set @@global.tidb_max_delta_schema_count= -1;
show warnings;
Level	Code	Message
Warning	1292	Truncated incorrect tidb_max_delta_schema_count value: '-1'
select @@global.tidb_max_delta_schema_count;
@@global.tidb_max_delta_schema_count
100
set @@global.tidb_max_delta_schema_count= 9223372036854775807;
show warnings;
Level	Code	Message
Warning	1292	Truncated incorrect tidb_max_delta_schema_count value: '9223372036854775807'
select @@global.tidb_max_delta_schema_count;
@@global.tidb_max_delta_schema_count
16384
set @@global.tidb_max_delta_schema_count= invalid_val;
Error 1232 (42000): Incorrect argument type to variable 'tidb_max_delta_schema_count'
set @@global.tidb_max_delta_schema_count= 2048;
select @@global.tidb_max_delta_schema_count;
@@global.tidb_max_delta_schema_count
2048
set @@global.tidb_max_delta_schema_count= default;
SELECT @@innodb_buffer_pool_size;
@@innodb_buffer_pool_size
4294967296
SHOW VARIABLES LIKE 'innodb_buffer_pool_size';
Variable_name	Value
innodb_buffer_pool_size	4294967296
SET GLOBAL innodb_buffer_pool_size=134217728;
SELECT @@innodb_buffer_pool_size;
@@innodb_buffer_pool_size
134217728
SET GLOBAL tidb_enable_noop_variables = OFF;
SELECT @@global.tidb_enable_noop_variables;
@@global.tidb_enable_noop_variables
OFF
SELECT @@innodb_buffer_pool_size;
@@innodb_buffer_pool_size
134217728
SHOW WARNINGS;
Level	Code	Message
Warning	8145	variable innodb_buffer_pool_size has no effect in TiDB
SHOW VARIABLES LIKE 'innodb_buffer_pool_size';
Variable_name	Value
SET GLOBAL innodb_buffer_pool_size = 805306368;
SHOW WARNINGS;
Level	Code	Message
Warning	8144	setting innodb_buffer_pool_size has no effect in TiDB
SELECT @@innodb_buffer_pool_size;
@@innodb_buffer_pool_size
805306368
SET GLOBAL tidb_enable_noop_variables = 2;
Error 1231 (42000): Variable 'tidb_enable_noop_variables' can't be set to the value of '2'
SET GLOBAL tidb_enable_noop_variables = 'warn';
Error 1231 (42000): Variable 'tidb_enable_noop_variables' can't be set to the value of 'warn'
SET GLOBAL tidb_enable_noop_variables = ON;
SET GLOBAL tidb_enable_noop_variables = default;
SET GLOBAL innodb_buffer_pool_size = default;
show VARIABLES like 'character_set_%';
Variable_name	Value
character_set_client	utf8mb4
character_set_connection	utf8mb4
character_set_database	utf8mb4
character_set_filesystem	binary
character_set_results	utf8mb4
character_set_server	utf8mb4
character_set_system	utf8
character_sets_dir	/usr/local/mysql-5.6.25-osx10.8-x86_64/share/charsets/
SET NAMES latin1;
show VARIABLES like 'character_set_%';
Variable_name	Value
character_set_client	latin1
character_set_connection	latin1
character_set_database	utf8mb4
character_set_filesystem	binary
character_set_results	latin1
character_set_server	utf8mb4
character_set_system	utf8
character_sets_dir	/usr/local/mysql-5.6.25-osx10.8-x86_64/share/charsets/
SET NAMES default;
show VARIABLES like 'character_set_%';
Variable_name	Value
character_set_client	utf8mb4
character_set_connection	utf8mb4
character_set_database	utf8mb4
character_set_filesystem	binary
character_set_results	utf8mb4
character_set_server	utf8mb4
character_set_system	utf8
character_sets_dir	/usr/local/mysql-5.6.25-osx10.8-x86_64/share/charsets/
SET NAMES binary;
show VARIABLES like 'character_set_%';
Variable_name	Value
character_set_client	binary
character_set_connection	binary
character_set_database	utf8mb4
