Comments for Irrelevant thoughts of an oracle DBA

Comment on linux / unix kernel parameters follow-up by dhoogfr

dhoogfr — Tue, 24 Jun 2008 06:51:22 +0000

Muthu,

The limit you are experiencing is not a memory limit, but a build in limitation of oracle XE.
Oracle XE is a free version of the oracle database and therefore has been limited to a maximum of 4 GB in size.
The only real option you have if you need more then 4GB of data is to upgrade to a full oracle version (I think the cheapest version would be oracle standard edition one).

Check following links for more information about oracle express:

http://www.oracle.com/technology/products/database/xe/index.html
http://www.oracle.com/technology/products/database/xe/pdf/dbxe_datasheet.pdf

Comment on linux / unix kernel parameters follow-up by Muthu

Muthu — Tue, 24 Jun 2008 06:42:50 +0000

Hi
I had installed 10g XE, I have created a new user in th DB while importing the dump its gives the error
can’t import more than 4GB.( Alredy data files are around 4GB).
plz give any solution to resolve the problem.

Muthu

Comment on bugs introduced via patches by Sefa Şahin

Sefa Şahin — Sun, 15 Jun 2008 09:00:11 +0000

good docs. thanks

Comment on Oracle VM: a first installation attempt by Ramon

Ramon — Tue, 27 May 2008 19:38:32 +0000

Thanks for the iso tip, you saved may day. :)

Comment on Oracle VM: a first installation attempt by janos ujvari

janos ujvari — Tue, 13 May 2008 07:54:33 +0000

Thanks for this description it was very helpful.
Janos Ujvari
May, 13. 2008.
Subotica, Vojvodina

Comment on fun with frequenty based histograms by dhoogfr

dhoogfr — Thu, 17 Apr 2008 20:51:42 +0000

Volker,

But then how would oracle know that the table has grown?
If the dba_tables.num_rows is not changed, the extrapolated result will not change if the table grows (or shrinks)

The only reason i can think of why oracle stores the sample result and not the extrapolated numbers, is that it is now easier to go behinds the cbo’s back to change the expected cardinality (by changing the num_rows).

In theory you could thus gather histograms once and then just change the num_rows to cope with the growth of the table.
But I’m not sure if this is something I would advice.

Comment on fun with frequenty based histograms by Volker Kleinschmidt

Volker Kleinschmidt — Thu, 17 Apr 2008 17:08:55 +0000

Hmm, if you add more records into the table after stats were gathered, there is a somewhat imprecise but nevertheless sensible assumption that they would be distributed similarly to the existing records. So if you don’t store the extrapolated numbers but the actual sample results, and extrapolate on the fly, then the CBO can make sensible decisions even if the table has grown 100%.

Of course, regathering stats is always recommended when there’s dramatic change in data, but the method used by Oracle still strikes me as more robust since it can deal with such data change for a while with (hopefully) only slightly degraded accuracy. If it stored the extrapolated results for cardinality, even relatively small changes to the data would make those stored results significantly wrong.

Comment on October cpu patch by dhoogfr

dhoogfr — Wed, 09 Apr 2008 16:06:43 +0000

Dion,

The problem I had was that the oracle user was no longer capable of writing the lockfile to the locks directory, not the lockfile itself.

Comment on rman backup to tape when you don’t have a tape by dhoogfr

dhoogfr — Wed, 09 Apr 2008 15:58:07 +0000

yogesh,

I did not know that, thanks for the tip

Comment on October cpu patch by Dion

Dion — Wed, 09 Apr 2008 14:49:51 +0000

Try Doc ID: Note:73123.1

I just removed the lock file.