABLES VARIABLE_VALUE 2 NULL YES varchar 20480 61440 NULL NULL utf8 utf8_general_ci varchar(20480) select
NULL information_schema GLOBAL_VARIABLES VARIABLE_VALUE 2 NULL YES varchar 1024 3072 NULL NULL utf8 utf8_general_ci varchar(1024) select
NULL information_schema KEY_COLUMN_USAGE COLUMN_NAME 7 NO varchar 64 192 NULL NULL utf8 utf8_general_ci varchar(64) select
NULL information_schema KEY_COLUMN_USAGE CONSTRAINT_CATALOG 1 NULL YES varchar 512 1536 NULL NULL utf8 utf8_general_ci varchar(512) select
NULL information_schema KEY_COLUMN_USAGE CONSTRAINT_NAME 3 NO varchar 64 192 NULL NULL utf8 utf8_general_ci varchar(64) select
@ -213,9 +213,9 @@ NULL information_schema SCHEMA_PRIVILEGES PRIVILEGE_TYPE 4 NO varchar 64 192 NU
NULL information_schema SCHEMA_PRIVILEGES TABLE_CATALOG 2 NULL YES varchar 512 1536 NULL NULL utf8 utf8_general_ci varchar(512) select
NULL information_schema SCHEMA_PRIVILEGES TABLE_SCHEMA 3 NO varchar 64 192 NULL NULL utf8 utf8_general_ci varchar(64) select
NULL information_schema SESSION_STATUS VARIABLE_NAME 1 NO varchar 64 192 NULL NULL utf8 utf8_general_ci varchar(64) select
NULL information_schema SESSION_STATUS VARIABLE_VALUE 2 NULL YES varchar 20480 61440 NULL NULL utf8 utf8_general_ci varchar(20480) select
NULL information_schema SESSION_STATUS VARIABLE_VALUE 2 NULL YES varchar 1024 3072 NULL NULL utf8 utf8_general_ci varchar(1024) select
NULL information_schema SESSION_VARIABLES VARIABLE_NAME 1 NO varchar 64 192 NULL NULL utf8 utf8_general_ci varchar(64) select
NULL information_schema SESSION_VARIABLES VARIABLE_VALUE 2 NULL YES varchar 20480 61440 NULL NULL utf8 utf8_general_ci varchar(20480) select
NULL information_schema SESSION_VARIABLES VARIABLE_VALUE 2 NULL YES varchar 1024 3072 NULL NULL utf8 utf8_general_ci varchar(1024) select
NULL information_schema STATISTICS CARDINALITY 10 NULL YES bigint NULL NULL 19 0 NULL NULL bigint(21) select
NULL information_schema STATISTICS COLLATION 9 NULL YES varchar 1 3 NULL NULL utf8 utf8_general_ci varchar(1) select
NULL information_schema STATISTICS COLUMN_NAME 8 NO varchar 64 192 NULL NULL utf8 utf8_general_ci varchar(64) select
@ -464,9 +464,9 @@ NULL information_schema FILES CHECKSUM bigint NULL NULL NULL NULL bigint(21) uns
3.0000 information_schema FILES STATUS varchar 20 60 utf8 utf8_general_ci varchar(20)
3.0000 information_schema FILES EXTRA varchar 255 765 utf8 utf8_general_ci varchar(255)
3.0000 information_schema GLOBAL_STATUS VARIABLE_NAME varchar 64 192 utf8 utf8_general_ci varchar(64)
3.0000 information_schema GLOBAL_STATUS VARIABLE_VALUE varchar 20480 61440 utf8 utf8_general_ci varchar(20480)
3.0000 information_schema GLOBAL_STATUS VARIABLE_VALUE varchar 1024 3072 utf8 utf8_general_ci varchar(1024)
3.0000 information_schema GLOBAL_VARIABLES VARIABLE_NAME varchar 64 192 utf8 utf8_general_ci varchar(64)
3.0000 information_schema GLOBAL_VARIABLES VARIABLE_VALUE varchar 20480 61440 utf8 utf8_general_ci varchar(20480)
3.0000 information_schema GLOBAL_VARIABLES VARIABLE_VALUE varchar 1024 3072 utf8 utf8_general_ci varchar(1024)
3.0000 information_schema KEY_COLUMN_USAGE CONSTRAINT_CATALOG varchar 512 1536 utf8 utf8_general_ci varchar(512)
3.0000 information_schema KEY_COLUMN_USAGE CONSTRAINT_SCHEMA varchar 64 192 utf8 utf8_general_ci varchar(64)
3.0000 information_schema KEY_COLUMN_USAGE CONSTRAINT_NAME varchar 64 192 utf8 utf8_general_ci varchar(64)
@ -567,9 +567,9 @@ NULL information_schema ROUTINES LAST_ALTERED datetime NULL NULL NULL NULL datet
