MySQL Variables rand_seed1 数据库 参数变量解释及正确配置使用
本站中文解释
和rand_seed2
rand_seed1和rand_seed2是MySQL随机数生成器相关参数,用于生成伪随机数。MySQL随机数生成器使用一个48位状态来存储当前的状态,其中包含24位rand_seed1和24位rand_seed2。通常情况下,如果不设定这两个参数,MySQL会根据系统时间自动生成这两个值,并保存到数据目录中的my.cnf文件或者my-new.cnf文件中。
要设置这两个参数,可以在系统的my.cnf或者my-new.cnf文件中添加这些参数:
[mysqld]
rand_seed1=500000 # 随机数种子1
rand_seed2=70000 # 随机数种子2
要生效,可以重启数据库,或者运行命令:
mysqladmin flush-privileges –p
重点:MySQL随机数生成器参数rand_seed1和rand_seed2是用于生成伪随机数,通过在my.cnf或者my-new.cnf文件中设置这两个参数来调整伪随机数的输出,即可使设置生效。
官方英文解释
rand_seed1
System Variable | rand_seed1 |
---|---|
Scope | Session |
Dynamic | Yes |
Type | Integer |
Default Value | N/A |
Minimum Value | 0 |
Maximum Value | 4294967295 |
The rand_seed1
and
rand_seed2
variables exist as
session variables only, and can be set but not read. The
variables—but not their values—are shown in the
output of SHOW VARIABLES
.
The purpose of these variables is to support replication of
the RAND()
function. For
statements that invoke RAND()
,
the source passes two values to the replica, where they are
used to seed the random number generator. The replica uses
these values to set the session variables
rand_seed1
and
rand_seed2
so that
RAND()
on the replica generates
the same value as on the source.