By Franck Pachot . Application Container brings a new way to share data among databases, and adds a new dimension to referential integrity. A foreign key in an application PDB can reference a row belonging to a root data link table. But then, should a delete on the root validate that there are no orpheans in the application PDBs? And…
By Franck Pachot . Disclaimer My goal here is only to show that the Refreshable PDB feature works by shipping and applying redo, and then can synchronize a copy of the datafiles. I do not recommend to use it for disaster recovery in any production environment yet. Even if I’m using only supported features, those features were not designed for…
By Franck Pachot . When cloning a PDB from a remote CDB you need to define a database link to be used in the CREATE PLUGGABLE DATABASE … FROM …@… command. The documentation is not completely clear about the privileges required on the source for the user defined in the database link, so here are the different possibilities. Remote clone…
By Franck Pachot . Multitenant has been introduced in 12.1.0.1 with the goal to share resources but isolate data. However, having all PDBs in the same root may be convenient to manipulate data in multiple PDBs. In the first patchset, 12.1.0.2, a way to query cross-container has been introduced for the CDB administrator to see data in other containers. In…
By Franck Pachot . If you are in multitenant, you probably already felt the desire to open the PDB$SEED in READ WRITE mode. Can you open PDB$SEED read write yourseld? Yes and No. Should you open PDB$SEED read write yourself? Yes and No. How to run upgrade scripts that need to write to PDB$SEED? catcon.pl In 12.1 you have no…
By Franck Pachot . I had a recent question about the following mention from the 12cR2 Multitenant book, about Partial PDB backups: . Here is an example in 12.2 with local undo to illustrate the answer, which may help to understand what is a partial PDB backup. Of course, since 12cR1 you can backup PDB individually, without the CDB$ROOT, in…
By Franck Pachot . Data Pump is a powerful way to save data or metadata, move it, migrate, etc. Here is an example showing few new features in 12cR1 and 12cR2. New parameters Here is the result of a diff between 12.1 and 12.2 ‘imp help=y’ But for this post, I’ll show the parameters that existed in 12.1 but have…
By Franck Pachot . Weird title, isn’t it? That was my reaction when I did my first ‘lsnrctl status’ in 12.2: weird service name… If you have installed 12.2 multitenant, then you have probably seen this strange service name registered in your listener. One per PDB. It is not a bug. It is an internal service used to connect to…
By Franck Pachot . In the Oracle Public Cloud, fast provisioning gets all its meaning when creating a RAC database service: in one hour you can get an operational highly available multitenant database. You can even create it in Data Guard for Disaster Recovery. Now, Oracle is pushing ACFS to store the datafiles rather than direct ASM. Especially in multitenant…
By Franck Pachot . When you cannot open a database, you will get some users unhappy. When you cannot open multitenant database, then the number of unhappy users is multiplied by the number of PDBs. I like to encounter problems in my lab before seeing them in production. Here is a case where I’ve lost a file. I don’t care…
By Franck Pachot . Do you like DBCA to create a database from command line, with -silent -createDatabase? On a simple command line you can provision a database, with oratab, tnsnames.ora directory creation and any setting you want. And you can even call a custom script to customize further. But if you want to put it in Data Guard, you…
By Franck Pachot . The separation of roles between system DBA and application DBA is the way to go for agile development and the PDBaaS managed service is an excellent way to play with this concept: You are PDB administrator but not the CDB administrator. Here is an example about tablespace creation/deletion, and the kind of problems that may arise…
