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mariadb/mysql-test/main/variables.result
Monty e600f9aebb MDEV-35750 Change MEM_ROOT allocation sizes to reduse calls to malloc() and avoid memory fragmentation 
This commit updates default memory allocations size used with MEM_ROOT
objects to minimize the number of calls to malloc().

Changes:
- Updated MEM_ROOT block sizes in sql_const.h
- Updated MALLOC_OVERHEAD to also take into account the extra memory
  allocated by my_malloc()
- Updated init_alloc_root() to only take MALLOC_OVERHEAD into account as
  buffer size, not MALLOC_OVERHEAD + sizeof(USED_MEM).
- Reset mem_root->first_block_usage if and only if first block was used.
- Increase MEM_ROOT buffers sized used by my_load_defaults, plugin_init,
  Create_tmp_table, allocate_table_share, TABLE and TABLE_SHARE.
  This decreases number of malloc calls during queries.
- Use a small buffer for THD->main_mem_root in THD::THD. This avoids
  multiple malloc() call for new connections.

I tried the above changes on a complex select query with 12 tables.
The following shows the number of extra allocations that where used
to increase the size of the MEM_ROOT buffers.

Original code:
- Connection to MariaDB:   9 allocations
- First query run:       146 allocations
- Second query run:       24 allocations

Max memory allocated for thd when using with heap table:  61,262,408
Max memory allocated for thd when using Aria tmp table:      419,464

After changes:
Connection to MariaDB:     0 allocations
- First run:              25 allocations
- Second run:              7 allocations

Max memory allocated for thd when using with heap table:  61,347,424
Max memory allocated for thd when using Aria table:          529,168

The new code uses slightly more memory, but avoids memory fragmentation
and is slightly faster thanks to much fewer calls to malloc().

Reviewed-by: Sergei Golubchik <serg@mariadb.org>
2025-01-05 16:40:11 +02:00

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drop table if exists t1,t2;
set @my_binlog_cache_size =@@global.binlog_cache_size;
set @my_connect_timeout =@@global.connect_timeout;
set @my_delayed_insert_timeout =@@global.delayed_insert_timeout;
set @my_delayed_queue_size =@@global.delayed_queue_size;
set @my_flush =@@global.flush;
set @my_flush_time =@@global.flush_time;
set @my_key_buffer_size =@@global.key_buffer_size;
set @my_max_binlog_cache_size =@@global.max_binlog_cache_size;
set @my_max_binlog_size =@@global.max_binlog_size;
set @my_max_connect_errors =@@global.max_connect_errors;
set @my_max_connections =@@global.max_connections;
set @my_max_delayed_threads =@@global.max_delayed_threads;
set @my_max_heap_table_size =@@global.max_heap_table_size;
set @my_max_insert_delayed_threads=@@global.max_insert_delayed_threads;
set @my_max_join_size =@@global.max_join_size;
set @my_max_user_connections =@@global.max_user_connections;
set @my_myisam_data_pointer_size =@@global.myisam_data_pointer_size;
set @my_myisam_max_sort_file_size =@@global.myisam_max_sort_file_size;
set @my_net_buffer_length =@@global.net_buffer_length;
set @my_net_write_timeout =@@global.net_write_timeout;
set @my_net_read_timeout =@@global.net_read_timeout;
set @my_server_id =@@global.server_id;
set @my_slow_launch_time =@@global.slow_launch_time;
set @my_storage_engine =@@global.default_storage_engine;
set @my_thread_cache_size =@@global.thread_cache_size;
set @my_max_allowed_packet =@@global.max_allowed_packet;
set @my_delay_key_write =@@global.delay_key_write;
set @my_join_buffer_size =@@global.join_buffer_size;
set @my_log_warnings =@@global.log_warnings;
set @my_local_infile =@@global.local_infile;
set @`test`=1;
select @test, @`test`, @TEST, @`TEST`, @"teSt";
@test @`test` @TEST @`TEST` @"teSt"
1 1 1 1 1
set @TEST=2;
select @test, @`test`, @TEST, @`TEST`, @"teSt";
@test @`test` @TEST @`TEST` @"teSt"
2 2 2 2 2
set @"tEST"=3;
select @test, @`test`, @TEST, @`TEST`, @"teSt";
@test @`test` @TEST @`TEST` @"teSt"
3 3 3 3 3
set @`TeST`=4;
select @test, @`test`, @TEST, @`TEST`, @"teSt";
@test @`test` @TEST @`TEST` @"teSt"
4 4 4 4 4
select @`teST`:=5;
@`teST`:=5
5
select @test, @`test`, @TEST, @`TEST`, @"teSt";
@test @`test` @TEST @`TEST` @"teSt"
5 5 5 5 5
set @select=2,@t5=1.23456;
select @`select`,@not_used;
@`select` @not_used
2 NULL
set @test_int=10,@test_double=1e-10,@test_string="abcdeghi",@test_string2="abcdefghij",@select=NULL;
select @test_int,@test_double,@test_string,@test_string2,@select;
@test_int @test_double @test_string @test_string2 @select
10 0.0000000001 abcdeghi abcdefghij NULL
set @test_int="hello",@test_double="hello",@test_string="hello",@test_string2="hello";
select @test_int,@test_double,@test_string,@test_string2;
@test_int @test_double @test_string @test_string2
hello hello hello hello
set @test_int="hellohello",@test_double="hellohello",@test_string="hellohello",@test_string2="hellohello";
select @test_int,@test_double,@test_string,@test_string2;
@test_int @test_double @test_string @test_string2
hellohello hellohello hellohello hellohello
set @test_int=null,@test_double=null,@test_string=null,@test_string2=null;
select @test_int,@test_double,@test_string,@test_string2;
@test_int @test_double @test_string @test_string2
NULL NULL NULL NULL
select @t1:=(@t2:=1)+@t3:=4,@t1,@t2,@t3;
@t1:=(@t2:=1)+@t3:=4 @t1 @t2 @t3
5 5 1 4
explain extended select @t1:=(@t2:=1)+@t3:=4,@t1,@t2,@t3;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL No tables used
Warnings:
Note 1003 select @t1:=(@t2:=1) + (@t3:=4) AS `@t1:=(@t2:=1)+@t3:=4`,@`t1` AS `@t1`,@`t2` AS `@t2`,@`t3` AS `@t3`
select @t5;
@t5
1.23456
CREATE TABLE t1 (c_id INT(4) NOT NULL, c_name CHAR(20), c_country CHAR(3), PRIMARY KEY(c_id));
INSERT INTO t1 VALUES (1,'Bozo','USA'),(2,'Ronald','USA'),(3,'Kinko','IRE'),(4,'Mr. Floppy','GB');
SELECT @min_cid:=min(c_id), @max_cid:=max(c_id) from t1;
@min_cid:=min(c_id) @max_cid:=max(c_id)
1 4
SELECT * FROM t1 WHERE c_id=@min_cid OR c_id=@max_cid;
c_id c_name c_country
1 Bozo USA
4 Mr. Floppy GB
SELECT * FROM t1 WHERE c_id=@min_cid OR c_id=@max_cid OR c_id=666;
c_id c_name c_country
1 Bozo USA
4 Mr. Floppy GB
ALTER TABLE t1 DROP PRIMARY KEY;
select * from t1 where c_id=@min_cid OR c_id=@max_cid;
c_id c_name c_country
1 Bozo USA
4 Mr. Floppy GB
drop table t1;
set GLOBAL max_join_size=10;
set max_join_size=100;
show variables like 'max_join_size';
Variable_name Value
max_join_size 100
select * from information_schema.session_variables where variable_name like 'max_join_size';
VARIABLE_NAME VARIABLE_VALUE
MAX_JOIN_SIZE 100
show global variables like 'max_join_size';
Variable_name Value
max_join_size 10
select * from information_schema.global_variables where variable_name like 'max_join_size';
VARIABLE_NAME VARIABLE_VALUE
MAX_JOIN_SIZE 10
set GLOBAL max_join_size=2000;
show global variables like 'max_join_size';
Variable_name Value
max_join_size 2000
select * from information_schema.global_variables where variable_name like 'max_join_size';
VARIABLE_NAME VARIABLE_VALUE
MAX_JOIN_SIZE 2000
set max_join_size=DEFAULT;
show variables like 'max_join_size';
Variable_name Value
max_join_size 2000
select * from information_schema.session_variables where variable_name like 'max_join_size';
VARIABLE_NAME VARIABLE_VALUE
MAX_JOIN_SIZE 2000
set GLOBAL max_join_size=DEFAULT;
show global variables like 'max_join_size';
Variable_name Value
max_join_size HA_POS_ERROR
select * from information_schema.global_variables where variable_name like 'max_join_size';
VARIABLE_NAME VARIABLE_VALUE
MAX_JOIN_SIZE HA_POS_ERROR
set @@max_join_size=1000, @@global.max_join_size=2000;
select @@local.max_join_size, @@global.max_join_size;
@@local.max_join_size @@global.max_join_size
1000 2000
select @@identity, length(@@version)>0;
@@identity length(@@version)>0
0 1
select @@VERSION=version();
@@VERSION=version()
1
select last_insert_id(345);
last_insert_id(345)
