SET @start_global_value = @@global.rowid_merge_buff_size;
select @@global.rowid_merge_buff_size;
@@global.rowid_merge_buff_size
8388608
select @@session.rowid_merge_buff_size;
@@session.rowid_merge_buff_size
8388608
show global variables like 'rowid_merge_buff_size';
Variable_name	Value
rowid_merge_buff_size	8388608
show session variables like 'rowid_merge_buff_size';
Variable_name	Value
rowid_merge_buff_size	8388608
select * from information_schema.global_variables where variable_name='rowid_merge_buff_size';
VARIABLE_NAME	VARIABLE_VALUE
ROWID_MERGE_BUFF_SIZE	8388608
select * from information_schema.session_variables where variable_name='rowid_merge_buff_size';
VARIABLE_NAME	VARIABLE_VALUE
ROWID_MERGE_BUFF_SIZE	8388608
set global rowid_merge_buff_size=10;
select @@global.rowid_merge_buff_size;
@@global.rowid_merge_buff_size
10
set session rowid_merge_buff_size=10;
select @@session.rowid_merge_buff_size;
@@session.rowid_merge_buff_size
10
set global rowid_merge_buff_size=1.1;
ERROR 42000: Incorrect argument type to variable 'rowid_merge_buff_size'
set session rowid_merge_buff_size=1e1;
ERROR 42000: Incorrect argument type to variable 'rowid_merge_buff_size'
set global rowid_merge_buff_size="foo";
ERROR 42000: Incorrect argument type to variable 'rowid_merge_buff_size'
set global rowid_merge_buff_size=0;
select @@global.rowid_merge_buff_size;
@@global.rowid_merge_buff_size
0
set session rowid_merge_buff_size=cast(-1 as unsigned int);
Warnings:
Note	1105	Cast to unsigned converted negative integer to it's positive complement
Warning	1292	Truncated incorrect rowid_merge_buff_size value: '18446744073709551615'
select @@session.rowid_merge_buff_size;
@@session.rowid_merge_buff_size
9223372036854775807
SET @@global.rowid_merge_buff_size = @start_global_value;
