Re: Full export and sequence behaviour in 8i

From: Dan Norris <dannorris_at_dannorris.com>
Date: Mon, 16 Mar 2009 09:31:15 -0500
Message-ID: <49BE62B3.7040208_at_dannorris.com>

I agree, with crashes, lots of Bad Things can happen. I'm not ignoring that, but I took your original message to mean that in normal operation sequence use can result in gaps. We don't disagree...and it's always good to think of the potential failures. My devil's advocate was turned off for a while. I cranked it back up now, so we're all nodding along over here.

Thanks for the others that replied similarly, too.

Dan

Robert Freeman wrote:

I've seen at least one case of an instance crash causing loss of a sequence in nocache mode.
This was a while back (9i) and perhaps it was a bug (though one was never filed). 
Based on this experience, I don't trust sequences if I *absolutley* require no gaps.
When you end up looking at business requirements, this is rarely the case in fact, but generally assumed. 
So, often it's not really an issue.

Your experience may be different than mine, and I certainly have no desire to disseminate misinformation.

Cheers!

RF



 Robert G. Freeman
Author:
OCP: Oracle Database 11g Administrator Certified Professional Study Guide (Sybex)
Oracle Database 11g New Features (Oracle Press)
Portable DBA: Oracle  (Oracle Press)
Oracle Database 10g New Features (Oracle Press)
Oracle9i RMAN Backup and Recovery (Oracle Press)
Oracle9i New Features (Oracle Press)
Other various titles out of print now...
Blog: http://robertgfreeman.blogspot.com 
The LDS Church is looking for DBA's. You do have to be a Church member in
good standing. A lot of kind people write me, concerned I may be breaking
the law by saying you have to be a Church member. It's legal I promise! :-)



----- Original Message ----
From: Dan Norris <dannorris_at_dannorris.com>
To: Robert Freeman <robertgfreeman_at_yahoo.com>
Cc: "hkchital_at_singnet.com.sg" <hkchital@singnet.com.sg>; "adar666@inter.net.il" <adar666@inter.net.il>; Oracle L <oracle-l@freelists.org>
Sent: Sunday, March 15, 2009 6:46:08 PM
Subject: Re: Full export and sequence behaviour in 8i

Hi Robert,

Never is a word I don't see too often. I think a "nocache order" sequence is better and more reliable than any other method I've seen. What approach would you use instead to have a no-gap list of numbers guaranteed?

Dan

Please excuse my typos, I sent this from my iPhone.

On Mar 15, 2009, at 7:09 PM, Robert Freeman <robertgfreeman_at_yahoo.com> wrote:

  

You should never use a sequence if what you want is an assured serial number with no gap.
There are a number of ways to loose a number in a given sequence.....

RF


Robert G. Freeman
Author:
Blog: http://robertgfreeman.blogspot.com
OCP: Oracle Database 11g Administrator Certified Professional Study Guide (Sybex)
Oracle Database 11g New Features (Oracle Press)
Portable DBA: Oracle  (Oracle Press)
Oracle Database 10g New Features (Oracle Press)
Oracle9i RMAN Backup and Recovery (Oracle Press)
Oracle9i New Features (Oracle Press)
Other various titles out of print now...
The LDS Church is looking for DBA's. You do have to be a Church member in
good standing. A lot of kind people write me, concerned I may be breaking
the law by saying you have to be a Church member. It's legal I promise! :-)



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-- http://www.freelists.org/webpage/oracle-l Received on Mon Mar 16 2009 - 09:31:15 CDT