1.离线模式

不提供服务，不能执行任何操作。
相关报错或提示如下。
执行数据库管理员命令时：

shared memory not initialized for GBASEDBTSERVER ‘gbaseserver’

执行数据库SQL操作时：

908: Attempt to connect to database server (gbaseserver) failed.

执行dbaccess时，可以出现菜单，选择数据库出现RUNNING后，一段时间报错。
切换到离线模式时，所有进程都会被杀死。

2.在线模式

可以执行各种操作。

3.单用户模式

也称为管理员模式。
可以执行SQL操作和命令行维护操作。只能管理员（GBASEDBT / DBSA）连接，其它普通用户不能连接。
相关报错或提示如下：

27010: Only an administrative user can connect in administrative user mode.

切换成单用户模式时，所有不是超级管理员的连接将被杀死。

4.静态模式

只能执行命令行维护操作（如备份数据库）。
不能执行SQL命令。
相关报错或提示如下：

27002: No connections are allowed in quiescent mode.

GBase 8s的三种过渡状态

• 初始化（Initialization）
  当数据库从离线状态过渡到其他状态时，会经历初始化过程，将磁盘数据加载到共享内存，以及其他初始化操作。
• 快速恢复（Fast Recovery）
  当数据库因为意外原因重启，这时候需要处理事务从而恢复到一致性状态。
• 关闭（Shutting Down）
  不允许新的连接连接到数据库。

GBase 8s的模式转换状态图

GBase 8s的模式切换演示

离线转单用户

[gbasedbt@devsvr ~]$ onstat -
Your evaluation license will expire on 2022-06-18 00:00:00
shared memory not initialized for GBASEDBTSERVER 'gbaseserver'

[gbasedbt@devsvr ~]$ oninit -j
Your evaluation license will expire on 2022-06-18 00:00:00

[gbasedbt@devsvr ~]$ onstat -
Your evaluation license will expire on 2022-06-18 00:00:00
Single-User -- Up 00:00:14 -- 597864 Kbytes

单用户转在线

[gbasedbt@devsvr ~]$ onstat -
Your evaluation license will expire on 2022-06-18 00:00:00
Single-User -- Up 00:04:33 -- 597864 Kbytes

[gbasedbt@devsvr ~]$ onmode -m
Your evaluation license will expire on 2022-06-18 00:00:00

[gbasedbt@devsvr ~]$ onstat -
Your evaluation license will expire on 2022-06-18 00:00:00
On-Line -- Up 00:04:53 -- 597864 Kbytes

离线转在线

[gbasedbt@devsvr ~]$ onstat -
Your evaluation license will expire on 2022-06-18 00:00:00
shared memory not initialized for GBASEDBTSERVER 'gbaseserver'

[gbasedbt@devsvr ~]$ oninit
Your evaluation license will expire on 2022-06-18 00:00:00

[gbasedbt@devsvr ~]$ onstat -
Your evaluation license will expire on 2022-06-18 00:00:00
On-Line -- Up 00:00:14 -- 597864 Kbytes

离线转静态

[gbasedbt@devsvr ~]$ onstat -
Your evaluation license will expire on 2022-06-18 00:00:00
shared memory not initialized for GBASEDBTSERVER 'gbaseserver'

[gbasedbt@devsvr ~]$ oninit -s
Your evaluation license will expire on 2022-06-18 00:00:00

[gbasedbt@devsvr ~]$ onstat -
Your evaluation license will expire on 2022-06-18 00:00:00
Quiescent -- Up 00:00:15 -- 597864 Kbytes

静态转在线

[gbasedbt@devsvr ~]$ onstat -
Your evaluation license will expire on 2022-06-18 00:00:00
Quiescent -- Up 00:00:15 -- 597864 Kbytes

[gbasedbt@devsvr ~]$ onmode -m
Your evaluation license will expire on 2022-06-18 00:00:00

[gbasedbt@devsvr ~]$ onstat -
Your evaluation license will expire on 2022-06-18 00:00:00
On-Line -- Up 00:00:49 -- 597864 Kbytes

在线转单用户

[gbasedbt@devsvr ~]$ onstat -
Your evaluation license will expire on 2022-06-18 00:00:00
On-Line -- Up 00:00:56 -- 597864 Kbytes

[gbasedbt@devsvr ~]$ onmode -j
Your evaluation license will expire on 2022-06-18 00:00:00
This will change mode to single user. Only DBSA/gbasedbt can connect 
in this mode.
Do you wish to continue (y/n)? y

