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Home -> Community -> Mailing Lists -> Oracle-L -> RE: Is there a transaction number?
the SCN number is maintained for serialization purposes, consisting of an SCN
base and an SCN wrap, assigned at transaction commit time. these SCN numbers are
kept in the data block headers, and are crucial for correct database recovery.
if you need undo related to transactions, you need a transaction identifier,
consisting of three components:
undo segment number, transaction table slot, and wrap number. these values can
be found in the ITL entries of data blocks. however, this information is
overwritten as soon as ITL entries in data blocks are reused; also, transaction
table entries are reused all the time.
why would Oracle keep track of transactions, once they are committed?
(apart from read consistency purposes, of course)
kind regards,
Lex.
From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On
Behalf Of Sandeep Dubey
Sent: Thursday, September 22, 2005 21:35
To: oracle-l_at_freelists.org
Subject: Is there a transaction number?
How does Oracle keep track of transactions? Is there a unique transaction number
(not scn) assigned to each transactions in the life of database. How can I get
that number. I was looking into V$TRANSACTION but could not figure out what is
that unique transaction identifier.
Thanks
Sandeep
-- http://www.freelists.org/webpage/oracle-lReceived on Thu Sep 22 2005 - 14:52:34 CDT
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