345
explain extended select last_insert_id(345);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL No tables used
Warnings:
Note 1003 select last_insert_id(345) AS `last_insert_id(345)`
select @@IDENTITY,last_insert_id(), @@identity;
@@IDENTITY last_insert_id() @@identity
345 345 345
explain extended select @@IDENTITY,last_insert_id(), @@identity;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL No tables used
Warnings:
Note 1003 select @@IDENTITY AS `@@IDENTITY`,last_insert_id() AS `last_insert_id()`,@@identity AS `@@identity`
set global concurrent_insert=2;
show variables like 'concurrent_insert';
Variable_name Value
concurrent_insert ALWAYS
select * from information_schema.session_variables where variable_name like 'concurrent_insert';
VARIABLE_NAME VARIABLE_VALUE
CONCURRENT_INSERT ALWAYS
set global concurrent_insert=1;
show variables like 'concurrent_insert';
Variable_name Value
concurrent_insert AUTO
select * from information_schema.session_variables where variable_name like 'concurrent_insert';
VARIABLE_NAME VARIABLE_VALUE
CONCURRENT_INSERT AUTO
set global concurrent_insert=0;
show variables like 'concurrent_insert';
Variable_name Value
concurrent_insert NEVER
select * from information_schema.session_variables where variable_name like 'concurrent_insert';
VARIABLE_NAME VARIABLE_VALUE
CONCURRENT_INSERT NEVER
set global concurrent_insert=DEFAULT;
select @@concurrent_insert;
@@concurrent_insert
AUTO
set default_storage_engine=MYISAM, default_storage_engine="HEAP", global default_storage_engine="MERGE";
show local variables like 'default_storage_engine';
Variable_name Value
default_storage_engine MEMORY
select * from information_schema.session_variables where variable_name like 'default_storage_engine';
VARIABLE_NAME VARIABLE_VALUE
DEFAULT_STORAGE_ENGINE MEMORY
show global variables like 'default_storage_engine';
Variable_name Value
default_storage_engine MRG_MyISAM
select * from information_schema.global_variables where variable_name like 'default_storage_engine';
VARIABLE_NAME VARIABLE_VALUE
DEFAULT_STORAGE_ENGINE MRG_MyISAM
set GLOBAL myisam_max_sort_file_size=2000000;
Warnings:
Warning 1292 Truncated incorrect myisam_max_sort_file_size value: '2000000'
show global variables like 'myisam_max_sort_file_size';
Variable_name Value
myisam_max_sort_file_size 1048576
select * from information_schema.global_variables where variable_name like 'myisam_max_sort_file_size';
VARIABLE_NAME VARIABLE_VALUE
MYISAM_MAX_SORT_FILE_SIZE 1048576
set GLOBAL myisam_max_sort_file_size=default;
show global variables like 'myisam_max_sort_file_size';
Variable_name Value
myisam_max_sort_file_size FILE_SIZE
select * from information_schema.global_variables where variable_name like 'myisam_max_sort_file_size';
VARIABLE_NAME VARIABLE_VALUE
MYISAM_MAX_SORT_FILE_SIZE FILE_SIZE
set global net_retry_count=10, session net_retry_count=10;
set global net_buffer_length=1024, net_write_timeout=200, net_read_timeout=300;
show global variables like 'net_%';
Variable_name Value
net_buffer_length 1024
net_read_timeout 300
net_retry_count 10
net_write_timeout 200
select * from information_schema.global_variables where variable_name like 'net_%' order by 1;
VARIABLE_NAME VARIABLE_VALUE
NET_BUFFER_LENGTH 1024
NET_READ_TIMEOUT 300
NET_RETRY_COUNT 10
NET_WRITE_TIMEOUT 200
show session variables like 'net_%';
Variable_name Value
net_buffer_length 16384
net_read_timeout 30
net_retry_count 10
net_write_timeout 60
select * from information_schema.session_variables where variable_name like 'net_%' order by 1;
VARIABLE_NAME VARIABLE_VALUE
NET_BUFFER_LENGTH 16384
NET_READ_TIMEOUT 30
NET_RETRY_COUNT 10
NET_WRITE_TIMEOUT 60
set global net_buffer_length=8000, global net_read_timeout=900, net_write_timeout=1000;
Warnings:
Warning 1292 Truncated incorrect net_buffer_length value: '8000'
show global variables like 'net_%';
Variable_name Value
net_buffer_length 7168
net_read_timeout 900
net_retry_count 10
net_write_timeout 1000
select * from information_schema.global_variables where variable_name like 'net_%' order by 1;
VARIABLE_NAME VARIABLE_VALUE
NET_BUFFER_LENGTH 7168
NET_READ_TIMEOUT 900
NET_RETRY_COUNT 10
NET_WRITE_TIMEOUT 1000
set global net_buffer_length=1;
Warnings:
Warning 1292 Truncated incorrect net_buffer_length value: '1'
show global variables like 'net_buffer_length';
Variable_name Value
net_buffer_length 1024
select * from information_schema.global_variables where variable_name like 'net_buffer_length';
VARIABLE_NAME VARIABLE_VALUE
NET_BUFFER_LENGTH 1024
set global net_buffer_length=2000000000;
Warnings:
Warning 1292 Truncated incorrect net_buffer_length value: '2000000000'
show global variables like 'net_buffer_length';
Variable_name Value
net_buffer_length 1048576
select * from information_schema.global_variables where variable_name like 'net_buffer_length';
VARIABLE_NAME VARIABLE_VALUE
NET_BUFFER_LENGTH 1048576
set character set cp1251_koi8;
show variables like "character_set_client";
Variable_name Value
character_set_client cp1251
select * from information_schema.session_variables where variable_name like 'character_set_client';
VARIABLE_NAME VARIABLE_VALUE
CHARACTER_SET_CLIENT cp1251
select @@timestamp>0;
@@timestamp>0
1
set @@rand_seed1=10000000,@@rand_seed2=1000000;
select ROUND(RAND(),5);
ROUND(RAND(),5)
0.02887
==+ Testing %alloc% system variables +==
==+ NOTE: These values *must* be a multiple of 1024 +==
==+ Other values will be rounded down to nearest multiple +==
==+ Show initial values +==
SHOW VARIABLES WHERE variable_name IN ('range_alloc_block_size',
'query_alloc_block_size', 'query_prealloc_size',
'transaction_alloc_block_size', 'transaction_prealloc_size');
Variable_name Value
query_alloc_block_size 32768
query_prealloc_size 32768
range_alloc_block_size 4096
transaction_alloc_block_size 8192
transaction_prealloc_size 4096
==+ information_schema data +==
SELECT * FROM information_schema.session_variables
WHERE variable_name IN ('range_alloc_block_size',
'query_alloc_block_size', 'query_prealloc_size',
'transaction_alloc_block_size', 'transaction_prealloc_size') ORDER BY 1;
VARIABLE_NAME VARIABLE_VALUE
QUERY_ALLOC_BLOCK_SIZE 32768
QUERY_PREALLOC_SIZE 32768
RANGE_ALLOC_BLOCK_SIZE 4096
TRANSACTION_ALLOC_BLOCK_SIZE 8192
TRANSACTION_PREALLOC_SIZE 4096
Testing values that are multiples of 1024
set @@range_alloc_block_size=1024*15+1024;
set @@query_alloc_block_size=1024*15+1024*2;
set @@query_prealloc_size=1024*18-1024;
set @@transaction_alloc_block_size=1024*21-1024*1;
set @@transaction_prealloc_size=1024*21-2048;
==+ Check manipulated values ==+
select @@query_alloc_block_size;
@@query_alloc_block_size
17408
SHOW VARIABLES WHERE variable_name IN ('range_alloc_block_size',
'query_alloc_block_size', 'query_prealloc_size',
'transaction_alloc_block_size', 'transaction_prealloc_size');
Variable_name Value
query_alloc_block_size 17408
query_prealloc_size 17408
range_alloc_block_size 16384
transaction_alloc_block_size 20480
transaction_prealloc_size 19456
==+ information_schema data +==
SELECT * FROM information_schema.session_variables
WHERE variable_name IN ('range_alloc_block_size',
'query_alloc_block_size', 'query_prealloc_size',
'transaction_alloc_block_size', 'transaction_prealloc_size') ORDER BY 1;
VARIABLE_NAME VARIABLE_VALUE
QUERY_ALLOC_BLOCK_SIZE 17408
QUERY_PREALLOC_SIZE 17408
RANGE_ALLOC_BLOCK_SIZE 16384
TRANSACTION_ALLOC_BLOCK_SIZE 20480
TRANSACTION_PREALLOC_SIZE 19456
==+ Manipulate variable values +==
Testing values that are not 1024 multiples
set @@range_alloc_block_size=1024*16+1023;
Warnings:
Warning 1292 Truncated incorrect range_alloc_block_size value: '17407'
set @@query_alloc_block_size=1024*17+2;
Warnings:
Warning 1292 Truncated incorrect query_alloc_block_size value: '17410'
set @@query_prealloc_size=1024*18-1023;
Warnings:
Warning 1292 Truncated incorrect query_prealloc_size value: '17409'
set @@transaction_alloc_block_size=1024*20-1;
