multitenant Archives - Page 3 of 6 - Blog dbi services
Today at UKOUG TECH16 conference I’m presenting the internals of the new multitenant architecture: 12c Multitenant: Not a Revolution, Just an Evolution. My goal is to show how it works, that metadata links and object links are not blind magic. Here are the links to the blog posts I’ve published about multitenant internals.
Easier than unplug/plug, you can move pluggable databases with remote cloning. It’s the same idea but you don’t have to manage the files yourself: the are shipped through database link. However, this uses the ‘remote file protocol’ and it fails with version mismatch: ORA-17628: Oracle error 17630 returned by remote Oracle server ORA-17630: Mismatch in the remote file protocol version client server
In the previous post I described how simple it is to unplug a PDB and plug it into a newer version CDB. One goal of dictionary separation in the multitenant architecture is to keep system objects on CDB$ROOT only. Knowing that an upgrade does not touch the application metadata and data, does this make PDB upgrade fast as a simple refresh of metadata links?
12.2 is available in the Oracle Public Cloud DBaaS. If you have a 12.1 DBaaS service, there’s no button to upgrade it. I’ll describe all the possible upgrade procedures and the first one, and the most simple, is to create a new DBaaS service in 12.2 and unplug/plug the PDBs to it.
Two years ago I filled an OTN idea to ‘Constrain PDB datafiles into specific directory’ and made it an enhancement request for 12c Release 2. When you provision a PDB, the PDB admin can create tablespaces and put datafiles anywhere in your system. Of course this is not acceptable in a cloud environment. 12.1 has a parameter for directories (PATH_PREFIX) and 12.2 brings CREATE_FILE_DEST for datafiles.
Now that 12.2 is there, in the Oracle Public Cloud Service, I can share the slides of the presentation I made for Oracle Open World: 12cR2 Single-Tenant: Multitenant Features for All Editions from Franck Pachot I’ll give the same session in French, In Geneva on November 23rd at Oracle Switzerland. Ask me if you want an invitation.
Oracle database 12.2 is there on the Database Cloud Service, in multitenant. In EE High Performance or Extreme Performance, you have the multitenant option: you can create 4096 pluggable database (instead of 252 in 12.1). If you are in lower services, you can create only one user PDB (not counting application root and proxy PDB). If you are in Standard Edition, it’s simple: it is a hard limit. If you are in simple Enterprise Edition…
Here is, in my opinion, the most beautiful feature of the multitenant architecture. You know how I love Transportable Tablespaces. But here: No need to put the source in read/only No need to export/import the metadata logically No need for any option: available even in Standard Edition