当使用spfile时，不用重启就能生效的初始化参数，可以通过v$parameter.ISSYS_MODIFIABLE字段来判断。
v$parameter.ISSYS_MODIFIABLE参数
Indicates whether the parameter can be changed with ALTER SYSTEM and when the change takes effect:
IMMEDIATE - Parameter can be changed with ALTER SYSTEM regardless of the type of parameter file used to start the instance. The change takes effect immediately.
DEFERRED - Parameter can be changed with ALTER SYSTEM regardless of the type of parameter file used to start the instance. The change takes effect in subsequent sessions.
FALSE - Parameter cannot be changed with ALTER SYSTEM unless a server parameter file was used to start the instance. The change takes effect in subsequent instances.