Warnings:
Warning 1292 Truncated incorrect transaction_alloc_block_size value: '20479'
set @@transaction_prealloc_size=1024*21-1;
Warnings:
Warning 1292 Truncated incorrect transaction_prealloc_size value: '21503'
==+ Check manipulated values ==+
SHOW VARIABLES WHERE variable_name IN ('range_alloc_block_size',
'query_alloc_block_size', 'query_prealloc_size',
'transaction_alloc_block_size', 'transaction_prealloc_size');
Variable_name Value
query_alloc_block_size 17408
query_prealloc_size 17408
range_alloc_block_size 16384
transaction_alloc_block_size 19456
transaction_prealloc_size 20480
==+ information_schema data +==
SELECT * FROM information_schema.session_variables
WHERE variable_name IN ('range_alloc_block_size',
'query_alloc_block_size', 'query_prealloc_size',
'transaction_alloc_block_size', 'transaction_prealloc_size') ORDER BY 1;
VARIABLE_NAME VARIABLE_VALUE
QUERY_ALLOC_BLOCK_SIZE 17408
QUERY_PREALLOC_SIZE 17408
RANGE_ALLOC_BLOCK_SIZE 16384
TRANSACTION_ALLOC_BLOCK_SIZE 19456
TRANSACTION_PREALLOC_SIZE 20480
==+ Set values back to the default values +==
set @@range_alloc_block_size=default;
set @@query_alloc_block_size=default, @@query_prealloc_size=default;
set transaction_alloc_block_size=default, @@transaction_prealloc_size=default;
==+ Check the values now that they are reset +==
SHOW VARIABLES WHERE variable_name IN ('range_alloc_block_size',
'query_alloc_block_size', 'query_prealloc_size',
'transaction_alloc_block_size', 'transaction_prealloc_size');
Variable_name Value
query_alloc_block_size 32768
query_prealloc_size 32768
range_alloc_block_size 4096
transaction_alloc_block_size 8192
transaction_prealloc_size 4096
SELECT @@version LIKE 'non-existent';
@@version LIKE 'non-existent'
0
SELECT @@version_compile_os LIKE 'non-existent';
@@version_compile_os LIKE 'non-existent'
0
set unknown_variable=1;
ERROR HY000: Unknown system variable 'unknown_variable'
set max_join_size="hello";
ERROR 42000: Incorrect argument type to variable 'max_join_size'
set default_storage_engine=UNKNOWN_TABLE_TYPE;
ERROR 42000: Unknown storage engine 'UNKNOWN_TABLE_TYPE'
set default_storage_engine=MERGE, sql_warnings=NULL;
ERROR 42000: Variable 'sql_warnings' can't be set to the value of 'NULL'
show local variables like 'default_storage_engine';
Variable_name Value
default_storage_engine MEMORY
set character_set_client=UNKNOWN_CHARACTER_SET;
ERROR 42000: Unknown character set: 'UNKNOWN_CHARACTER_SET'
set collation_connection=UNKNOWN_COLLATION;
ERROR HY000: Unknown collation: 'UNKNOWN_COLLATION'
set character_set_client=NULL;
ERROR 42000: Variable 'character_set_client' can't be set to the value of 'NULL'
set collation_connection=NULL;
ERROR 42000: Variable 'collation_connection' can't be set to the value of 'NULL'
select @@global.timestamp;
ERROR HY000: Variable 'timestamp' is a SESSION variable
set @@version='';
ERROR HY000: Variable 'version' is a read only variable
set @@concurrent_insert=1;
ERROR HY000: Variable 'concurrent_insert' is a GLOBAL variable and should be set with SET GLOBAL
set myisam_max_sort_file_size=100;
ERROR HY000: Variable 'myisam_max_sort_file_size' is a GLOBAL variable and should be set with SET GLOBAL
set @@SQL_WARNINGS=NULL;
ERROR 42000: Variable 'sql_warnings' can't be set to the value of 'NULL'
set autocommit=1;
select @@autocommit;
@@autocommit
1
set global binlog_cache_size=100;
Warnings:
Warning 1292 Truncated incorrect binlog_cache_size value: '100'
set bulk_insert_buffer_size=100;
set character set cp1251_koi8;
set character set default;
set @@global.concurrent_insert=1;
set global connect_timeout=100;
select @@delay_key_write;
@@delay_key_write
ON
set global delay_key_write="OFF";
select @@delay_key_write;
@@delay_key_write
OFF
set global delay_key_write=ALL;
select @@delay_key_write;
@@delay_key_write
ALL
set global delay_key_write=1;
select @@delay_key_write;
@@delay_key_write
ON
set global delayed_insert_limit=100;
set global delayed_insert_timeout=100;
set global delayed_queue_size=100;
set global flush=1;
set global flush_time=100;
set insert_id=1;
set interactive_timeout=100;
set join_buffer_size=100;
Warnings:
Warning 1292 Truncated incorrect join_buffer_size value: '100'
set last_insert_id=1;
set global local_infile=1;
set long_query_time=0.000001;
select @@long_query_time;
@@long_query_time
0.000001
set long_query_time=100.000001;
select @@long_query_time;
@@long_query_time
100.000001
set low_priority_updates=1;
set global max_allowed_packet=100;
Warnings:
Warning 1292 Truncated incorrect max_allowed_packet value: '100'
Warning 1708 The value of 'max_allowed_packet' should be no less than the value of 'net_buffer_length'
set global max_binlog_cache_size=100;
Warnings:
Warning 1292 Truncated incorrect max_binlog_cache_size value: '100'
set global max_binlog_size=100;
Warnings:
Warning 1292 Truncated incorrect max_binlog_size value: '100'
set global max_connect_errors=100;
set global max_connections=100;
set global max_delayed_threads=100;
set max_heap_table_size=100;
Warnings:
Warning 1292 Truncated incorrect max_heap_table_size value: '100'
set max_join_size=100;
set max_sort_length=100;
set global max_user_connections=100;
set global max_write_lock_count=100;
set myisam_sort_buffer_size=100;
Warnings:
Warning 1292 Truncated incorrect myisam_sort_buffer_size value: '100'
set global net_buffer_length=100;
Warnings:
Warning 1292 Truncated incorrect net_buffer_length value: '100'
set net_read_timeout=100;
set net_write_timeout=100;
set read_buffer_size=100;
Warnings:
Warning 1292 Truncated incorrect read_buffer_size value: '100'
set read_rnd_buffer_size=100;
set global server_id=100;
set global slow_launch_time=100;
set sort_buffer_size=100;
Warnings:
Warning 1292 Truncated incorrect sort_buffer_size value: '100'
set @@max_sp_recursion_depth=10;
select @@max_sp_recursion_depth;
@@max_sp_recursion_depth
10
set @@max_sp_recursion_depth=0;
select @@max_sp_recursion_depth;
@@max_sp_recursion_depth
0
set sql_auto_is_null=1;
select @@sql_auto_is_null;
@@sql_auto_is_null
1
set @@sql_auto_is_null=0;
select @@sql_auto_is_null;
@@sql_auto_is_null
0
set sql_big_selects=1;
set sql_buffer_result=1;
set sql_log_bin=1;
set sql_log_off=1;
set sql_quote_show_create=1;
set sql_safe_updates=1;
set sql_select_limit=1;
set sql_select_limit=default;
set sql_warnings=1;
set @save_table_open_cache=@@table_open_cache;
set global table_open_cache=100;
set default_storage_engine=myisam;
set global thread_cache_size=100;
set timestamp=1, timestamp=default;
set tmp_table_size=16384;
set tx_isolation="READ-COMMITTED";
set wait_timeout=100;
set log_warnings=1;
set global log_warnings=1;
select @@session.insert_id;
@@session.insert_id
1
set @save_insert_id=@@session.insert_id;
set session insert_id=20;
select @@session.insert_id;
@@session.insert_id
20
set session last_insert_id=100;
select @@session.insert_id;
@@session.insert_id
20
select @@session.last_insert_id;
@@session.last_insert_id
100
select @@session.insert_id;
@@session.insert_id
20
set @@session.insert_id=@save_insert_id;
select @@session.insert_id;
@@session.insert_id
1
create table t1 (a int not null auto_increment, primary key(a));
create table t2 (a int not null auto_increment, primary key(a));
insert into t1 values(null),(null),(null);
insert into t2 values(null),(null),(null);
set global key_buffer_size=100000;
Warnings:
Warning 1292 Truncated incorrect key_buffer_size value: '100000'
select @@key_buffer_size;
@@key_buffer_size
98304
select * from t1 where a=2;
a
2
select * from t2 where a=3;
a
3
check table t1,t2;
Table Op Msg_type Msg_text
test.t1 check status OK
test.t2 check status OK
select max(a) +1, max(a) +2 into @xx,@yy from t1;
drop table t1,t2;
select @@xxxxxxxxxx;
ERROR HY000: Unknown system variable 'xxxxxxxxxx'
select 1;
1
1
select @@session.key_buffer_size;
ERROR HY000: Variable 'key_buffer_size' is a GLOBAL variable