character_set_filesystem	binary
character_set_results	binary
character_set_server	utf8mb4
character_set_system	utf8
character_sets_dir	/usr/local/mysql-5.6.25-osx10.8-x86_64/share/charsets/
SET NAMES utf8;
show VARIABLES like 'character_set_%';
Variable_name	Value
character_set_client	utf8
character_set_connection	utf8
character_set_database	utf8mb4
character_set_filesystem	binary
character_set_results	utf8
character_set_server	utf8mb4
character_set_system	utf8
character_sets_dir	/usr/local/mysql-5.6.25-osx10.8-x86_64/share/charsets/
SET CHARACTER SET latin1;
show VARIABLES like 'character_set_%';
Variable_name	Value
character_set_client	latin1
character_set_connection	utf8mb4
character_set_database	utf8mb4
character_set_filesystem	binary
character_set_results	latin1
character_set_server	utf8mb4
character_set_system	utf8
character_sets_dir	/usr/local/mysql-5.6.25-osx10.8-x86_64/share/charsets/
SET CHARACTER SET default;
show VARIABLES like 'character_set_%';
Variable_name	Value
character_set_client	utf8mb4
character_set_connection	utf8mb4
character_set_database	utf8mb4
character_set_filesystem	binary
character_set_results	utf8mb4
character_set_server	utf8mb4
character_set_system	utf8
character_sets_dir	/usr/local/mysql-5.6.25-osx10.8-x86_64/share/charsets/
set names default;
select @@global.max_connections;
@@global.max_connections
0
select @@max_connections;
@@max_connections
0
set @@global.max_connections=100;
select @@global.max_connections;
@@global.max_connections
100
select @@max_connections;
@@max_connections
100
set @@global.max_connections=0;
select @@invalid;
Error 1193 (HY000): Unknown system variable 'invalid'
select @@global.invalid;
Error 1193 (HY000): Unknown system variable 'invalid'
set @@global.max_connections=default;
SELECT @@default_storage_engine;
@@default_storage_engine
InnoDB
SET GLOBAL default_storage_engine = 'somethingweird';
SET default_storage_engine = 'MyISAM';
SELECT @@default_storage_engine;
@@default_storage_engine
MyISAM
SET default_storage_engine = DEFAULT;
SELECT @@default_storage_engine;
@@default_storage_engine
somethingweird
SET @@SESSION.default_storage_engine = @@GLOBAL.default_storage_engine;
SELECT @@default_storage_engine;
@@default_storage_engine
somethingweird
SET GLOBAL default_storage_engine = 'somethingweird2';
SET default_storage_engine = @@GLOBAL.default_storage_engine;
SELECT @@default_storage_engine;
@@default_storage_engine
somethingweird2
SET default_storage_engine = DEFAULT;
SET GLOBAL default_storage_engine = DEFAULT;
SELECT @@SESSION.default_storage_engine, @@GLOBAL.default_storage_engine;
@@SESSION.default_storage_engine	@@GLOBAL.default_storage_engine
somethingweird2	InnoDB
SET GLOBAL sql_mode = 'DEFAULT';
Error 1105 (HY000): ERROR 1231 (42000): Variable 'sql_mode' can't be set to the value of 'DEFAULT'
SET GLOBAL sql_mode = DEFAULT;
set @@SESSION.default_storage_engine=default;
SET GLOBAL default_storage_engine=default;
SET GLOBAL tidb_restricted_read_only = ON;
SELECT @@GLOBAL.tidb_super_read_only;
@@GLOBAL.tidb_super_read_only
1
SET GLOBAL tidb_super_read_only = OFF;
Error 1105 (HY000): can't turn off tidb_super_read_only when tidb_restricted_read_only is on
SET GLOBAL tidb_restricted_read_only = OFF;
SELECT @@GLOBAL.tidb_restricted_read_only;
@@GLOBAL.tidb_restricted_read_only
0
SELECT @@GLOBAL.tidb_super_read_only;
@@GLOBAL.tidb_super_read_only
1
