dbca 小插曲

dbca 功能越来越强大，19c中可以利用它克隆pdb、relocate pdb、创建standby，测试环境上创建数据库比较方便，但有个注意的事项：创建过程中，最好不要另开窗口对数据库操作而不关闭。

一次创建测试库时发现很慢，看告警日志发现在扩展3、4号数据文件，这是因为General_Purpose.dbc中定义的文件初始值大小只有几百兆，于是想另开一个窗口，直接将这两个文件大小设置为1G，岂不高效？alter database datafile 3,4 resize 1g; 执行完后没有退出sqlplus，这就带来问题了，dbca创建过程中会多次启动实例，但是如果有活动会话他就会报错，导致一些不可预知的问题，例如字符集没有设置正确...

基本过程如下：

创建测试库
$dbca -silent -createDatabase -templateName General_Purpose.dbc -gdbname orcl -sid orcl -characterSet ZHS16GBK -sysPassword oracle -systemPassword oracle -totalMemory 1048 -redoLogFileSize 200 -datafileDestination /u01/app/oracle/oradata
[WARNING] [DBT-06208] The 'SYS' password entered does not conform to the Oracle recommended standards.
   CAUSE:
a. Oracle recommends that the password entered should be at least 8 characters in length, contain at least 1 uppercase character, 1 lower case character and 1 digit [0-9].
b.The password entered is a keyword that Oracle does not recommend to be used as password
   ACTION: Specify a strong password. If required refer Oracle documentation for guidelines.
[WARNING] [DBT-06208] The 'SYSTEM' password entered does not conform to the Oracle recommended standards.
   CAUSE:
a. Oracle recommends that the password entered should be at least 8 characters in length, contain at least 1 uppercase character, 1 lower case character and 1 digit [0-9].
b.The password entered is a keyword that Oracle does not recommend to be used as password
   ACTION: Specify a strong password. If required refer Oracle documentation for guidelines.
上面提示sys、system密码太简单，建议设置为复杂的密码
Prepare for db operation
10% complete
Copying database files
40% complete
Creating and starting Oracle instance
42% complete
46% complete  这里速度很慢（超过3分钟），于是开了另一个sqlplus窗口，修改文件大小，但是没退出sqlplus
[WARNING] ORA-12721: operation cannot execute when other sessions are active
这里出现警告，可能出现不可预知的问题
50% complete
54% complete
60% complete
Completing Database Creation
66% complete
69% complete
70% complete
Executing Post Configuration Actions
100% complete
Database creation complete. For details check the logfiles at:
 /u01/app/oracle/cfgtoollogs/dbca/orcl.
Database Information:
Global Database Name:orcl
System Identifier(SID):orcl
Look at the log file "/u01/app/oracle/cfgtoollogs/dbca/orcl/orcl.log" for further details.日志里没啥，可以参考一下告警日志内容，不放心还是删除重建吧
[oracle@apex ~]$ dbca -silent -deletedatabase -sourcedb orcl
Enter SYS user password:

[WARNING] [DBT-19202] The Database Configuration Assistant will delete the Oracle instances and datafiles for your database. All information in the database will be destroyed.
Prepare for db operation
32% complete
Connecting to database
35% complete
39% complete
42% complete
45% complete
48% complete
52% complete
65% complete
Updating network configuration files
68% complete
Deleting instance and datafiles
84% complete
100% complete
Database deletion completed.
Look at the log file "/u01/app/oracle/cfgtoollogs/dbca/orcl/orcl0.log" for further details.

解决办法是：
1、扩容后立即退出sqlplus
或者
2、创建db前先修改General_Purpose.dbc中内容
 

vi $ORACLE_HOME/assistants/dbca/templates/General_Purpose.dbc

对于创建数据库的速度会有一点点提升。
方法2 经验证无效唉 :(