Return-Path: Received: from newsfeed.cts.com (newsfeed.cts.com [209.68.248.164]) by naude.co.za (8.11.2/8.11.2) with SMTP id g78FdNI11393 for ; Thu, 8 Aug 2002 11:39:23 -0400 Received: from fatcity.UUCP (uucp@localhost) by newsfeed.cts.com (8.9.3/8.9.3) with UUCP id IAA14959; Thu, 8 Aug 2002 08:39:04 -0700 (PDT) Received: by fatcity.com (26-Feb-2001/v1.0g-b71/bab) via UUCP id 004AF14A; Thu, 08 Aug 2002 07:58:39 -0800 Message-ID: Date: Thu, 08 Aug 2002 07:58:39 -0800 To: Multiple recipients of list ORACLE-L X-Comment: Oracle RDBMS Community Forum X-Sender: Ivan_Rivera@doh.state.fl.us Sender: root@fatcity.com Reply-To: ORACLE-L@fatcity.com Errors-To: ML-ERRORS@fatcity.com From: Ivan_Rivera@doh.state.fl.us Subject: RE: Shutdown abort Organization: Fat City Network Services, San Diego, California X-ListServer: v1.0g, build 71; ListGuru (c) 1996-2001 Bruce A. Bergman Precedence: bulk Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01C23EEB.F7CC4030" ------_=_NextPart_001_01C23EEB.F7CC4030 Content-Type: text/plain; charset="iso-8859-1" I've also just finished looking over this same stuff for a class I'm teaching and would like to add that in 8i after the rolling forward process and the database is opened, SMON does as you said and periodically will scan the rollback segments and roll transactions back. Meanwhile if a server process on behalf of a user encounters a block that it needs and that block was in an uncommitted transaction prior to the instance crash, it is not SMON that rolls the transaction back but the process itself that rolls the transaction back. But in 8i there's also has what's called On-Demand Parallel Rollback which means if the same scenario is happening (server process needs block that's in an inconsistent state) but the block needed was part of a large uncommitted transaction then what happens is that the server process will rollback only the block that it needs to perform it's transaction and hand over the rest of that long transaction to be rolled back to SMON and if that transaction has more than a 100 rollback blocks and fast_start_parallel_rollback is set, SMON will use recovery slave processes to aid in speeding up this large rollback. I guess what I'm trying to say is that it really depends on how large the uncommitted transaction is whether it's the server process itself that rolls it back or whether it just rollback the block it needs and then hands over the rollback job to SMON. Not trying to be picky over details just trying to add to the convo :). HTH. Ivan -----Original Message----- Sent: Thursday, August 08, 2002 10:48 AM To: Multiple recipients of list ORACLE-L Stefan Well, I finally found a good reason for studying for OCP! I would not have known this answer without being forced to study. It depends on your Oracle version. The Oracle 8i answer is: On startup, Oracle performs recovery, including rolling forward all transactions. Oracle then opens the database for production use. In the background, SMON continues to roll back transactions that were not committed when the database shut down. If a process needs a block that was involved in an uncommitted transaction, then SMON goes ahead and rolls back that transaction so the process doesn't have to wait. Dennis Williams DBA Lifetouch, Inc. dwilliams@lifetouch.com -----Original Message----- Sent: Thursday, August 08, 2002 7:58 AM To: Multiple recipients of list ORACLE-L Hi list stupid one: In case of a shutdown abort and startup, are the rollback activities discontinued after startup and the rollback segs are available again ? or not ? regards, Stefan -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Stefan Jahnke INET: Stefan.Jahnke@bov.de Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru@fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: DENNIS WILLIAMS INET: DWILLIAMS@LIFETOUCH.COM Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru@fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). ------_=_NextPart_001_01C23EEB.F7CC4030 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable RE: Shutdown abort

I've also just finished looking over this same stuff = for a class I'm teaching and would like to add that in 8i after the = rolling forward process and the database is opened, SMON does as you = said and periodically will scan the rollback segments and roll = transactions back.

Meanwhile if a server process on behalf of a user = encounters a block that it needs and that block was in an uncommitted = transaction prior to the instance crash, it is not SMON that rolls the = transaction back but the process itself that rolls the transaction = back.

But in 8i there's also has what's called On-Demand = Parallel Rollback which means if the same scenario is happening (server = process needs block that's in an inconsistent state) but the block = needed was part of a large uncommitted transaction then what happens is = that the server process will rollback only the block that it needs to = perform it's transaction and hand over the rest of that long = transaction to be rolled back to SMON and if that transaction has more = than a 100 rollback blocks and fast_start_parallel_rollback is set, = SMON will use recovery slave processes to aid in speeding up this large = rollback.

I guess what I'm trying to say is that it really = depends on how large the uncommitted transaction is whether it's the = server process itself that rolls it back or whether it just rollback = the block it needs and then hands over the rollback job to SMON.  = Not trying to be picky over details just trying to add to the convo :). = HTH. Ivan

-----Original Message-----
From: DENNIS WILLIAMS [mailto:DWILLIAMS@LIFETOUCH.COM]
Sent: Thursday, August 08, 2002 10:48 AM
To: Multiple recipients of list ORACLE-L
Subject: RE: Shutdown abort


Stefan
   Well, I finally found a good reason for = studying for OCP! I would not
have known this answer without being forced to = study.
   It depends on your Oracle version. The = Oracle 8i answer is:
   On startup, Oracle performs recovery, = including rolling forward all
transactions. Oracle then opens the database for = production use. In the
background, SMON continues to roll back transactions = that were not committed
when the database shut down. If a process needs a = block that was involved in
an uncommitted transaction, then SMON goes ahead and = rolls back that
transaction so the process doesn't have to = wait.

Dennis Williams
DBA
Lifetouch, Inc.
dwilliams@lifetouch.com


-----Original Message-----
Sent: Thursday, August 08, 2002 7:58 AM
To: Multiple recipients of list ORACLE-L


Hi list

stupid one: In case of a shutdown abort and startup, = are the rollback
activities discontinued after startup and the = rollback segs are available
again ? or not ?

regards,
Stefan



 
--
Please see the official ORACLE-L FAQ: http://www.orafaq.com
--
Author: Stefan Jahnke
  INET: Stefan.Jahnke@bov.de

Fat City Network Services    -- (858) = 538-5051  FAX: (858) 538-5051
San Diego, = California        -- Public Internet = access / Mailing Lists
---------------------------------------------------------------= -----
To REMOVE yourself from this mailing list, send an = E-Mail message
to: ListGuru@fatcity.com (note EXACT spelling of = 'ListGuru') and in
the message BODY, include a line containing: UNSUB = ORACLE-L
(or the name of mailing list you want to be removed = from).  You may
also send the HELP command for other information = (like subscribing).
--
Please see the official ORACLE-L FAQ: http://www.orafaq.com
--
Author: DENNIS WILLIAMS
  INET: DWILLIAMS@LIFETOUCH.COM

Fat City Network Services    -- (858) = 538-5051  FAX: (858) 538-5051
San Diego, = California        -- Public Internet = access / Mailing Lists
---------------------------------------------------------------= -----
To REMOVE yourself from this mailing list, send an = E-Mail message
to: ListGuru@fatcity.com (note EXACT spelling of = 'ListGuru') and in
the message BODY, include a line containing: UNSUB = ORACLE-L
(or the name of mailing list you want to be removed = from).  You may
also send the HELP command for other information = (like subscribing).

------_=_NextPart_001_01C23EEB.F7CC4030-- -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: INET: Ivan_Rivera@doh.state.fl.us Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru@fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).