一、需求，测试12c DG 新建、删除PDB是否导致DG连通性中断
有同事之前沟通过说，搭建完成12c dg之后，由于新建、删除维护PDB，从而导致DG的中断，本篇博客对使用这种场景进行模拟测试，达到学习目的。
二、测试
2.1 主库新建一个pdb
SQL> CREATE PLUGGABLE DATABASE ypdb1 ADMIN USER ypdb1 IDENTIFIED BY oracle FILE_NAME_CONVERT =('/picclife/app/oracle/oradata/orcl/pdbseed','/picclife/app/oracle/oradata/orcl/ypdb1'); SQL> select file_name from cdb_data_files where con_id=4; FILE_NAME ---------------------------------------------------------------- /picclife/app/oracle/oradata/orcl/ypdb1/system01.dbf /picclife/app/oracle/oradata/orcl/ypdb1/sysaux01.dbf /picclife/app/oracle/oradata/orcl/ypdb1/undotbs01.dbf db_file_name_convert /picclife/app/oracle/oradata/orcl/pdbseed/, /picclife/app/oracle/oradata/orcldg/pdbseeddg/, /picclife/app/oracle/oradata/orcl/c11pdb/, /picclife/app/oracle/oradata/orcldg/c11pdbdg/, /picclife/app/oracle/oradata/orcl/, /picclife/app/oracle/oradata/orcldg/ $ pwd /picclife/app/oracle/oradata/orcldg/ypdb1 SYS@c12>select file_name from cdb_data_files where con_id=4; FILE_NAME ------------------------------------------------------------------------------------- /picclife/app/oracle/oradata/orcldg/ypdb1/system01.dbf /picclife/app/oracle/oradata/orcldg/ypdb1/sysaux01.dbf /picclife/app/oracle/oradata/orcldg/ypdb1/undotbs01.dbf
测试确认无异常，DG同步OK ！
也就是说DG 配置好完善的convert参数的情况下，会根据主库的路径自动进行转换。
例如本例中，将主库的orcl =>dg 转换为orcldg
然而PDB的名称ypdb1在搭建dg时没有，因此没有配置这个路径的转换？ 那么Oracle是如何做的，没转换就默认dg也使用这个目录！
并且新建pdb时，oracle自动在主库新建了这个文件目录，dg也同样如此！
2.2 测试pdb删除
primary drop pdb ok select con_id,pdb_name,status from cdb_pdbs; alter pluggable database YPDB1 close; drop pluggable database YPDB1 including datafiles; standby MRP0: Background Media Recovery terminated with error 65112 2021-04-20T09:24:00.069282+08:00 Errors in file /picclife/app/oracle/diag/rdbms/orcldg/c12/trace/c12_mrp0_58401.trc: ORA-65112: 未在备用数据库的所有实例上关闭可插入数据库 YPDB1 Managed Standby Recovery not using Real Time Apply Recovery interrupted! Standby recovery stopped due to failure in applying recovery marker (opcode 17.35). Datafiles are recovered to a consistent state at change 1895988 but controlfile is ahead at change 1895993. Database remains open for continuous queries. Please continue recovery. 2021-04-20T09:24:00.127559+08:00 Errors in file /picclife/app/oracle/diag/rdbms/orcldg/c12/trace/c12_mrp0_58401.trc: ORA-65112: 未在备用数据库的所有实例上关闭可插入数据库 YPDB1 2021-04-20T09:24:00.127647+08:00 MRP0: Background Media Recovery process shutdown (c12) SYS@c12> alter pluggable database YPDB1 close; SYS@c12>show pdbs CON_ID CON_NAME OPEN MODE RESTRICTED ---------- ------------------------------ ---------- ---------- 2 PDB$SEED READ ONLY NO 3 C11PDB READ ONLY NO 4 YPDB1 MOUNTED recover managed standby database using current logfile disconnect;
确认删除正常！
那么对于PDB 的12c dg convert 参数有什么需要注意的事项？
与11g一样，只要是主库与备库路径不修改，可以不配置dg convert参数；
只要涉及路径不一致的，都进行转换！
如果由于参数配置不正确，导致dg路径不一致，与11g处理类似，重新修改调整dg convert参数，完成路径转换的目的！
另外一个需要注意的是！ 主库删除pdb,DG环境 PDB可能是read only状态，MRP进程应用drop pdb 报错，MRP进程abend,造成dg同步中断！
再次重新测试一遍PDB,新建、删除，此时dg 默认新建的pdb not open,因此主库再次删除时，dg 未报错！
发现另外一个可能会遇到的问题，主库删除pdb后，再次使用相同pdb名称新建pdb, dg库可能show pdbs看不到新建的pdb,并且切换容器也看不到要重启！！！
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