Re: what's xidsql and ubasqn in v$transaction?

From: Jonathan Lewis <jonathan_at_jlcomp.demon.co.uk>
Date: Tue, 30 May 2006 21:30:04 +0100
Message-ID: <xrGdnWJwWcPZNuHZnZ2dnUVZ8qidnZ2d@bt.com>

The slots in the transaction table in the undo segment header are continuously being reused. Each time a slot it re-used, its sequence number (xidsqn) goes up.

Similarly, undo blocks are re-used (though it takes more time to get round to re-using them than transaction slots). Each time an undo block is "newed" and reused, its sequence number UBASQN goes up.

-- 
Regards

Jonathan Lewis
http://www.oracle.com/technology/community/oracle_ace/ace1.html#lewis

The Co-operative Oracle Users' FAQ
http://www.jlcomp.demon.co.uk/faq/ind_faq.html

Cost Based Oracle: Fundamentals
http://www.jlcomp.demon.co.uk/cbo_book/ind_book.html


<niy38_at_hotmail.com> wrote in message 
news:1149016152.331841.200160_at_i40g2000cwc.googlegroups.com...


> XIDSQN          Wrap of the entry

> UBASQN          Sequence no of last entry

>

> don't understand what that mean.

>

Received on Tue May 30 2006 - 15:30:04 CDT