SET GLOBAL tidb_super_read_only = OFF;
SELECT @@GLOBAL.tidb_super_read_only;
@@GLOBAL.tidb_super_read_only
0
SET GLOBAL tidb_super_read_only = default;
SET GLOBAL tidb_restricted_read_only = default;
SET tidb_enable_global_temporary_table = 1;
SET tidb_slow_log_masking = 1;
SET GLOBAL tidb_enable_global_temporary_table = 1;
SET GLOBAL tidb_slow_log_masking = 1;
SELECT @@tidb_slow_log_masking;
Error 8136 (HY000): option 'tidb_slow_log_masking' is no longer supported. Reason: use tidb_redact_log instead
SELECT @@tidb_enable_global_temporary_table;
Error 8136 (HY000): option 'tidb_enable_global_temporary_table' is no longer supported. Reason: temporary table support is now always enabled
SET tidb_enable_global_temporary_table = default;
SET tidb_slow_log_masking = default;
SET GLOBAL tidb_enable_global_temporary_table = default;
SET GLOBAL tidb_slow_log_masking = default;
select @@global.tidb_session_plan_cache_size;
@@global.tidb_session_plan_cache_size
100
SET GLOBAL tidb_session_plan_cache_size = 0;
show warnings;
Level	Code	Message
Warning	1292	Truncated incorrect tidb_session_plan_cache_size value: '0'
select @@global.tidb_session_plan_cache_size;
@@global.tidb_session_plan_cache_size
1
SET GLOBAL tidb_session_plan_cache_size = 2;
select @@global.tidb_session_plan_cache_size;
@@global.tidb_session_plan_cache_size
2
select @@session.tidb_session_plan_cache_size;
@@session.tidb_session_plan_cache_size
100
SET SESSION tidb_session_plan_cache_size = 0;
show warnings;
Level	Code	Message
Warning	1292	Truncated incorrect tidb_session_plan_cache_size value: '0'
select @@session.tidb_session_plan_cache_size;
@@session.tidb_session_plan_cache_size
1
SET SESSION tidb_session_plan_cache_size = 2;
select @@session.tidb_session_plan_cache_size;
@@session.tidb_session_plan_cache_size
2
SET GLOBAL tidb_prepared_plan_cache_memory_guard_ratio = -0.1;
show warnings;
Level	Code	Message
Warning	1292	Truncated incorrect tidb_prepared_plan_cache_memory_guard_ratio value: '-0.1'
select @@global.tidb_prepared_plan_cache_memory_guard_ratio;
@@global.tidb_prepared_plan_cache_memory_guard_ratio
0
SET GLOBAL tidb_prepared_plan_cache_memory_guard_ratio = 2.2;
show warnings;
Level	Code	Message
Warning	1292	Truncated incorrect tidb_prepared_plan_cache_memory_guard_ratio value: '2.2'
select @@global.tidb_prepared_plan_cache_memory_guard_ratio;
@@global.tidb_prepared_plan_cache_memory_guard_ratio
1
SET GLOBAL tidb_prepared_plan_cache_memory_guard_ratio = 0.5;
select @@global.tidb_prepared_plan_cache_memory_guard_ratio;
@@global.tidb_prepared_plan_cache_memory_guard_ratio
0.5
SET GLOBAL tidb_enable_prepared_plan_cache = 0;
select @@global.tidb_enable_prepared_plan_cache;
@@global.tidb_enable_prepared_plan_cache
0
SET GLOBAL tidb_enable_prepared_plan_cache = 1;
select @@global.tidb_enable_prepared_plan_cache;
@@global.tidb_enable_prepared_plan_cache
1
SET GLOBAL tidb_enable_prepared_plan_cache = 0;
select @@global.tidb_enable_prepared_plan_cache;
@@global.tidb_enable_prepared_plan_cache
0
SET GLOBAL tidb_enable_prepared_plan_cache = default;
SET GLOBAL tidb_prepared_plan_cache_memory_guard_ratio = default;
SET SESSION tidb_session_plan_cache_size = default;
SET GLOBAL tidb_session_plan_cache_size = default;
set tidb_enable_legacy_instance_scope = 1;
set tidb_general_log = 1;
show warnings;
Level	Code	Message
Warning	8142	modifying tidb_general_log will require SET GLOBAL in a future version of TiDB
