RE: redo and undo
Date: Mon, 5 Mar 2012 10:30:59 -0600
I'm not concern on measuring the amount of redo generated. I was wondering why the log miner did not show the redo for the undo and index blocks.
Trying to learn how it all works.
From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of David Fitzjarrell
Sent: Monday, March 05, 2012 10:16 AM
To: cure_at_austin.rr.com; Oracle-L_at_freelists.org Subject: Re: redo and undo
LlogMiner reports the SQL statements to redo or undo the change; it does not
report the amoujnt of redo generated for the operation specified. You would
need to query the data dictionary for such statistics ( The v$mystat view
would show the redo stats for your current session; query v$mystat, run the
statement then query v$mystat again and take the difference -- you should
see what you're expecting to see in terms of redo generation. A query to do
select n.name, m.value
from v$mystat m join v$statname n on (n.statistic# = m.statistic#) where n.name like 'redo%';
From: Paul Harrison <cure_at_austin.rr.com> To: Oracle-L_at_freelists.org
Sent: Monday, March 5, 2012 8:32 AM
Subject: redo and undo
Let's say I run the following command... insert into cure.thecure (firstname ,lastname) values('oracle','11gr2'); The table has an index on the lastname column...
Using Log Miner, There is redo and undo for the table block. The book I'm
reading said that all 3 types of blocks (undo, table, index) have generated
redo to protect them. I'm lost here because I do not see redo for the index
block or the undo block. I only see redo and undo for the table block.
Any help is greatly appreciated.
Log Miner info below:
INSERT insert into "CURE"."THECURE"("FIRSTNAME","LASTNAME") values ('oracle','11gr2'); delete from "CURE"."THECURE" where "FIRSTNAME" 'oracle' and "LASTNAME" = '11gr2' and ROWID = 'AAARlCAAEAAAAIMAAB';
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