RE: Temporary files and Quick i/o

Hi All,

Another correction. That error number has been changed to 7248 since Oracle8. I think I need a coffee!

@ Regards,
@ Steve Adams
@ http://www.ixora.com.au/
@ http://www.christianity.net.au/

-----Original Message-----
Sent: Friday, 18 May 2001 10:01
To: Multiple recipients of list ORACLE-L

Hi All,

OK, you're all correct. Tempfiles can be sparse (it seems to be platform specific). Nevertheless, I'm unclear why Veritas think that is it any more of a problem for Oracle to get ENOSPC from a sparse tempfile if it is a QIO file than otherwise. Presumably Oracle would just raise ORA-7376 in both cases. The instance would not fail because tempfile I/O is always done direct (not by DBWn). But if Veritas say not to do it, then I suppose that is good enough. The solution of course must be to use raw, rather than a filesystem based tempfile at all, for all the good reasons that would have pushed you toward QIO in the first place.

Johnson,

Could you please post the URL to the tip you mentioned so that I can fix it.

@ Thanks,
@ Steve Adams
@ http://www.ixora.com.au/
@ http://www.christianity.net.au/

-----Original Message-----
Sent: Friday, 18 May 2001 10:06
To: Multiple recipients of list ORACLE-L

I noticed this when I was playing with 9i. Regular tablespaces take long time to be created and temporary ones take nothing.

Here is the proof:

$ ls -l temp01.dbf
-rw-rw-r-- 1 oracle dba 209719296 May 17 18:55 temp01.dbf

$ du -k temp01.dbf
40968 temp01.dbf

$ ls -l users01.dbf
-rw-rw-r-- 1 oracle dba 26218496 May 11 20:27 users01.dbf

$ du -k users01.dbf
25608 users01.dbf

Regards,

Waleed

-----Original Message-----
Sent: Thursday, May 17, 2001 7:41 PM
To: Multiple recipients of list ORACLE-L

If you create tablespace like - create temporary tablespace <tablespace_name> ... <file_name>
created file will be sparse.

Alex Hillman

-----Original Message-----
Sent: Thursday, May 17, 2001 6:30 PM
To: Multiple recipients of list ORACLE-L

Hi Johnson,

I don't believe that tempfiles can be sparse (although I may be wrong) and I am
confident that datafiles cannot be. Maybe you should log a TAR with Oracle support to checkout whether tempfile can be sparse and just use datafiles until
then. Anyway, can you please post the URL to the tip you mentioned. While it is
the sort of thing I might say, I don't remember actually having said so.

@ Regards,
@ Steve Adams
@ http://www.ixora.com.au/
@ http://www.christianity.net.au/

-----Original Message-----
Sent: Friday, 18 May 2001 0:05
To: Multiple recipients of list ORACLE-L

Hi,

After reading Steve Adams' tip on making temp files quick io. I posed this question to Veritas as they had  told us not do so. The answer they give is the following.

Temporary datafiles should not be converted to quick i/o files. The following is an excerpt from the administrator's Guide: Tablespaces marked TEMPORARY can be sparse, which means that not all blocks in the file are allocated. Quick I/O files cannot be sparse, as Quick I/O provides a raw-type interface to storage. If a sparse file is converted to a Quick I/O file, the Oracle instance can fail if Oracle attempts to write into one of these unallocated blocks.

I would appreciate your thoughts on this?

Johnson Job

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