set tidb_enable_legacy_instance_scope = 0;
set tidb_general_log = 1;
Error 1229 (HY000): Variable 'tidb_general_log' is a GLOBAL variable and should be set with SET GLOBAL
set tidb_enable_legacy_instance_scope = default;
set tidb_general_log = default;
set global tidb_gc_max_wait_time = 1000;
set global tidb_gc_life_time = "72h";
set global tidb_gc_life_time = "24h";
set global tidb_gc_life_time = "10m";
set global tidb_gc_max_wait_time = 86400;
set global tidb_gc_life_time = "72h";
set global tidb_gc_max_wait_time = 1000;
set global tidb_gc_life_time = default;
set global tidb_gc_max_wait_time = default;
select @@tiflash_fine_grained_shuffle_stream_count;
@@tiflash_fine_grained_shuffle_stream_count
0
set @@tiflash_fine_grained_shuffle_stream_count = 0;
select @@tiflash_fine_grained_shuffle_stream_count;
@@tiflash_fine_grained_shuffle_stream_count
0
set @@tiflash_fine_grained_shuffle_stream_count = -2;
select @@tiflash_fine_grained_shuffle_stream_count;
@@tiflash_fine_grained_shuffle_stream_count
-1
set @@tiflash_fine_grained_shuffle_stream_count = 0;
select @@tiflash_fine_grained_shuffle_stream_count;
@@tiflash_fine_grained_shuffle_stream_count
0
set @@tiflash_fine_grained_shuffle_stream_count = 1024;
select @@tiflash_fine_grained_shuffle_stream_count;
@@tiflash_fine_grained_shuffle_stream_count
1024
set @@tiflash_fine_grained_shuffle_stream_count = 1025;
select @@tiflash_fine_grained_shuffle_stream_count;
@@tiflash_fine_grained_shuffle_stream_count
1024
select @@tiflash_fine_grained_shuffle_batch_size;
@@tiflash_fine_grained_shuffle_batch_size
8192
set @@tiflash_fine_grained_shuffle_batch_size = 0;
select @@tiflash_fine_grained_shuffle_batch_size;
@@tiflash_fine_grained_shuffle_batch_size
1
set @@tiflash_fine_grained_shuffle_batch_size = -1;
select @@tiflash_fine_grained_shuffle_batch_size;
@@tiflash_fine_grained_shuffle_batch_size
1
set @@tiflash_fine_grained_shuffle_batch_size = 18446744073709551615;
select @@tiflash_fine_grained_shuffle_batch_size;
@@tiflash_fine_grained_shuffle_batch_size
18446744073709551615
set global tiflash_fine_grained_shuffle_stream_count = -1;
set global tiflash_fine_grained_shuffle_batch_size = 8192;
set @@tiflash_fine_grained_shuffle_batch_size = default;
set @@tiflash_fine_grained_shuffle_stream_count = default;
set global tiflash_fine_grained_shuffle_stream_count = default;
set global tiflash_fine_grained_shuffle_batch_size = default;
drop table if exists t;
create table t(a int);
insert into t values(1);
select @@session.tiflash_fastscan;
@@session.tiflash_fastscan
0
select @@global.tiflash_fastscan;
@@global.tiflash_fastscan
0
set @@tiflash_fastscan=ON;
select @@session.tiflash_fastscan;
@@session.tiflash_fastscan
1
set global tiflash_fastscan=OFF;
select @@global.tiflash_fastscan;
@@global.tiflash_fastscan
0
set global tiflash_fastscan=default;
set @@tiflash_fastscan=default;
select @@session.tidb_enable_prepared_plan_cache_memory_monitor;
@@session.tidb_enable_prepared_plan_cache_memory_monitor
1
select @@global.tidb_enable_prepared_plan_cache_memory_monitor;
@@global.tidb_enable_prepared_plan_cache_memory_monitor
1
set @@session.tidb_enable_prepared_plan_cache_memory_monitor=OFF;
select @@session.tidb_enable_prepared_plan_cache_memory_monitor;
@@session.tidb_enable_prepared_plan_cache_memory_monitor
0
set @@session.tidb_enable_prepared_plan_cache_memory_monitor=1;
