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Franck Pachot

Oracle disables your multitenant option when you run on EC2

By | Cloud, Oracle | 6 Comments

I have installed Oracle 19.6 on an EC2 for our Multitenant Workshop training. And of course, during the workshop we create a lot of PDBs. If you don’t have paid for the Enterprise Edition plus the Multitenant Option you can create at most 3 pluggable database. But with this option you can create up to 252 pluggable databases. Does it worth the price, which according to the public price list is USD 47,500 + 17,500…

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Franck Pachot

Multitenant, PDB, ‘save state’, services and standby databases

By | Oracle | 2 Comments

By Franck Pachot . Creating – and using – your own services has always been the recommendation. You can connect to a database without a service name, though the instance SID, but this is not what you should do. Each database registers its db_unique_name as a service, and you can use it to connect, but it is always better to create your own application service(s). In multitenant, each PDB registers its name as a service,…

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Franck Pachot

12c Multitenant internals: PDB replay DDL for common users

By | Oracle | No Comments

By Franck Pachot . In multitenant, you can create common Users, Roles, and Profiles. You create them in CDB$ROOT, with the CONTAINER=ALL clause (which is optional because it is the only possible value when connected to CDB$ROOT) but they are visible to all containers. As the goal of multitenant is to avoid to duplicate common metadata to all containers, You may think that they are visible through those magic metadata links. But that’s actually wrong:…

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Franck Pachot

12c Multitenant Internals: compiling system package from PDB

By | Oracle | No Comments

By Franck Pachot . When I explain the multitenant internals, I show that all metadata about system procedures and packages are stored only in CDB$ROOT and are accessed from the PDBs through metadata links. I take an example with DBMS_SYSTEM that has nothing in SOURCE$ of the PDB. But I show that we can compile it from the PDB. This is my way to prove that the session can access the system objects, internally switching…

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Franck Pachot

Multitenant internals: INT$ and INT$INT$ views

By | Oracle | No Comments

By Franck Pachot . This month, I’ll talk – with lot of demos – about multitenant internals at DOAG conference. The multitenant dictionary architecture starts with a simple idea: system metadata and data are in CDB$ROOT and user metadata and data are in PDB. And it could have been that simple. When a session connected to a PDB needs to read some system information, the session context is switched to the CDB$ROOT container and reads…

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Franck Pachot

Wrong result with multitenant, dba_contraints and current_schema

By | Oracle | No Comments

By Franck Pachot . Multitenant architecture is not such a big change and this is why I recommend it when you start a project in 12c or if you upgrade to 12.2 – of course after thoroughly testing your application. However, there is a point where you may encounter problems on dictionary queries, because it is really a big change internally. The dictionary separation has several side effects. You should test carefully the queries you…

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Franck Pachot

Active Data Guard services in Multitenant

By | Oracle | No Comments

By Franck Pachot . A database (or the CDB in multitenant) registers its name as the default service. When a standby database is on the same server, or same cluster, you have no problem because this database name is the db_unique_name which is different between the primary and the standby(s). In multitenant, in addition to that, each PDB registers its name as a service. But the PDB name is the same in the primary and…

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