set ft_boolean_syntax = @@init_connect;
ERROR HY000: Variable 'ft_boolean_syntax' is a GLOBAL variable and should be set with SET GLOBAL
set global ft_boolean_syntax = @@init_connect;
ERROR 42000: Variable 'ft_boolean_syntax' can't be set to the value of ''
set init_connect = NULL;
ERROR HY000: Variable 'init_connect' is a GLOBAL variable and should be set with SET GLOBAL
set global init_connect = NULL;
set ft_boolean_syntax = @@init_connect;
ERROR HY000: Variable 'ft_boolean_syntax' is a GLOBAL variable and should be set with SET GLOBAL
set global ft_boolean_syntax = @@init_connect;
ERROR 42000: Variable 'ft_boolean_syntax' can't be set to the value of ''
set global myisam_max_sort_file_size=4294967296;
show global variables like 'myisam_max_sort_file_size';
Variable_name Value
myisam_max_sort_file_size MAX_FILE_SIZE
select * from information_schema.global_variables where variable_name like 'myisam_max_sort_file_size';
VARIABLE_NAME VARIABLE_VALUE
MYISAM_MAX_SORT_FILE_SIZE MAX_FILE_SIZE
set global myisam_max_sort_file_size=default;
set @@global.max_user_connections=10, @@local.max_join_size=1000;
select @@global.max_user_connections,@@local.max_join_size;
@@global.max_user_connections @@local.max_join_size
10 1000
set @svc=@@global.max_user_connections, @svj=@@local.max_join_size;
select @@global.max_user_connections,@@local.max_join_size;
@@global.max_user_connections @@local.max_join_size
10 1000
set @@global.max_user_connections=111,@@local.max_join_size=222;
select @@global.max_user_connections,@@local.max_join_size;
@@global.max_user_connections @@local.max_join_size
111 222
set @@global.max_user_connections=@@local.max_join_size,@@local.max_join_size=@@global.max_user_connections;
select @@global.max_user_connections,@@local.max_join_size;
@@global.max_user_connections @@local.max_join_size
222 111
set @@global.max_user_connections=@svc, @@local.max_join_size=@svj;
select @@global.max_user_connections,@@local.max_join_size;
@@global.max_user_connections @@local.max_join_size
10 1000
set @a=1, @b=2;
set @a=@b, @b=@a;
select @a, @b;
@a @b
2 1
set @@global.max_user_connections=@my_max_user_connections;
set @@global.global.key_buffer_size= 1;
ERROR HY000: Unknown structured system variable or ROW routine variable 'global'
set GLOBAL global.key_buffer_size= 1;
ERROR HY000: Unknown structured system variable or ROW routine variable 'global'
SELECT @@global.global.key_buffer_size;
ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'key_buffer_size' at line 1
SELECT @@global.session.key_buffer_size;
ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'key_buffer_size' at line 1
SELECT @@global.local.key_buffer_size;
ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'key_buffer_size' at line 1
set @tstlw = @@log_warnings;
show global variables like 'log_warnings';
Variable_name Value
log_warnings 1
select * from information_schema.global_variables where variable_name like 'log_warnings';
VARIABLE_NAME VARIABLE_VALUE
LOG_WARNINGS 1
set global log_warnings = 0;
show global variables like 'log_warnings';
Variable_name Value
log_warnings 0
select * from information_schema.global_variables where variable_name like 'log_warnings';
VARIABLE_NAME VARIABLE_VALUE
LOG_WARNINGS 0
set global log_warnings = 42;
show global variables like 'log_warnings';
Variable_name Value
log_warnings 42
select * from information_schema.global_variables where variable_name like 'log_warnings';
VARIABLE_NAME VARIABLE_VALUE
LOG_WARNINGS 42
set global log_warnings = @tstlw;
show global variables like 'log_warnings';
Variable_name Value
log_warnings 1
select * from information_schema.global_variables where variable_name like 'log_warnings';
VARIABLE_NAME VARIABLE_VALUE
LOG_WARNINGS 1
create table t1 (
c1 tinyint,
c2 smallint,
c3 mediumint,
c4 int,
c5 bigint);
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`c1` tinyint(4) DEFAULT NULL,
`c2` smallint(6) DEFAULT NULL,
`c3` mediumint(9) DEFAULT NULL,
`c4` int(11) DEFAULT NULL,
`c5` bigint(20) DEFAULT NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_swedish_ci
drop table t1;
set @arg00= 8, @arg01= 8.8, @arg02= 'a string', @arg03= 0.2e0;
create table t1 as select @arg00 as c1, @arg01 as c2, @arg02 as c3, @arg03 as c4;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`c1` bigint(20) DEFAULT NULL,
`c2` decimal(65,38) DEFAULT NULL,
`c3` longtext DEFAULT NULL,
`c4` double DEFAULT NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_swedish_ci
drop table t1;
SET GLOBAL MYISAM_DATA_POINTER_SIZE= 7;
SHOW VARIABLES LIKE 'MYISAM_DATA_POINTER_SIZE';
Variable_name Value
myisam_data_pointer_size 7
SELECT * FROM INFORMATION_SCHEMA.SESSION_VARIABLES WHERE VARIABLE_NAME LIKE 'MYISAM_DATA_POINTER_SIZE';
VARIABLE_NAME VARIABLE_VALUE
MYISAM_DATA_POINTER_SIZE 7
SET GLOBAL table_open_cache=-1;
Warnings:
Warning 1292 Truncated incorrect table_open_cache value: '-1'
SHOW VARIABLES LIKE 'table_open_cache';
Variable_name Value
table_open_cache 10
SELECT * FROM INFORMATION_SCHEMA.SESSION_VARIABLES WHERE VARIABLE_NAME LIKE 'table_open_cache';
VARIABLE_NAME VARIABLE_VALUE
TABLE_OPEN_CACHE 10
SET GLOBAL table_open_cache=@save_table_open_cache;
set character_set_results=NULL;
select ifnull(@@character_set_results,"really null");
ifnull(@@character_set_results,"really null")
really null
set names latin1;
*** Various tests with LC_TIME_NAMES
*** LC_TIME_NAMES: testing case insensitivity
set @@lc_time_names='ru_ru';
select @@lc_time_names;
@@lc_time_names
ru_RU
*** LC_TIME_NAMES: testing with a user variable
set @lc='JA_JP';
set @@lc_time_names=@lc;
select @@lc_time_names;
@@lc_time_names
ja_JP
*** LC_TIME_NAMES: testing with string expressions
set lc_time_names=concat('de','_','DE');
select @@lc_time_names;
@@lc_time_names
de_DE
set lc_time_names=concat('de','+','DE');
ERROR HY000: Unknown locale: 'de+DE'
select @@lc_time_names;
@@lc_time_names
de_DE
LC_TIME_NAMES: testing with numeric expressions
set @@lc_time_names=1+2;
select @@lc_time_names;
@@lc_time_names
sv_SE
set @@lc_time_names=1/0;
ERROR 42000: Incorrect argument type to variable 'lc_time_names'
select @@lc_time_names;
@@lc_time_names
sv_SE
set lc_time_names=en_US;
LC_TIME_NAMES: testing NULL and a negative number:
set lc_time_names=NULL;
ERROR 42000: Variable 'lc_time_names' can't be set to the value of 'NULL'
set lc_time_names=-1;
ERROR HY000: Unknown locale: '-1'
select @@lc_time_names;
@@lc_time_names
en_US
LC_TIME_NAMES: testing locale with the last ID:
set lc_time_names=110;
select @@lc_time_names;
@@lc_time_names
rm_CH
LC_TIME_NAMES: testing a number beyond the valid ID range:
set lc_time_names=111;
ERROR HY000: Unknown locale: '111'
select @@lc_time_names;
@@lc_time_names
rm_CH
LC_TIME_NAMES: testing that 0 is en_US:
set lc_time_names=0;
select @@lc_time_names;
@@lc_time_names
en_US
select @@global.lc_time_names, @@lc_time_names;
@@global.lc_time_names @@lc_time_names
en_US en_US
set @@global.lc_time_names=fr_FR;
select @@global.lc_time_names, @@lc_time_names;
@@global.lc_time_names @@lc_time_names
fr_FR en_US
connect con1,localhost,root,,;
connection con1;
select @@global.lc_time_names, @@lc_time_names;
@@global.lc_time_names @@lc_time_names
fr_FR fr_FR
set @@lc_time_names=ru_RU;
select @@global.lc_time_names, @@lc_time_names;
@@global.lc_time_names @@lc_time_names
fr_FR ru_RU
disconnect con1;
connection default;
select @@global.lc_time_names, @@lc_time_names;
@@global.lc_time_names @@lc_time_names
fr_FR en_US
set lc_time_names=default;
select @@global.lc_time_names, @@lc_time_names;
@@global.lc_time_names @@lc_time_names
fr_FR fr_FR
set @@global.lc_time_names=default;
select @@global.lc_time_names, @@lc_time_names;
@@global.lc_time_names @@lc_time_names
en_US fr_FR
set @@lc_time_names=default;
select @@global.lc_time_names, @@lc_time_names;
@@global.lc_time_names @@lc_time_names
en_US en_US
set @test = @@query_prealloc_size;
set @@query_prealloc_size = @test;
