Oracle_052_lesson_p7
Managing Database Storage Structures 管理DB存储架构you should be able to:
1、Describe the storage of table row data in blocks
2、Create and manage tablespaces
3、Obtain tablespace information
descdba_segments;
descdba_extents;
例 循环插入：
declare
begin
foriin1..100 loop
insertintohr.empselect *fromhr.employess
endloop
end
/
altersystemcheckpoint;提交内存数据写入磁盘；
创建表空间
redo ：执行的操作语句
undo ：原始数据，回滚用
connhr/hr;
select*fromsession_privs;
show parameterundo;
注：离线offlinemode有三种：normal、temporary、immediate
oracle表空间offline的三种方式区别
一 offline 表空间注意事项
1 不能离线如下表空间
system
undo tablespace
temporary tablespace
2 考虑下离线表空间对某些用户是否有影响，比如某个用户的默认表空间为你要离线的表空间。
二> normal:
A tablespace can be taken offline normally if no error conditions exist
for any of the datafiles of the tablespace. No datafile in the tablespace
can be currently offline as the result of a write error. When you specify
OFFLINE NORMAL, the database takes a checkpoint for all datafiles of the
tablespace as it takes them offline. NORMAL is the default
以上说明：
1 normal 是offline的默认方式
2 normal 对表空间的所有数据文件执行检查点操作，online表空间时不需要介质恢复。
3 normal 方式离线表空间时，不应该有写错误，表空间所有文件应该online状态。
temporary:
A tablespace can be taken offline temporarily, even if there are
error conditions for one or more files of the tablespace. When
you specify OFFLINE TEMPORARY, the database takes offline the
datafiles that are not already offline, checkpointing them as it
does so.
If no files are offline, but you use the temporary clause, media
recovery is not required to bring the tablespace back online.
However, if one or more files of the tablespace are offline
because of write errors, and you take the tablespace offline
temporarily, the tablespace requires recovery before you can
bring it back online.
以上说明：
1 offline temporary 表空间时，如果表空间中没有offline的数据文件，则online该表空间时不需要介质恢复。
2 offline temporary 表空间时，不会对已经offline的数据文件执行检查点操作，仅仅对online的数据文件执行检查点操作
3 offline temporary 表空间时，对于离线表空间之前已经offline的数据文件，则online该表空间时，offline数据文件需要介质恢复。
immediate:
A tablespace can be taken offline immediately, without the
database taking a checkpoint on any of the datafiles. When you
specify OFFLINE IMMEDIATE, media recovery for the tablespace is
required before the tablespace can be brought online. You
cannot take a tablespace offline immediately if the database is
running in NOARCHIVELOG mode.
以上说明三点：
1 offline immediate不会对表空间的任何文件执行检查点操作。
2 online 表空间时需要对所有数据文件进行 media recovery
3 offline immediate 需要数据库日志模式为归档
注意事项
如果必须离线表空间，推荐使用offline normal 方式离线该表空间，因为该表空间online时不需要执行介质恢复。
三 实验
1 测试offline temporary
查询系统当前表空间以及相应的数据文件
SQL> select a.name as tablespace,b.file#,b.status,b.name as datafile from v$tablespace a,v$datafile b where a.ts#=b.ts#;
TABLESPACE FILE# STATUSDATAFILE
SYSTEM 1 SYSTEM/oracle/CRM2/CRM/system01.dbf
SYSAUX 3 ONLINE/oracle/CRM2/CRM/sysaux01.dbf
USERS 4 ONLINE/oracle/CRM2/CRM/users01.dbf
UNDOTBS2 6 ONLINE/oracle/CRM2/CRM/undotbs2.dbf
ZX 5 ONLINE/oracle/CRM2/CRM/zx1.dbf
ZX 2 ONLINE/oracle/CRM2/CRM/zx2.dbf
SQL>>
Database> 不能用offline normal正常offline 因为表空间zx数据文件2已经offline状态
SQL>> alter tablespace zx offline
*
ERROR at line 1:
ORA-01191: file 2 is already offline - cannot do a normal offline
ORA-01110: data file 2: '/oracle/CRM2/CRM/zx2.dbf'
用offline temporary 离线
SQL>>
Tablespace>
SQL>> alter tablespace zx online
*
ERROR at line 1:
ORA-01113: file 2 needs media recovery
ORA-01110: data file 2: '/oracle/CRM2/CRM/zx2.dbf'
SQL> recover datafile 2;
Media recovery complete.
使zx表空间online
SQL>>
Tablespace> 2 测试offline immediate
查询当前表空间及其数据文件。
SQL> select a.name as tablespace,b.file#,b.status,b.name as datafile from v$tablespace a,v$datafile b where a.ts#=b.ts#;
TABLESPACE FILE# STATUSDATAFILE
SYSTEM 1 SYSTEM/oracle/CRM2/CRM/system01.dbf
SYSAUX 3 ONLINE/oracle/CRM2/CRM/sysaux01.dbf
USERS 4 ONLINE/oracle/CRM2/CRM/users01.dbf
UNDOTBS2 6 ONLINE/oracle/CRM2/CRM/undotbs2.dbf
ZX 5 ONLINE/oracle/CRM2/CRM/zx1.dbf
ZX 2 ONLINE/oracle/CRM2/CRM/zx2.dbf
SQL>>
Tablespace>
SQL>> alter tablespace zx online
*
ERROR at line 1:
ORA-01113: file 2 needs media recovery
ORA-01110: data file 2: '/oracle/CRM2/CRM/zx2.dbf'
SQL> recover datafile 2;
Media recovery complete.
SQL>> alter tablespace zx online
*
ERROR at line 1:
ORA-01113: file 5 needs media recovery
ORA-01110: data file 5: '/oracle/CRM2/CRM/zx1.dbf'
SQL> recover datafile 5;
Media recovery complete.
SQL>>
Tablespace>
例：
droptablespacetest;
createtablett1tablespacetest asselect*fromhr.regions;
删表空间： drop tablespacetest1includecontents anddatafiles;
selecttablespace_name, statusfromdba_tablespaces;
OMF->指定文件路径
SQL>selectmemberfrom v$logfile;
SQL>showparameterdb_create;
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