3.0000 information_schema SCHEMA_PRIVILEGES PRIVILEGE_TYPE varchar 64 192 utf8 utf8_general_ci varchar(64)
3.0000 information_schema SCHEMA_PRIVILEGES IS_GRANTABLE varchar 3 9 utf8 utf8_general_ci varchar(3)
3.0000 information_schema SESSION_STATUS VARIABLE_NAME varchar 64 192 utf8 utf8_general_ci varchar(64)
3.0000 information_schema SESSION_STATUS VARIABLE_VALUE varchar 20480 61440 utf8 utf8_general_ci varchar(20480)
3.0000 information_schema SESSION_STATUS VARIABLE_VALUE varchar 1024 3072 utf8 utf8_general_ci varchar(1024)
3.0000 information_schema SESSION_VARIABLES VARIABLE_NAME varchar 64 192 utf8 utf8_general_ci varchar(64)
3.0000 information_schema SESSION_VARIABLES VARIABLE_VALUE varchar 20480 61440 utf8 utf8_general_ci varchar(20480)
3.0000 information_schema SESSION_VARIABLES VARIABLE_VALUE varchar 1024 3072 utf8 utf8_general_ci varchar(1024)
3.0000 information_schema STATISTICS TABLE_CATALOG varchar 512 1536 utf8 utf8_general_ci varchar(512)
3.0000 information_schema STATISTICS TABLE_SCHEMA varchar 64 192 utf8 utf8_general_ci varchar(64)
3.0000 information_schema STATISTICS TABLE_NAME varchar 64 192 utf8 utf8_general_ci varchar(64)

27
mysql-test/t/information_schema.test
View File

@ -1346,4 +1346,31 @@ explain select count(*) from information_schema.tables;
explain select count(*) from information_schema.columns;
explain select count(*) from information_schema.views;
#
# Bug#39955 SELECT on INFORMATION_SCHEMA.GLOBAL_VARIABLES takes too long
#
set global init_connect="drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;\
drop table if exists t1;drop table if exists t1;";
select * from information_schema.global_variables where variable_name='init_connect';
set global init_connect="";
--echo End of 5.1 tests.

49
sql/sql_show.cc
View File

@ -83,6 +83,7 @@ static void store_key_options(THD *thd, String *packet, TABLE *table,
static void
append_algorithm(TABLE_LIST *table, String *buff);
static COND * make_cond_for_info_schema(COND *cond, TABLE_LIST *table);
/***************************************************************************
** List all table types supported
@ -2072,7 +2073,8 @@ static bool show_status_array(THD *thd, const char *wild,
enum enum_var_type value_type,
struct system_status_var *status_var,
const char *prefix, TABLE *table,
bool ucase_names)
bool ucase_names,
COND *cond)
{
MY_ALIGNED_BYTE_ARRAY(buff_data, SHOW_VAR_FUNC_BUFF_SIZE, long);
char * const buff= (char *) &buff_data;
@ -2082,8 +2084,12 @@ static bool show_status_array(THD *thd, const char *wild,
int len;
LEX_STRING null_lex_str;
SHOW_VAR tmp, *var;
COND *partial_cond= 0;
enum_check_fields save_count_cuted_fields= thd->count_cuted_fields;
bool res= FALSE;
DBUG_ENTER("show_status_array");
thd->count_cuted_fields= CHECK_FIELD_WARN;
null_lex_str.str= 0; // For sys_var->value_ptr()
null_lex_str.length= 0;
@ -2091,6 +2097,7 @@ static bool show_status_array(THD *thd, const char *wild,
if (*prefix)
*prefix_end++= '_';
len=name_buffer + sizeof(name_buffer) - prefix_end;
partial_cond= make_cond_for_info_schema(cond, table->pos_in_table_list);
for (; variables->name; variables++)
{
@ -2099,6 +2106,9 @@ static bool show_status_array(THD *thd, const char *wild,
if (ucase_names)
make_upper(name_buffer);
restore_record(table, s->default_values);
table->field[0]->store(name_buffer, strlen(name_buffer),
system_charset_info);
/*
if var->type is SHOW_FUNC, call the function.
