Friday, April 25, 2014

Creating Controlfile From Scratch when No Backup is Available

You have lost the controlfile, the catalog and the backup to the controlfile too; so restoring the controlfile from a previous backup is not an option. How can you recover the database? By creating the controlfile from scratch. Interested in learning how? Read on.

Thursday, April 24, 2014

How to Get the DBID when Instance in in NOMOUNT State

You lost your controlfile and the catalog. To restore the controlfile, you must know the DBID. Did you follow the advise to write down the DBID in a safe place? You didn't, did you? Well, what do you do next? Don't worry; you can still get the DBID from the header of the data files. Read on to learn how.

Tuesday, April 22, 2014

Restoring Controlfile When AUTOBACKUP Fail

Allow me to present the snapshot of a day from the life of John--the DBA at Acme Bank. On this particular day a database John manages crashed entirely and had to be restored from the backup. He takes regular (backupset) RMAN backups to tape. Since everything--including the controlfile--had crashed, John had to first restore the controlfile and then restore the database. The controlfile is always backed up with the backup database command. John was sure of that. However, restore controlfile from autobackup gave the error:
RMAN-06172: no AUTOBACKUP found or specified handle is not a valid copy or piece
Without the controlfile, the recovery was stuck, even though all the valid pieces were there. It was a rather alarming situation. Others would have panicked; but not John. As always, he managed to resolve the situation by completing recovery. Interested to learn how? Read on.

Thursday, April 17, 2014

Boston Oracle User Group Session: Oracle 12c Features You Should Know

Thank you for all those who attended the session, and braved it up to 10 PM. Much much appreciated.

Download the slides here, and scripts I used for the demos here.

As always, your feedback will be highly appreciated.

Friday, April 11, 2014

Collaborate14 Session: Cache Buffer Chains Demystified

Thank you all for coming to my session Cache Buffer Chains Demystified at Collaborate 14, especially for sticking around for a geeky topic like this to the very end. Much appreciated.

I was not aware that I would not be allowed to use my laptop; so I couldn't show all the demos I so carefully prepared. Please download the scripts and execute them yourself.

As promised, here are the materials I used in the session

The Slide Deck
The Whitepaper
The Scripts (this is a zip file; so right click and Save As ...)

Needless to say, your comments and feedback will be highly appreciated. And, yes, please don't forget to do the evaluation on the Collab Mobile App.

Thursday, April 10, 2014

Collaborate14 Session: The Art and Science of Tracing

Thank you all for coming to my session "The Art and Science of Tracing" at Collaborate 2014. As I mentioned, I prepared a full session even though this is supposed to be a quick tip. I hope you enjoyed it and get the value from the full presentation deck.

You can download

The slide deck
The scripts (this is a zip file. Right click and then Save As ...)

As always, your feedback will be immensely appreciated.

Wednesday, April 09, 2014

Collab14 Session Should You Drop Indexes in Exadata?

Thank you all those who attended my 8:30 AM session at Collaborate 14 "Should You Drop Indexes in Exadata" (Session 316). I will appreciate receiving your feedback and giving it on the IOUG website and mobile app.

Here are material I presented. I have the slides here; but I suggest you download the paper as it is more standalone in nature.