select @@query_prealloc_size = @test;
@@query_prealloc_size = @test
1
set global sql_mode=repeat('a',80);
ERROR 42000: Variable 'sql_mode' can't be set to the value of 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'
End of 4.1 tests
create table t1 (a int);
select a into @x from t1;
Warnings:
Warning 1329 No data - zero rows fetched, selected, or processed
show warnings;
Level Code Message
Warning 1329 No data - zero rows fetched, selected, or processed
drop table t1;
set @@warning_count=1;
ERROR HY000: Variable 'warning_count' is a read only variable
set @@global.error_count=1;
ERROR HY000: Variable 'error_count' is a read only variable
set @@max_heap_table_size= 4294967296;
select @@max_heap_table_size > 0;
@@max_heap_table_size > 0
1
set global max_heap_table_size= 4294967296;
select @@max_heap_table_size > 0;
@@max_heap_table_size > 0
1
set @@max_heap_table_size= 4294967296;
select @@max_heap_table_size > 0;
@@max_heap_table_size > 0
1
select @@character_set_system;
@@character_set_system
utf8mb3
set global character_set_system = latin1;
ERROR HY000: Variable 'character_set_system' is a read only variable
set @@global.version_compile_os='234';
ERROR HY000: Variable 'version_compile_os' is a read only variable
set character_set_filesystem=latin1;
select @@character_set_filesystem;
@@character_set_filesystem
latin1
set @@global.character_set_filesystem=latin2;
set character_set_filesystem=latin1;
select @@character_set_filesystem;
@@character_set_filesystem
latin1
set @@global.character_set_filesystem=latin2;
set character_set_filesystem=default;
select @@character_set_filesystem;
@@character_set_filesystem
latin2
set @@global.character_set_filesystem=default;
select @@global.character_set_filesystem;
@@global.character_set_filesystem
binary
set @old_sql_big_selects = @@sql_big_selects;
set @@sql_big_selects = 1;
show variables like 'sql_big_selects';
Variable_name Value
sql_big_selects ON
select * from information_schema.session_variables where variable_name like 'sql_big_selects';
VARIABLE_NAME VARIABLE_VALUE
SQL_BIG_SELECTS ON
set @@sql_big_selects = @old_sql_big_selects;
set @@sql_notes = 0, @@sql_warnings = 0;
show variables like 'sql_notes';
Variable_name Value
sql_notes OFF
select * from information_schema.session_variables where variable_name like 'sql_notes';
VARIABLE_NAME VARIABLE_VALUE
SQL_NOTES OFF
show variables like 'sql_warnings';
Variable_name Value
sql_warnings OFF
select * from information_schema.session_variables where variable_name like 'sql_warnings';
VARIABLE_NAME VARIABLE_VALUE
SQL_WARNINGS OFF
set @@sql_notes = 1, @@sql_warnings = 1;
show variables like 'sql_notes';
Variable_name Value
sql_notes ON
select * from information_schema.session_variables where variable_name like 'sql_notes';
VARIABLE_NAME VARIABLE_VALUE
SQL_NOTES ON
show variables like 'sql_warnings';
Variable_name Value
sql_warnings ON
select * from information_schema.session_variables where variable_name like 'sql_warnings';
VARIABLE_NAME VARIABLE_VALUE
SQL_WARNINGS ON
select @@system_time_zone;
@@system_time_zone
#
select @@version, @@version_comment, @@version_compile_machine,
@@version_compile_os;
@@version @@version_comment @@version_compile_machine @@version_compile_os
# # # #
select @@basedir, @@datadir, @@tmpdir;
@@basedir @@datadir @@tmpdir
# # #
show variables like 'basedir';
Variable_name Value
basedir #
select * from information_schema.session_variables where variable_name like 'basedir';
VARIABLE_NAME VARIABLE_VALUE
BASEDIR #
show variables like 'datadir';
Variable_name Value
datadir #
select * from information_schema.session_variables where variable_name like 'datadir';
VARIABLE_NAME VARIABLE_VALUE
DATADIR #
show variables like 'tmpdir';
Variable_name Value
tmpdir #
select * from information_schema.session_variables where variable_name like 'tmpdir';
VARIABLE_NAME VARIABLE_VALUE
TMPDIR #
set sort_buffer_size=1024*8;
select @@ssl_ca, @@ssl_capath, @@ssl_cert, @@ssl_cipher, @@ssl_key;
@@ssl_ca @@ssl_capath @@ssl_cert @@ssl_cipher @@ssl_key
# # # # #
show variables like 'ssl%';
Variable_name Value
ssl_ca #
ssl_capath #
ssl_cert #
ssl_cipher #
ssl_crl #
ssl_crlpath #
ssl_key #
select * from information_schema.session_variables where variable_name like 'ssl%' order by 1;
VARIABLE_NAME VARIABLE_VALUE
SSL_CA #
SSL_CAPATH #
SSL_CERT #
SSL_CIPHER #
SSL_CRL #
SSL_CRLPATH #
SSL_KEY #
select @@log_queries_not_using_indexes;
@@log_queries_not_using_indexes
0
show variables like 'log_queries_not_using_indexes';
Variable_name Value
log_queries_not_using_indexes OFF
select * from information_schema.session_variables where variable_name like 'log_queries_not_using_indexes';
VARIABLE_NAME VARIABLE_VALUE
LOG_QUERIES_NOT_USING_INDEXES OFF
select @@"";
ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '""' at line 1
select @@&;
ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '&' at line 1
select @@@;
ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '@' at line 1
select @@hostname;
@@hostname
#
set @@hostname= "anothername";
ERROR HY000: Variable 'hostname' is a read only variable
show variables like 'hostname';
Variable_name Value
hostname #
#
# BUG#37408 - Compressed MyISAM files should not require/use mmap()
#
# Test 'myisam_mmap_size' option is not dynamic
SET @@myisam_mmap_size= 500M;
ERROR HY000: Variable 'myisam_mmap_size' is a read only variable
#
# Bug #52315: utc_date() crashes when system time > year 2037
#
SET TIMESTAMP=2*1024*1024*1024;
Warnings:
Warning 1292 Truncated incorrect timestamp value: '2147483648'
#Should not crash
SELECT UTC_DATE();
SET TIMESTAMP=DEFAULT;
End of 5.0 tests
set join_buffer_size=1;
Warnings:
Warning 1292 Truncated incorrect join_buffer_size value: '1'
set @save_join_buffer_size=@@join_buffer_size;
set join_buffer_size=@save_join_buffer_size;
set global binlog_cache_size =@my_binlog_cache_size;
set global connect_timeout =@my_connect_timeout;
set global delayed_insert_timeout =@my_delayed_insert_timeout;
set global delayed_queue_size =@my_delayed_queue_size;
set global flush =@my_flush;
set global flush_time =@my_flush_time;
set global key_buffer_size =@my_key_buffer_size;
set global max_binlog_cache_size =@my_max_binlog_cache_size;
set global max_binlog_size =@my_max_binlog_size;
set global max_connect_errors =@my_max_connect_errors;
set global max_connections =@my_max_connections;
set global max_delayed_threads =@my_max_delayed_threads;
set global max_heap_table_size =@my_max_heap_table_size;
set global max_insert_delayed_threads=@my_max_insert_delayed_threads;
set global max_join_size =@my_max_join_size;
set global max_user_connections =@my_max_user_connections;
set global max_write_lock_count =default;
set global myisam_data_pointer_size =@my_myisam_data_pointer_size;
set global myisam_max_sort_file_size =@my_myisam_max_sort_file_size;
set global net_buffer_length =@my_net_buffer_length;
Warnings:
Warning 1708 The value of 'max_allowed_packet' should be no less than the value of 'net_buffer_length'
set global net_write_timeout =@my_net_write_timeout;
set global net_read_timeout =@my_net_read_timeout;
set global server_id =@my_server_id;
set global slow_launch_time =@my_slow_launch_time;
set global default_storage_engine =@my_storage_engine;
set global thread_cache_size =@my_thread_cache_size;
set global max_allowed_packet =@my_max_allowed_packet;
set global delay_key_write =@my_delay_key_write;
set global join_buffer_size =@my_join_buffer_size;
set global log_warnings =@my_log_warnings;
set global local_infile =@my_local_infile;
show global variables where Variable_name='table_definition_cache';
Variable_name Value
table_definition_cache #
# --
# -- Bug#34820: log_output can be set to illegal value.
# --
SET GLOBAL log_output = '';
ERROR 42000: Variable 'log_output' can't be set to the value of ''
SET GLOBAL log_output = 0;
ERROR 42000: Variable 'log_output' can't be set to the value of '0'