All threads which are not owned by DBSA/gbasedbt will be killed.
Do you wish to continue (y/n)? y

[gbasedbt@devsvr ~]$ onstat -
Your evaluation license will expire on 2022-06-18 00:00:00
Single-User -- Up 00:01:25 -- 597864 Kbytes

单用户转离线

[gbasedbt@devsvr ~]$ onstat -
Your evaluation license will expire on 2022-06-18 00:00:00
Single-User -- Up 00:00:14 -- 597864 Kbytes

[gbasedbt@devsvr ~]$ onmode -k
Your evaluation license will expire on 2022-06-18 00:00:00

This will take GBase Database Server OFF-LINE -
Do you wish to continue (y/n)? y

There are 0 user threads that will be killed.
Do you wish to continue (y/n)? y

[gbasedbt@devsvr ~]$ onstat -
Your evaluation license will expire on 2022-06-18 00:00:00
shared memory not initialized for GBASEDBTSERVER 'gbaseserver'

在线转离线

[gbasedbt@devsvr ~]$ onstat -
Your evaluation license will expire on 2022-06-18 00:00:00
On-Line -- Up 00:04:53 -- 597864 Kbytes

[gbasedbt@devsvr ~]$ onmode -k
Your evaluation license will expire on 2022-06-18 00:00:00

This will take GBase Database Server OFF-LINE -
Do you wish to continue (y/n)? y

There are 0 user threads that will be killed.
Do you wish to continue (y/n)? y

[gbasedbt@devsvr ~]$ onstat -
Your evaluation license will expire on 2022-06-18 00:00:00
shared memory not initialized for GBASEDBTSERVER 'gbaseserver'

在线转静态有两种方式：
等用户执行完毕再切换

[gbasedbt@devsvr ~]$ onstat -
Your evaluation license will expire on 2022-06-18 00:00:00
On-Line -- Up 00:00:14 -- 597864 Kbytes

[gbasedbt@devsvr ~]$ onmode -s
Your evaluation license will expire on 2022-06-18 00:00:00

This will perform a GRACEFUL SHUTDOWN -
Do you wish to continue (y/n)? y

[gbasedbt@devsvr ~]$ onstat -
Your evaluation license will expire on 2022-06-18 00:00:00
Quiescent -- Up 00:00:45 -- 597864 Kbytes

或立即切换

[gbasedbt@devsvr ~]$ onstat -
Your evaluation license will expire on 2022-06-18 00:00:00
On-Line -- Up 00:00:38 -- 597864 Kbytes

[gbasedbt@devsvr ~]$ onmode -u
Your evaluation license will expire on 2022-06-18 00:00:00

This will perform an IMMEDIATE SHUTDOWN -
Do you wish to continue (y/n)? y

There are 0 user threads that will be killed.
Do you wish to continue (y/n)? y

[gbasedbt@devsvr ~]$ onstat -
Your evaluation license will expire on 2022-06-18 00:00:00
Quiescent -- Up 00:00:53 -- 597864 Kbytes

静态转离线

[gbasedbt@devsvr ~]$ onstat -
Your evaluation license will expire on 2022-06-18 00:00:00
Quiescent -- Up 00:00:45 -- 597864 Kbytes

[gbasedbt@devsvr ~]$ onmode -k
Your evaluation license will expire on 2022-06-18 00:00:00

This will take GBase Database Server OFF-LINE -
Do you wish to continue (y/n)? y

There are 0 user threads that will be killed.
Do you wish to continue (y/n)? y

[gbasedbt@devsvr ~]$ onstat -
Your evaluation license will expire on 2022-06-18 00:00:00
shared memory not initialized for GBASEDBTSERVER 'gbaseserver'

附：GBase 8s的模式与转换状态表

	离线	在线	单用户	静态
离线		oninit	oninit -j	oninit -s
在线	onmode -ky		onmode -j	onmode -s 或 onmode -u
单用户	onmode -ky	onmode -m		onmode -s 或 onmode -u
静态	onmode -ky	onmode -m	onmode -j

关闭数据库

onmode -k会导致数据库关闭后处于不一致状态，再启动时会恢复。

建议是先切换成静态模式onmode -s等待事务提交，再关闭。

如果窗口期不够，则onmode -u将事务回滚，再关闭。