By Franck Pachot . Can we shutdown abort a PDB? Let’s try: SQL> show con_id CON_ID —————————— 3SQL> shutdown abort; Pluggable Database closed. But is it really a shutdown abort? The shutdown abort we know in non-CDB – or in a CDB from CDB$ROOT – is used when the instance cannot checkpoint before closing the file. It leaves the files…
By Franck Pachot . There has been the announce that non-CDB is deprecated, and the reaction that CDB is not yet stable. Well. Let’s talk about the major issue I’ve encountered. Multitenant is there for consolidation. What is the major requirement of consolidation? It’s availability. If you put all your databases into one server and managed by one instance, then…
By Franck Pachot . I’ve not finished with my investigation on 12c multitenant dictionary. Here, I’m checking how metadata links are managed by the dictionary cache (aka rowcache). As I did previously, I’ll create a metadata link function in my lab environment (this is not for production. For the moment metadata/object links are supported only for oracle objects). SQL> connect…
By Franck Pachot . This is a question that starts to be raised quite frequently. Oracle released the multitenant architecture 1.5 year ago. And now says that the previous architecture – known as non-CDB – is deprecated. What does it mean? Do we have to go to the CDB architecture even if we don’t want to use/pay multi-tenant? It started…
By Franck Pachot . This is a second part of the previous post about metadata link. I’ve shown how a sharing=metadata function becomes a sharing=none function when it is changed in the pdb – i.e when not having the same DDL, not having a different signature. Here is another experimentation doing the opposite: change the function in root and see…
By Franck Pachot . As in previous posts (1 and 2) I’m still playing with multitenant dictionary. You may wonder why I’m spending time to do unsupported things that we will never be able to use in real life. Of course, playing with internals is fun 😉 But it’s not only that. We will implement CDB databases (multi-tenant, and single-tenant…
By Franck Pachot . I’ve described Oracle 12c metadata and object links internals in a previous post. But before that, the first time I investigated on it, I made a wrong assumption because I was looking at AUDIT_ACTIONS which is not correctly implemented. That investigation came from a question on dba-village. And recently Ivica Arsov (@IvicaArsov) has made an interesting…
By Franck Pachot . How to migrate from non-CDB to CDB? Of course all known migration methods works. But there is also another solution: upgrade to 12c if necessary and then convert the non-CDB to a PDB. This is done with the noncdb_to_pdb.sql which converts a non-CDB dictionary to a PDB one, with metadata and object links. But do you…
By Franck Pachot . I’ve blogged about multitenant internals at the time when 12.1.0.1 was just released. Something has changed in 12.1.0.2 and blogging about it was in my todo list for a long time. Now the occasion to do it has been triggered by a question on Oracle Forums about CDB_DATA_FILES not showing PDB$SEED datafiles because there is an…
By Franck Pachot . Do you know why Oracle Database is a leader in the database market since 30 years? Do you know any other software that is still the leading solution after decades? I think that it is because Oracle has been a good software from the get-go. Many early decisions in the software architecture have revealed themselves later…
By Franck Pachot . Your datafiles have grown in the past but now you want to reclaim as much space as possible, because you are short on filesystem space, or you want to move some files without moving empty blocks, or your backup size is too large. ALTER DATABASE DATAFILE … RESIZE can reclaim the space at the end of…
By Franck Pachot . Do you remember last year, when 12c arrived with multitenant, David Hueber warned us about the fact that a single PDB can, under certain conditions, generate a complete system downtime? We are beta testers and opened a SR for that. Now one year later the first patchset is out and obviously I checked if the issue…