select @@session.tidb_enable_prepared_plan_cache_memory_monitor;
@@session.tidb_enable_prepared_plan_cache_memory_monitor
1
set @@global.tidb_enable_prepared_plan_cache_memory_monitor=off;
select @@global.tidb_enable_prepared_plan_cache_memory_monitor;
@@global.tidb_enable_prepared_plan_cache_memory_monitor
0
set @@session.tidb_enable_prepared_plan_cache_memory_monitor=default;
set @@global.tidb_enable_prepared_plan_cache_memory_monitor=default;
set @@tidb_enable_reuse_chunk=ON;
select @@session.tidb_enable_reuse_chunk;
@@session.tidb_enable_reuse_chunk
1
set GLOBAL tidb_enable_reuse_chunk=ON;
select @@global.tidb_enable_reuse_chunk;
@@global.tidb_enable_reuse_chunk
1
set @@tidb_enable_reuse_chunk=OFF;
select @@session.tidb_enable_reuse_chunk;
@@session.tidb_enable_reuse_chunk
0
set GLOBAL tidb_enable_reuse_chunk=OFF;
select @@global.tidb_enable_reuse_chunk;
@@global.tidb_enable_reuse_chunk
0
set @@tidb_enable_reuse_chunk=s;
Error 1231 (42000): Variable 'tidb_enable_reuse_chunk' can't be set to the value of 's'
set @@tidb_enable_reuse_chunk=default;
set GLOBAL tidb_enable_reuse_chunk=default;
select @@session.mpp_version;
@@session.mpp_version
UNSPECIFIED
SET SESSION mpp_version = -1;
select @@session.mpp_version;
@@session.mpp_version
-1
SET SESSION mpp_version = 0;
select @@session.mpp_version;
@@session.mpp_version
0
SET SESSION mpp_version = 1;
select @@session.mpp_version;
@@session.mpp_version
1
SET SESSION mpp_version = 2;
select @@session.mpp_version;
@@session.mpp_version
2
SET SESSION mpp_version = unspecified;
select @@session.mpp_version;
@@session.mpp_version
unspecified
SET SESSION mpp_version = 4;
Error 1105 (HY000): incorrect value: 4. mpp_version options: -1 (unspecified), 0, 1, 2, 3
SET GLOBAL mpp_version = 1;
select @@global.mpp_version;
@@global.mpp_version
1
SET GLOBAL mpp_version = -1;
select @@global.mpp_version;
@@global.mpp_version
-1
SET SESSION mpp_version = default;
set global mpp_version = default;
SET SESSION mpp_exchange_compression_mode = 123;
Error 1105 (HY000): incorrect value: `123`. mpp_exchange_compression_mode options: NONE, FAST, HIGH_COMPRESSION, UNSPECIFIED
select @@session.mpp_exchange_compression_mode;
@@session.mpp_exchange_compression_mode
UNSPECIFIED
SET SESSION mpp_exchange_compression_mode = none;
select @@session.mpp_exchange_compression_mode;
@@session.mpp_exchange_compression_mode
none
SET SESSION mpp_exchange_compression_mode = fast;
select @@session.mpp_exchange_compression_mode;
@@session.mpp_exchange_compression_mode
fast
SET SESSION mpp_exchange_compression_mode = HIGH_COMPRESSION;
select @@session.mpp_exchange_compression_mode;
@@session.mpp_exchange_compression_mode
HIGH_COMPRESSION
SET GLOBAL mpp_exchange_compression_mode = none;
select @@global.mpp_exchange_compression_mode;
@@global.mpp_exchange_compression_mode
none
SET mpp_version = 0;
SET mpp_exchange_compression_mode = unspecified;
SET mpp_version = 0;
SET mpp_exchange_compression_mode = HIGH_COMPRESSION;
SET mpp_version = default;
SET mpp_exchange_compression_mode = default;
set @@global.mpp_exchange_compression_mode = default;
set @@global.tidb_enable_tiflash_pipeline_model = 1;
show warnings;
Level	Code	Message
Warning	1681	tidb_enable_tiflash_pipeline_model is deprecated and will be removed in a future release.
set @@global.tidb_enable_tiflash_pipeline_model = default;