Repeat as necessary, if new var is again SHOW_FUNC
@ -2110,12 +2120,13 @@ static bool show_status_array(THD *thd, const char *wild,
if (show_type == SHOW_ARRAY)
{
show_status_array(thd, wild, (SHOW_VAR *) var->value, value_type,
status_var, name_buffer, table, ucase_names);
status_var, name_buffer, table, ucase_names, partial_cond);
}
else
{
if (!(wild && wild[0] && wild_case_compare(system_charset_info,
name_buffer, wild)))
name_buffer, wild)) &&
(!partial_cond || partial_cond->val_int()))
{
char *value=var->value;
const char *pos, *end; // We assign a lot of const's
@ -2202,21 +2213,23 @@ static bool show_status_array(THD *thd, const char *wild,
DBUG_ASSERT(0);
break;
}
restore_record(table, s->default_values);
table->field[0]->store(name_buffer, strlen(name_buffer),
system_charset_info);
table->field[1]->store(pos, (uint32) (end - pos), system_charset_info);
thd->count_cuted_fields= CHECK_FIELD_IGNORE;
table->field[1]->set_notnull();
pthread_mutex_unlock(&LOCK_global_system_variables);
if (schema_table_store_record(thd, table))
DBUG_RETURN(TRUE);
{
res= TRUE;
goto end;
}
}
}
}
DBUG_RETURN(FALSE);
end:
thd->count_cuted_fields= save_count_cuted_fields;
DBUG_RETURN(res);
}
@ -5244,7 +5257,7 @@ int fill_variables(THD *thd, TABLE_LIST *tables, COND *cond)
rw_rdlock(&LOCK_system_variables_hash);
res= show_status_array(thd, wild, enumerate_sys_vars(thd, sorted_vars),
option_type, NULL, "", tables->table, upper_case_names);
option_type, NULL, "", tables->table, upper_case_names, cond);
rw_unlock(&LOCK_system_variables_hash);
DBUG_RETURN(res);
}
@ -5287,7 +5300,7 @@ int fill_status(THD *thd, TABLE_LIST *tables, COND *cond)
res= show_status_array(thd, wild,
(SHOW_VAR *)all_status_vars.buffer,
option_type, tmp1, "", tables->table,
upper_case_names);
upper_case_names, cond);
pthread_mutex_unlock(&LOCK_status);
DBUG_RETURN(res);
}
@ -6456,7 +6469,7 @@ ST_FIELD_INFO variables_fields_info[]=
{
{"VARIABLE_NAME", 64, MYSQL_TYPE_STRING, 0, 0, "Variable_name",
SKIP_OPEN_TABLE},
{"VARIABLE_VALUE", 20480, MYSQL_TYPE_STRING, 0, 1, "Value", SKIP_OPEN_TABLE},
{"VARIABLE_VALUE", 1024, MYSQL_TYPE_STRING, 0, 1, "Value", SKIP_OPEN_TABLE},
{0, 0, MYSQL_TYPE_STRING, 0, 0, 0, SKIP_OPEN_TABLE}
};
@ -6615,9 +6628,9 @@ ST_SCHEMA_TABLE schema_tables[]=
{"FILES", files_fields_info, create_schema_table,
fill_schema_files, 0, 0, -1, -1, 0, 0},
{"GLOBAL_STATUS", variables_fields_info, create_schema_table,
fill_status, make_old_format, 0, -1, -1, 0, 0},
fill_status, make_old_format, 0, 0, -1, 0, 0},
{"GLOBAL_VARIABLES", variables_fields_info, create_schema_table,
fill_variables, make_old_format, 0, -1, -1, 0, 0},
fill_variables, make_old_format, 0, 0, -1, 0, 0},
{"KEY_COLUMN_USAGE", key_column_usage_fields_info, create_schema_table,
get_all_tables, 0, get_schema_key_column_usage_record, 4, 5, 0,
OPEN_TABLE_ONLY},
@ -6642,14 +6655,14 @@ ST_SCHEMA_TABLE schema_tables[]=
{"SCHEMA_PRIVILEGES", schema_privileges_fields_info, create_schema_table,
fill_schema_schema_privileges, 0, 0, -1, -1, 0, 0},
{"SESSION_STATUS", variables_fields_info, create_schema_table,
fill_status, make_old_format, 0, -1, -1, 0, 0},
fill_status, make_old_format, 0, 0, -1, 0, 0},
{"SESSION_VARIABLES", variables_fields_info, create_schema_table,
fill_variables, make_old_format, 0, -1, -1, 0, 0},
fill_variables, make_old_format, 0, 0, -1, 0, 0},
{"STATISTICS", stat_fields_info, create_schema_table,
get_all_tables, make_old_format, get_schema_stat_record, 1, 2, 0,
OPEN_TABLE_ONLY|OPTIMIZE_I_S_TABLE},
{"STATUS", variables_fields_info, create_schema_table, fill_status,
make_old_format, 0, -1, -1, 1, 0},
make_old_format, 0, 0, -1, 1, 0},
{"TABLES", tables_fields_info, create_schema_table,
get_all_tables, make_old_format, get_schema_tables_record, 1, 2, 0,
OPTIMIZE_I_S_TABLE},
@ -6665,7 +6678,7 @@ ST_SCHEMA_TABLE schema_tables[]=
{"USER_PRIVILEGES", user_privileges_fields_info, create_schema_table,
fill_schema_user_privileges, 0, 0, -1, -1, 0, 0},
{"VARIABLES", variables_fields_info, create_schema_table, fill_variables,
make_old_format, 0, -1, -1, 1, 0},
make_old_format, 0, 0, -1, 1, 0},
{"VIEWS", view_fields_info, create_schema_table,
get_all_tables, 0, get_schema_views_record, 1, 2, 0,
OPEN_VIEW_ONLY|OPTIMIZE_I_S_TABLE},