# -- End of Bug#34820.
#
SHOW VARIABLES like 'ft_max_word_len';
Variable_name Value
ft_max_word_len 84
SELECT @@session.ft_max_word_len;
ERROR HY000: Variable 'ft_max_word_len' is a GLOBAL variable
SELECT @@global.ft_max_word_len;
@@global.ft_max_word_len
84
SET @@session.ft_max_word_len= 7;
ERROR HY000: Variable 'ft_max_word_len' is a read only variable
SET @@global.ft_max_word_len= 7;
ERROR HY000: Variable 'ft_max_word_len' is a read only variable
#
SHOW VARIABLES like 'ft_min_word_len';
Variable_name Value
ft_min_word_len 4
SELECT @@session.ft_min_word_len;
ERROR HY000: Variable 'ft_min_word_len' is a GLOBAL variable
SELECT @@global.ft_min_word_len;
@@global.ft_min_word_len
4
SET @@session.ft_min_word_len= 7;
ERROR HY000: Variable 'ft_min_word_len' is a read only variable
SET @@global.ft_min_word_len= 7;
ERROR HY000: Variable 'ft_min_word_len' is a read only variable
#
SHOW VARIABLES like 'ft_query_expansion_limit';
Variable_name Value
ft_query_expansion_limit 20
SELECT @@session.ft_query_expansion_limit;
ERROR HY000: Variable 'ft_query_expansion_limit' is a GLOBAL variable
SELECT @@global.ft_query_expansion_limit;
@@global.ft_query_expansion_limit
20
SET @@session.ft_query_expansion_limit= 7;
ERROR HY000: Variable 'ft_query_expansion_limit' is a read only variable
SET @@global.ft_query_expansion_limit= 7;
ERROR HY000: Variable 'ft_query_expansion_limit' is a read only variable
#
SHOW VARIABLES like 'ft_stopword_file';
Variable_name Value
ft_stopword_file (built-in)
SELECT @@session.ft_stopword_file;
ERROR HY000: Variable 'ft_stopword_file' is a GLOBAL variable
SELECT @@global.ft_stopword_file;
@@global.ft_stopword_file
(built-in)
SET @@session.ft_stopword_file= 'x';
ERROR HY000: Variable 'ft_stopword_file' is a read only variable
SET @@global.ft_stopword_file= 'x';
ERROR HY000: Variable 'ft_stopword_file' is a read only variable
#
SHOW VARIABLES like 'back_log';
Variable_name Value
back_log #
SELECT @@session.back_log;
ERROR HY000: Variable 'back_log' is a GLOBAL variable
SELECT @@global.back_log > 0;
@@global.back_log > 0
1
SET @@session.back_log= 7;
ERROR HY000: Variable 'back_log' is a read only variable
SET @@global.back_log= 7;
ERROR HY000: Variable 'back_log' is a read only variable
#
SHOW VARIABLES like 'large_files_support';
Variable_name Value
large_files_support #
SELECT @@session.large_files_support;
ERROR HY000: Variable 'large_files_support' is a GLOBAL variable
SELECT @@global.large_files_support;
@@global.large_files_support
#
SET @@session.large_files_support= true;
ERROR HY000: Variable 'large_files_support' is a read only variable
SET @@global.large_files_support= true;
ERROR HY000: Variable 'large_files_support' is a read only variable
#
SHOW VARIABLES like 'character_sets_dir';
Variable_name Value
character_sets_dir #
SELECT @@session.character_sets_dir;
ERROR HY000: Variable 'character_sets_dir' is a GLOBAL variable
SELECT @@global.character_sets_dir;
@@global.character_sets_dir
#
SET @@session.character_sets_dir= 'x';
ERROR HY000: Variable 'character_sets_dir' is a read only variable
SET @@global.character_sets_dir= 'x';
ERROR HY000: Variable 'character_sets_dir' is a read only variable
#
SHOW VARIABLES like 'init_file';
Variable_name Value
init_file #
SELECT @@session.init_file;
ERROR HY000: Variable 'init_file' is a GLOBAL variable
SELECT @@global.init_file;
@@global.init_file
#
SET @@session.init_file= 'x';
ERROR HY000: Variable 'init_file' is a read only variable
SET @@global.init_file= 'x';
ERROR HY000: Variable 'init_file' is a read only variable
#
SHOW VARIABLES like 'lc_messages_dir';
Variable_name Value
lc_messages_dir #
SELECT @@session.lc_messages_dir;
ERROR HY000: Variable 'lc_messages_dir' is a GLOBAL variable
SELECT @@global.lc_messages_dir;
@@global.lc_messages_dir
#
SET @@session.lc_messages_dir= 'x';
ERROR HY000: Variable 'lc_messages_dir' is a read only variable
SET @@global.lc_messages_dir= 'x';
ERROR HY000: Variable 'lc_messages_dir' is a read only variable
#
SHOW VARIABLES like 'large_page_size';
Variable_name Value
large_page_size #
SELECT @@session.large_page_size;
ERROR HY000: Variable 'large_page_size' is a GLOBAL variable
SELECT @@global.large_page_size;
@@global.large_page_size
#
SET @@session.large_page_size= 7;
ERROR HY000: Variable 'large_page_size' is a read only variable
SET @@global.large_page_size= 7;
ERROR HY000: Variable 'large_page_size' is a read only variable
#
SHOW VARIABLES like 'large_pages';
Variable_name Value
large_pages #
SELECT @@session.large_pages;
ERROR HY000: Variable 'large_pages' is a GLOBAL variable
SELECT @@global.large_pages;
@@global.large_pages
#
SET @@session.large_pages= true;
ERROR HY000: Variable 'large_pages' is a read only variable
SET @@global.large_pages= true;
ERROR HY000: Variable 'large_pages' is a read only variable
#
SHOW VARIABLES like 'log_bin';
Variable_name Value
log_bin OFF
SELECT @@session.log_bin;
ERROR HY000: Variable 'log_bin' is a GLOBAL variable
SELECT @@global.log_bin;
@@global.log_bin
0
SET @@session.log_bin= true;
ERROR HY000: Variable 'log_bin' is a read only variable
SET @@global.log_bin= true;
ERROR HY000: Variable 'log_bin' is a read only variable
#
SHOW VARIABLES like 'log_error';
Variable_name Value
log_error #
SELECT @@session.log_error;
ERROR HY000: Variable 'log_error' is a GLOBAL variable
SELECT @@global.log_error;
@@global.log_error
#
SET @@session.log_error= 'x';
ERROR HY000: Variable 'log_error' is a read only variable
SET @@global.log_error= 'x';
ERROR HY000: Variable 'log_error' is a read only variable
#
SHOW VARIABLES like 'lower_case_file_system';
Variable_name Value
lower_case_file_system #
SELECT @@session.lower_case_file_system;
ERROR HY000: Variable 'lower_case_file_system' is a GLOBAL variable
SELECT @@global.lower_case_file_system;
@@global.lower_case_file_system
#
SET @@session.lower_case_file_system= true;
ERROR HY000: Variable 'lower_case_file_system' is a read only variable
SET @@global.lower_case_file_system= true;
ERROR HY000: Variable 'lower_case_file_system' is a read only variable
#
SHOW VARIABLES like 'lower_case_table_names';
Variable_name Value
lower_case_table_names #
SELECT @@session.lower_case_table_names;
ERROR HY000: Variable 'lower_case_table_names' is a GLOBAL variable
SELECT @@global.lower_case_table_names;
@@global.lower_case_table_names
#
SET @@session.lower_case_table_names= 7;
ERROR HY000: Variable 'lower_case_table_names' is a read only variable
SET @@global.lower_case_table_names= 7;
ERROR HY000: Variable 'lower_case_table_names' is a read only variable
#
SHOW VARIABLES like 'myisam_recover_options';
Variable_name Value
myisam_recover_options BACKUP,QUICK
SELECT @@session.myisam_recover_options;
ERROR HY000: Variable 'myisam_recover_options' is a GLOBAL variable
SELECT @@global.myisam_recover_options;
@@global.myisam_recover_options
BACKUP,QUICK
SET @@session.myisam_recover_options= 'x';
ERROR HY000: Variable 'myisam_recover_options' is a read only variable
SET @@global.myisam_recover_options= 'x';
ERROR HY000: Variable 'myisam_recover_options' is a read only variable
#
SHOW VARIABLES like 'open_files_limit';
Variable_name Value
open_files_limit #
SELECT @@session.open_files_limit;
ERROR HY000: Variable 'open_files_limit' is a GLOBAL variable
SELECT @@global.open_files_limit;
@@global.open_files_limit
#
SET @@session.open_files_limit= 7;
ERROR HY000: Variable 'open_files_limit' is a read only variable
SET @@global.open_files_limit= 7;
ERROR HY000: Variable 'open_files_limit' is a read only variable
#
SHOW VARIABLES like 'pid_file';
Variable_name Value
pid_file #
SELECT @@session.pid_file;
ERROR HY000: Variable 'pid_file' is a GLOBAL variable
SELECT @@global.pid_file;
@@global.pid_file
#
SET @@session.pid_file= 'x';
ERROR HY000: Variable 'pid_file' is a read only variable
SET @@global.pid_file= 'x';
ERROR HY000: Variable 'pid_file' is a read only variable
#
SHOW VARIABLES like 'plugin_dir';
Variable_name Value
plugin_dir #
SELECT @@session.plugin_dir;
ERROR HY000: Variable 'plugin_dir' is a GLOBAL variable
SELECT @@global.plugin_dir;
@@global.plugin_dir
#
SET @@session.plugin_dir= 'x';
ERROR HY000: Variable 'plugin_dir' is a read only variable
