DB2如何停库/如何使数据库处于offline状态

问题：

DB2中有些操作要求数据库处于非激活，或者说离线(offline)状态，这时候需要停库操作，比如db2dart要求数据库是offline的，那什么样的数据库才是离线状态的？如何停库？

答：

首先需要确认一点，停库和停实例是两个概念。停库是指是使database处于非激活状态，而停实例使用的命令是db2stop

1.激活数据库的2种方法

有两种办法可以激活数据库，第一种是显式地激活，即使用db2 activate database <dbname>。第二种是隐式地激活，当有首个连接到数据库时，数据库会被隐式激活，即db2 connect to <dbname>

2.查看数据库是否处于活动状态

使用db2 list active databases，如下例，数据库SAMPLE处于活动状态

C:\windows\system32> db2 "list active databases"

                           Active Databases

Database name                              = SAMPLE

Applications connected currently           = 0

Database path                              = C:\DB2INST1\NODE0000\SQL00005\MEMBER0000\

3.停库的办法

这个要根据数据库是显式地激活，还是隐式地激活的。如果是显式地激活的，必须使用db2 deactivate db <dbname>，如果是隐式地激活，最后一个连接断开时，库自然停掉。

测试1. 显示地激活数据库，使用list applications查看，虽然没有连接，但数据库是活动状态。

C:\windows\system32>db2 "activate db sample"
DB20000I  The ACTIVATE DATABASE command completed successfully.

C:\windows\system32>db2 "list active databases"

Active Databases

Database name                              = SAMPLE
Applications connected currently           = 0
Database path                              = C:\DB2INST1\NODE0000\SQL00005\MEMBER0000\

C:\windows\system32>db2 "list applications"
SQL1611W  No data was returned by Database System Monitor.

C:\windows\system32>db2 "deactivate db sample"
DB20000I  The DEACTIVATE DATABASE command completed successfully.

C:\windows\system32>db2 "list active databases"
SQL1611W  No data was returned by Database System Monitor.

测试2. 隐式地激活数据库，使用list applications查看，有连接，并且数据库是活动状态

C:\windows\system32>db2 "connect to sample"

Database Connection Information

Database server        = DB2/NT64 10.5.6
SQL authorization ID   = MIAOQING...
Local database alias   = SAMPLE

C:\windows\system32>db2 "list applications"

Auth Id  Application    Appl.      Application Id                                                 DB       # of
Name           Handle                                                                    Name    Agents
-------- -------------- ---------- -------------------------------------------------------------- -------- -----
MIAOQIN> db2bp.exe      130        *LOCAL.DB2INST1.160923021540                                   SAMPLE   1

C:\windows\system32>db2 "list active databases"

Active Databases

Database name                              = SAMPLE
Applications connected currently           = 1
Database path                              = C:\DB2INST1\NODE0000\SQL00005\MEMBER0000\

C:\windows\system32>db2 "terminate"
DB20000I  The TERMINATE command completed successfully.

C:\windows\system32>db2 "list applications"
SQL1611W  No data was returned by Database System Monitor.

C:\windows\system32>db2 "list active databases"
SQL1611W  No data was returned by Database System Monitor.

补充说明：一个实例下可能有多个库，而db2 force applications all会断掉整个实例下所有库的连接，并且，如果数据是被显式激活的，即使所有应用都被force掉了，数据库也是活动状态的。