SQL> create pluggable database b_pdb2
2 from MYPDB2
3 file_name_convert =
(‘E:ora12capporacleuseroradataora12cmypdb2′,’E:ora12capporacleuseroradataora12cb_pdb2’); Pluggable database created.
SQL> select dbid,name,open_mode from v$pdbs;
DBID NAME OPEN_MODE
———- —————————— ———-
4039091088 PDB$SEED READ ONLY
2213957720 B_PDB1 READ WRITE
4261134367 MYPDB2 READ ONLY
2540280635 B_PDB2 MOUNTED
SQL> alter pluggable database B_PDB2 open;
Pluggable database altered.
SQL>
常⽤检查语句：
SQL> SELECT sys_context(‘userenv’,’con_name’) MY_CONTAINER FROM dual;
MY_CONTAINER
——————–
CDB$ROOT
SQL>
SQL> SHOW con_name
CON_NAME
—
—————————
CDB$ROOT
SQL>
SQL> SELECT
2 ‘DB_NAME: ‘ ||sys_context(‘userenv’, ‘db_name’)||
3 ‘ / CDB?: ‘ ||(select cdb from v$database)||
4 ‘ / AUTH_ID: ‘ ||sys_context(‘userenv’, ‘authenticated_identity’)||
5 ‘ / USER: ‘ ||sys_context(‘userenv’, ‘current_user’)||
6 ‘ / CONTAINER: ‘||nvl(sys_Context(‘userenv’, ‘con_Name’), ‘NON-CDB’)
7 as “DB DETAILS”
8 FROM DUAL;
DB DETAILS
—————————————————————————————————-
DB_NAME: ora12c / CDB?: YES / AUTH_ID: HE-PCjijihe / USER: SYS / CONTAINER: CDB$ROOT SQL>
SQL> alter session set container=MYPDB2;
Session altered.
SQL> SELECT
2 ‘DB_NAME: ‘ ||sys_context(‘userenv’, ‘db_name’)||
3 ‘ / CDB?: ‘ ||(select cdb from v$database)||
4 ‘ / AUTH_ID: ‘ ||sys_context(‘userenv’, ‘authenticated_identity’)||
5 ‘ / USER: ‘ ||sys_context(‘userenv’, ‘current_user’)||
6 ‘ / CONTAINER: ‘||nvl(sys_Context(‘userenv’, ‘con_Name’), ‘NON-CDB’)
7 as “DB DETAILS”
8 FROM DUAL;
DB DETAILS
————————————————————————————————
DB_NAME: ora12c / CDB?: YES / AUTH_ID: HE-PCjijihe / USER: SYS / CONTAINER: MYPDB2 SQL>
SQL> select v.name, v.open_mode, stricted, ‘n/a’) “RESTRICTED”, d.status
2 from v$PDBs v inner join dba_pdbs d
3 using (GUID)
4 order ate_scn
5 /
NAME OPEN_MODE RESTRICTED STATUS
—————————— ———- ————— ————-
PDB$SEED READ ONLY NO NORMAL
MYPDB1 READ WRITE NO NORMAL
MYPDB2 READ WRITE NO NORMAL
SQL> alter pluggable database mypdb1 close;
Pluggable database altered.
SQL> select v.name, v.open_mode, stricted, ‘n/a’) “RESTRICTED”, d.status
2 from v$PDBs v inner join dba_pdbs d
3 using (GUID)
4 order ate_scn
5 /
NAME OPEN_MODE RESTRICTED STATUS
—————————— ———- ————— ————-
PDB$SEED READ ONLY NO NORMAL
MYPDB1 MOUNTED n/a NORMAL
MYPDB2 READ WRITE NO NORMAL
SQL> alter pluggable database mypdb1 open restricted;
Pluggable database altered.
SQL> select v.name, v.open_mode, stricted, ‘n/a’) “RESTRICTED”, d.status
2 from v$PDBs v inner join dba_pdbs d
3 using (GUID)
4 order ate_scn
5 /
NAME OPEN_MODE RESTRICTED STATUS
—————————— ———- ————— ————-
PDB$SEED READ ONLY NO NORMAL网络上xml是什么意思
MYPDB1 READ WRITE YES NORMAL
MYPDB2 READ WRITE NO NORMAL
SQL>
评：感觉PDB不像什么⾰命性的技术，只是将数据库⾄于mount模式后，拷贝数据⽂件，做成⼀个备份，然后将此备份plug和unplug。这样的技术，感觉跨平台的迁移不太理想。
另外，由于⼀个cdb中可以挂多个pdb，资源的分配使⽤就变得⾮常重要了，在12c中，估计原来⼏乎不常⽤的Resource Manager plan 会逐步⽤起来。
关于redo，由于redo是可以多个pdb共享，因此cdb的管理者可以通过logmnr的⽅式去挖对应pdb的⽇
志，从dump出来的redo log来看，redo log中含有container id(CON_ID，0为cdb，1为cdb$root, 2为pdb seed，3以上为pdb)，pdbid和pxid，⾄少这些信息可以⽤于区分不同pdb中的事务。
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