SET @@global.plugin_dir= 'x';
ERROR HY000: Variable 'plugin_dir' is a read only variable
#
SHOW VARIABLES like 'port';
Variable_name Value
port #
SELECT @@session.port;
ERROR HY000: Variable 'port' is a GLOBAL variable
SELECT @@global.port;
@@global.port
#
SET @@session.port= 7;
ERROR HY000: Variable 'port' is a read only variable
SET @@global.port= 7;
ERROR HY000: Variable 'port' is a read only variable
#
SHOW VARIABLES like 'protocol_version';
Variable_name Value
protocol_version 10
SELECT @@session.protocol_version;
ERROR HY000: Variable 'protocol_version' is a GLOBAL variable
SELECT @@global.protocol_version;
@@global.protocol_version
10
SET @@session.protocol_version= 7;
ERROR HY000: Variable 'protocol_version' is a read only variable
SET @@global.protocol_version= 7;
ERROR HY000: Variable 'protocol_version' is a read only variable
#
SHOW VARIABLES like 'skip_external_locking';
Variable_name Value
skip_external_locking ON
SELECT @@session.skip_external_locking;
ERROR HY000: Variable 'skip_external_locking' is a GLOBAL variable
SELECT @@global.skip_external_locking;
@@global.skip_external_locking
1
SET @@session.skip_external_locking= true;
ERROR HY000: Variable 'skip_external_locking' is a read only variable
SET @@global.skip_external_locking= true;
ERROR HY000: Variable 'skip_external_locking' is a read only variable
#
SHOW VARIABLES like 'skip_networking';
Variable_name Value
skip_networking OFF
SELECT @@session.skip_networking;
ERROR HY000: Variable 'skip_networking' is a GLOBAL variable
SELECT @@global.skip_networking;
@@global.skip_networking
0
SET @@session.skip_networking= true;
ERROR HY000: Variable 'skip_networking' is a read only variable
SET @@global.skip_networking= true;
ERROR HY000: Variable 'skip_networking' is a read only variable
#
SHOW VARIABLES like 'skip_show_database';
Variable_name Value
skip_show_database OFF
SELECT @@session.skip_show_database;
ERROR HY000: Variable 'skip_show_database' is a GLOBAL variable
SELECT @@global.skip_show_database;
@@global.skip_show_database
0
SET @@session.skip_show_database= true;
ERROR HY000: Variable 'skip_show_database' is a read only variable
SET @@global.skip_show_database= true;
ERROR HY000: Variable 'skip_show_database' is a read only variable
#
SHOW VARIABLES like 'thread_stack';
Variable_name Value
thread_stack #
SELECT @@session.thread_stack;
ERROR HY000: Variable 'thread_stack' is a GLOBAL variable
SELECT @@global.thread_stack;
@@global.thread_stack
#
SET @@session.thread_stack= 7;
ERROR HY000: Variable 'thread_stack' is a read only variable
SET @@global.thread_stack= 7;
ERROR HY000: Variable 'thread_stack' is a read only variable
SELECT @@global.expire_logs_days INTO @old_eld;
SET GLOBAL expire_logs_days = -1;
Warnings:
Warning 1292 Truncated incorrect expire_logs_days value: '-1'
needs to've been adjusted (0)
SELECT @@global.expire_logs_days;
@@global.expire_logs_days
0.000000
SET GLOBAL expire_logs_days = 11;
SET @old_mode=@@sql_mode;
SET SESSION sql_mode = 'TRADITIONAL';
SET GLOBAL expire_logs_days = 100;
ERROR 42000: Variable 'expire_logs_days' can't be set to the value of '100'
needs to be unchanged (11)
SELECT @@global.expire_logs_days;
@@global.expire_logs_days
11.000000
SET SESSION sql_mode = @old_mode;
SET GLOBAL expire_logs_days = 100;
Warnings:
Warning 1292 Truncated incorrect expire_logs_days value: '100'
needs to've been adjusted (99)
SELECT @@global.expire_logs_days;
@@global.expire_logs_days
99.000000
SET GLOBAL expire_logs_days = 11;
SET GLOBAL expire_logs_days = 99;
needs to pass with no warnings (99)
SELECT @@global.expire_logs_days;
@@global.expire_logs_days
99.000000
SET GLOBAL expire_logs_days = @old_eld;
SET GLOBAL auto_increment_offset=-1;
Warnings:
Warning 1292 Truncated incorrect auto_increment_offset value: '-1'
SET GLOBAL auto_increment_offset=0;
Warnings:
Warning 1292 Truncated incorrect auto_increment_offset value: '0'
select @@default_storage_engine;
Catalog Database Table Table_alias Column Column_alias Type Length Max length Is_null Flags Decimals Charsetnr
def @@default_storage_engine 253 6 6 Y 0 39 8
@@default_storage_engine
MyISAM
SET @old_server_id = @@GLOBAL.server_id;
SET GLOBAL server_id = (1 << 32) - 1;
SELECT @@GLOBAL.server_id;
@@GLOBAL.server_id
4294967295
SET GLOBAL server_id = (1 << 32);
Warnings:
Warning 1292 Truncated incorrect server_id value: '4294967296'
SELECT @@GLOBAL.server_id;
@@GLOBAL.server_id
4294967295
SET GLOBAL server_id = (1 << 60);
Warnings:
Warning 1292 Truncated incorrect server_id value: '1152921504606846976'
SELECT @@GLOBAL.server_id;
@@GLOBAL.server_id
4294967295
SET GLOBAL server_id = 0;
Warnings:
Warning 1292 Truncated incorrect server_id value: '0'
SELECT @@GLOBAL.server_id;
@@GLOBAL.server_id
1
SET GLOBAL server_id = -1;
Warnings:
Warning 1292 Truncated incorrect server_id value: '-1'
SELECT @@GLOBAL.server_id;
@@GLOBAL.server_id
1
SET GLOBAL server_id = @old_server_id;
#
# BUG#10206 - InnoDB: Transaction requiring Max_BinLog_Cache_size > 4GB always rollsback
#
SET @old_max_binlog_cache_size = @@GLOBAL.max_binlog_cache_size;
# Set the max_binlog_cache_size to size more than 4GB.
SET GLOBAL max_binlog_cache_size = 5 * 1024 * 1024 * 1024;
SELECT @@GLOBAL.max_binlog_cache_size;
@@GLOBAL.max_binlog_cache_size
max_size
SET GLOBAL max_binlog_cache_size = @old_max_binlog_cache_size;
#
# Bug #37168 : Missing variable - skip_name_resolve
#
SELECT @@skip_name_resolve >= 0;
@@skip_name_resolve >= 0
1
SHOW VARIABLES LIKE 'skip_name_resolve';
Variable_name Value
skip_name_resolve #
#
# Bug #43233 : Some server variables are clipped during "update,"
# not "check" stage
#
SET @kbs=@@global.key_buffer_size;
SET @kcbs=@@global.key_cache_block_size;
throw errors in STRICT mode
SET SQL_MODE=STRICT_ALL_TABLES;
SET @@global.max_binlog_cache_size=-1;
ERROR 42000: Variable 'max_binlog_cache_size' can't be set to the value of '-1'
SET @@global.max_join_size=0;
ERROR 42000: Variable 'max_join_size' can't be set to the value of '0'
SET @@global.key_buffer_size=0;
ERROR HY000: Cannot drop default keycache
SET @@global.key_cache_block_size=0;
ERROR 42000: Variable 'key_cache_block_size' can't be set to the value of '0'
throw warnings in default mode
SET SQL_MODE=DEFAULT;
SET @@global.max_binlog_cache_size=-1;
Warnings:
Warning 1292 Truncated incorrect max_binlog_cache_size value: '-1'
SET @@global.max_join_size=0;
Warnings:
Warning 1292 Truncated incorrect max_join_size value: '0'
SET @@global.key_buffer_size=0;
ERROR HY000: Cannot drop default keycache
SET @@global.key_cache_block_size=0;
Warnings:
Warning 1292 Truncated incorrect key_cache_block_size value: '0'
SET @@global.max_binlog_cache_size=DEFAULT;
SET @@global.max_join_size=DEFAULT;
SET @@global.key_buffer_size=@kbs;
SET @@global.key_cache_block_size=@kcbs;
#
# Bug#11766424 59527:
# Assert in DECIMAL_BIN_SIZE:
# `SCALE >= 0 && PRECISION > 0 && SCALE <= PRE
# This test also exposed a bug with sql_buffer_result
#
CREATE TABLE t1(f1 DECIMAL(1,1) UNSIGNED);
INSERT INTO t1 VALUES (0.2),(0.1);
set @a=NULL;
set sql_buffer_result=0;
SELECT 1 as 'one' FROM t1 GROUP BY @a:= ROUND(f1);
one
1
explain SELECT 1 as 'one' FROM t1 GROUP BY @a:= (SELECT ROUND(f1) FROM t1 WHERE f1 = 0);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 2
2 SUBQUERY t1 ALL NULL NULL NULL NULL 2 Using where
SELECT 1 as 'one' FROM t1 GROUP BY @a:= (SELECT ROUND(f1) FROM t1 WHERE f1 = 0);
one
1
SELECT 1 as 'one' FROM t1 GROUP BY @a:= (SELECT ROUND(f1) FROM t1 WHERE @a=f1);
one
1
set sql_buffer_result=1;
explain SELECT 1 as 'one' FROM t1 GROUP BY @a:= (SELECT ROUND(f1) FROM t1 WHERE f1 = 0);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 2 Using temporary
2 SUBQUERY t1 ALL NULL NULL NULL NULL 2 Using where
SELECT 1 as 'one' FROM t1 GROUP BY @a:= (SELECT ROUND(f1) FROM t1 WHERE f1 = 0);
one
1
SELECT 1 as 'one' FROM t1 GROUP BY @a:= (SELECT ROUND(f1) FROM t1 WHERE @a=f1);
one
1
DROP TABLE t1;
set sql_buffer_result=0;
CREATE TABLE t1 AS SELECT @a:= CAST(1 AS UNSIGNED) AS a;
SHOW CREATE TABLE t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` int(1) unsigned NOT NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_swedish_ci
DROP TABLE t1;
