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Re: OFA and file extension naming conventions

From: Howard J. Rogers <>
Date: Thu, 25 Mar 2004 17:39:06 +1100
Message-ID: <40627e93$0$31904$>

"Snid" <snid_at_snider.sno> wrote in message news:c3tla8$tum$
> Hmmn, Ok.
> I guess I just look at tempfiles (files that exist in dba_temp_files)
> differently to datafiles (files that exist in dba_data_files) as you don't
> really need to back them up.

Not only do you not "need" to back them up, you can't back them up. You cannot issue 'alter tablespace X begin backup' commands, when the data files associated with that tablespace are known to be tempfiles.

So what, however? You can't take a datafile called system01.dbf offline or make system01.dbf read-only either.

Functionality is one thing, and the physics are something else. Physically, they're data files.

> Also, the fact that oracle segregates tempfiles from datafiles by using
> two tables from above makes me think of them as different so I thought
> maybe a different extension might be applicable.

The reason it did that, fundamentally, goes back to the inability to put a temp file into hot backup mode. A lot of people perform user-managed backups via scripts, and those scripts dynamically work out what to backup by looking at (for example) v$datafile. It obviously wouldn't do to have entries appearing in that view (and hence in the dynamically-created backup scripts) which will produce errors when 'begin backup' commands are attempted against them. Hence the need to separate them out from each other.

But again, just because I see table A, B, C and D when I query ALL_TABLES and only tables A & C when I query USER_TABLES doesn't mean that B and D aren't really tables.

> But yes, oracle does call tempfiles temporary datafiles or vice versa.
> "Howard J. Rogers" <> wrote in message
> news:40624469$0$31901$
> |
> | "Snid" <snid_at_snider.sno> wrote in message
> | news:c3tg0n$354$
> | > Under OFA it says that data files (datafiles) should end with a .dbf
> | > extension; however, it doesn't mention what temporary files
> | temp
> | > files) should end in.
> | >
> | > I don't think that tempfiles should end with a .dbf extension as they
> | aren't
> | > datafiles.
> |
> | Yes they are. What makes you think they're not? The contents of the
> | are different, for sure, in the sense that you don't care about it on a
> | long-term basis. But even then, they've got Oracle blocks inside them
> | headers and so on.
> |
> | The only difference between a "normal" data file and a temp file is that
> the
> | latter are created initially sparse (like when you touch a file in
> | But once people start using the file for sorts etc, then the thing gets
> | internally formatted exactly like any other data file would.
> |
> | So it's a data file, and it should get a dbf extension.
> |
> | Regards
> | HJR
> |
> |
Received on Thu Mar 25 2004 - 00:39:06 CST

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