End of 5.1 tests
#
# Bug#34828: OF is taken as OFF and a value of 0 is set for variable SQL_notes.
#
# Checking sql_notes...
SET @sql_notes_saved = @@sql_notes;
SET @@sql_notes = ON;
SELECT @@sql_notes;
@@sql_notes
1
SET @@sql_notes = OF;
ERROR 42000: Variable 'sql_notes' can't be set to the value of 'OF'
SELECT @@sql_notes;
@@sql_notes
1
SET @@sql_notes = OFF;
SELECT @@sql_notes;
@@sql_notes
0
SET @@sql_notes = @sql_notes_saved;
# Checking delay_key_write...
SET @delay_key_write_saved = @@delay_key_write;
SET GLOBAL delay_key_write = ON;
SELECT @@delay_key_write;
@@delay_key_write
ON
SET GLOBAL delay_key_write = OF;
ERROR 42000: Variable 'delay_key_write' can't be set to the value of 'OF'
SELECT @@delay_key_write;
@@delay_key_write
ON
SET GLOBAL delay_key_write = AL;
ERROR 42000: Variable 'delay_key_write' can't be set to the value of 'AL'
SELECT @@delay_key_write;
@@delay_key_write
ON
SET GLOBAL delay_key_write = OFF;
SELECT @@delay_key_write;
@@delay_key_write
OFF
SET GLOBAL delay_key_write = ALL;
SELECT @@delay_key_write;
@@delay_key_write
ALL
SET GLOBAL delay_key_write = @delay_key_write_saved;
# Checking sql_safe_updates...
SET @sql_safe_updates_saved = @@sql_safe_updates;
SET @@sql_safe_updates = ON;
SELECT @@sql_safe_updates;
@@sql_safe_updates
1
SET @@sql_safe_updates = OF;
ERROR 42000: Variable 'sql_safe_updates' can't be set to the value of 'OF'
SELECT @@sql_safe_updates;
@@sql_safe_updates
1
SET @@sql_safe_updates = OFF;
SELECT @@sql_safe_updates;
@@sql_safe_updates
0
SET @@sql_safe_updates = @sql_safe_updates_saved;
# Checking foreign_key_checks...
SET @foreign_key_checks_saved = @@foreign_key_checks;
SET @@foreign_key_checks = ON;
SELECT @@foreign_key_checks;
@@foreign_key_checks
1
SET @@foreign_key_checks = OF;
ERROR 42000: Variable 'foreign_key_checks' can't be set to the value of 'OF'
SELECT @@foreign_key_checks;
@@foreign_key_checks
1
SET @@foreign_key_checks = OFF;
SELECT @@foreign_key_checks;
@@foreign_key_checks
0
SET @@foreign_key_checks = @foreign_key_checks_saved;
# Checking unique_checks...
SET @unique_checks_saved = @@unique_checks;
SET @@unique_checks = ON;
SELECT @@unique_checks;
@@unique_checks
1
SET @@unique_checks = OF;
ERROR 42000: Variable 'unique_checks' can't be set to the value of 'OF'
SELECT @@unique_checks;
@@unique_checks
1
SET @@unique_checks = OFF;
SELECT @@unique_checks;
@@unique_checks
0
SET @@unique_checks = @unique_checks_saved;
# Checking sql_buffer_result...
SET @sql_buffer_result_saved = @@sql_buffer_result;
SET @@sql_buffer_result = ON;
SELECT @@sql_buffer_result;
@@sql_buffer_result
1
SET @@sql_buffer_result = OF;
ERROR 42000: Variable 'sql_buffer_result' can't be set to the value of 'OF'
SELECT @@sql_buffer_result;
@@sql_buffer_result
1
SET @@sql_buffer_result = OFF;
SELECT @@sql_buffer_result;
@@sql_buffer_result
0
SET @@sql_buffer_result = @sql_buffer_result_saved;
# Checking sql_quote_show_create...
SET @sql_quote_show_create_saved = @@sql_quote_show_create;
SET @@sql_quote_show_create = ON;
SELECT @@sql_quote_show_create;
@@sql_quote_show_create
1
SET @@sql_quote_show_create = OF;
ERROR 42000: Variable 'sql_quote_show_create' can't be set to the value of 'OF'
SELECT @@sql_quote_show_create;
@@sql_quote_show_create
1
SET @@sql_quote_show_create = OFF;
SELECT @@sql_quote_show_create;
@@sql_quote_show_create
0
SET @@sql_quote_show_create = @sql_quote_show_create_saved;
# End of Bug#34828.
# Make sure we can manipulate with autocommit in the
# along with other variables.
drop table if exists t1;
drop function if exists t1_max;
drop function if exists t1_min;
set sql_mode="";
create table t1 (a int) engine=innodb;
set sql_mode=default;
insert into t1(a) values (0), (1);
create function t1_max() returns int return (select max(a) from t1);
create function t1_min() returns int return (select min(a) from t1);
select t1_min();
t1_min()
0
select t1_max();
t1_max()
1
set @@session.autocommit=t1_min(), @@session.autocommit=t1_max(),
@@session.autocommit=t1_min(), @@session.autocommit=t1_max(),
@@session.autocommit=t1_min(), @@session.autocommit=t1_max();
# Cleanup.
drop table t1;
drop function t1_min;
drop function t1_max;
#
# Bug #59884: setting charset to 2048 crashes
#
set session character_set_results = 2048;
ERROR 42000: Unknown character set: '2048'
set session character_set_client=2048;
ERROR 42000: Unknown character set: '2048'
set session character_set_connection=2048;
ERROR 42000: Unknown character set: '2048'
set session character_set_server=2048;
ERROR 42000: Unknown character set: '2048'
set session collation_server=2048;
ERROR HY000: Unknown collation: '2048'
set session character_set_filesystem=2048;
ERROR 42000: Unknown character set: '2048'
set session character_set_database=2048;
ERROR 42000: Unknown character set: '2048'
set session collation_connection=2048;
ERROR HY000: Unknown collation: '2048'
set session collation_database=2048;
ERROR HY000: Unknown collation: '2048'
set session rand_seed1=DEFAULT;
ERROR 42000: Variable 'rand_seed1' doesn't have a default value
set autocommit = value(v);
ERROR 42S22: Unknown column 'v' in 'SET'
set session sql_mode=ansi_quotes;
select * from information_schema.session_variables where variable_name='sql_mode';
VARIABLE_NAME VARIABLE_VALUE
SQL_MODE ANSI_QUOTES
show global status like 'foobar';
Variable_name Value
select * from information_schema.session_variables where variable_name='sql_mode';
VARIABLE_NAME VARIABLE_VALUE
SQL_MODE ANSI_QUOTES
End of 5.5 tests
explain extended select @@VERsion from dual where rand() > @@verSION;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL No tables used
Warnings:
Note 1003 select @@VERsion AS "@@VERsion" from DUAL where rand() > @@version
explain extended select @@SESsion.SQL_mode from dual where rand() > @@sesSION.sql_MODE;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL No tables used
Warnings:
Note 1003 select @@SESsion.SQL_mode AS "@@SESsion.SQL_mode" from DUAL where rand() > @@sql_mode
explain extended select @@GLObal.COLLATION_connection from dual where rand() > @@gloBAL.collation_CONNECTION;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL No tables used
Warnings:
Note 1003 select @@GLObal.COLLATION_connection AS "@@GLObal.COLLATION_connection" from DUAL where rand() > @@global.collation_connection
explain extended select @@FOObar.KEY_BUFfer_size from dual where rand() > @@fooBAR.key_bufFER_SIZE;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL No tables used
Warnings:
Note 1003 select @@FOObar.KEY_BUFfer_size AS "@@FOObar.KEY_BUFfer_size" from DUAL where rand() > @@fooBAR.key_buffer_size
#
# MDEV-15316 Assertion `(thd->lex)->var_list.is_empty()' failed in MYSQLparse
#
SET GLOBAL mc.key_cache_age_threshold=100, mc.key_cache_block_size=1024;
SET GLOBAL mc.key_buffer_size= 0 /*cleanup*/;
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