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Re:Your views on Quest - Shareplex

From: Rachel Carmichael <carmichr_at_hotmail.com>
Date: Tue, 29 May 2001 18:22:52 -0700
Message-ID: <F001.00312EF4.20010529180524@fatcity.com> 






Jim,



My apologies -- I misunderstood what you wrote. yes, pretty good legwork. 
Eyal used to be in NY and part of our user group here. I,
for one, miss him!



Rachel



>From: "Jim Hawkins" <jhawkins_at_primary.net>

>Reply-To: ORACLE-L_at_fatcity.com

>To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>

>Subject: Re:Your views on Quest - Shareplex

>Date: Tue, 29 May 2001 13:06:11 -0800

>

>Rachel,

>

>Sorry for the confusion - I meant that my sales rep got Eyal to reply to

>this, and then sent me the informative email.  I did not, however, know

>that I was getting it from the VP for Technology!  I guess I should have

>been really impressed with my sales reps leg-work!

>

>Jim

>

> > Jim,

> >

> > Um, if that is the Eyal I know, it's Eyal Aronoff and he's not exactly  

>a

> > "sales rep" for Quest but instead is the Senior VP for Technology and 

>the

> > person who developed Shareplex.

> >

> > Which means you got the best possible answer from the best possible

>source.

> > He's brilliant.

> >

> > Rachel

> >

> >

> > >From: "Jim Hawkins" <jhawkins_at_primary.net>

> > >Reply-To: ORACLE-L_at_fatcity.com

> > >To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>

> > >Subject: Re:Your views on Quest - Shareplex

> > >Date: Tue, 29 May 2001 11:01:21 -0800

> > >

> > >All,

> > >

> > >We are currently as customer of Quest Software using LiveReorg and

> > >Spotlight.  For those who don't know, LiveReorg is a combination of two

> > >existing Quest products, Space Manager and SharePlex.  I asked the 

>exact

> > >same question regarding the mining of redo logs of our Quest sales rep.

>I

> > >thought all would be interested in the reply.  It is a in-line reply to

>an

> > >Oracle MetaLink document.

> > >

> > >Jim Hawkins

> > >Lead SAPR/3 Oracle Database Administrator

> > >MEMC Electronic Materials, Inc.

> > >600 Pearl Drive

> > >St. Louis, MO  633376

> > >9636) 474-7832

> > >jhawkins_at_memc.com (work)

> > >jhawkins_at_primary.net (home)

> > >

> > 

> >++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

> > >

> > >  Doc ID:

> > >          Note:97080.1

> > >   Subject:

> > >          Extracting Data from Redo Logs Is Not A Supported Interface

> > >   Type:

> > >          BULLETIN


> > >   Status:

> > >          PUBLISHED


> > >

> > >  Content Type: TEXT/PLAIN

> > >  Creation Date: 22-JAN-2000

> > >  Last Revision Date: 17-FEB-2000

> > >  Language: USAENG

> > >

> > >   PURPOSE


> > >   -------

> > >

> > >   To explain why any extraction of data from redo logs is not 

>supported.

> > >

> > >   SCOPE & APPLICATION


> > >   -------------------

> > >

> > >Customers who are considering using Quest SharePlex for disaster

> > >recovery.

> > >

> > >

> > >   Extracting Data from Redo Logs Is Not A Supported Interface

> > >   

>----------------------------------------------------------------------

> > >

> > >    Quest SharePlex for Oracle replicates data to one or more other

>Oracle

> > >    instances. It attempts to use the information in the redo log to

> > >    replicate transactions remotely.

> > >

> > >    1) There is not sufficient information in the logs to logically

> > >    replicate transactions, so the data applied to the destination 

>system

> > >    may be different from the primary, and therefore inaccurate.

> > >

> > >Eyal: That is correct. A part of the SharePlex product goes back to the

> > >source database and completes the missing information. This is done 

>only

> > >for certain types of Update statements but is not nessasery for Inserts

>and

> > >Deletes.

> > >

> > >    2) Reading the redo log is not a supported interface. From the very

> > >    beginning, Oracle has changed redo log formats to support 

>functional

> > >    enhancements. We must therefore reserve the right to continue to 

>make

> > >    needed log format changes. For this reason, certification of any

>third

> > >    party product using this interface is not possible. Since this is 

>an

> > >    unsupported interface, the accuracy or completeness of the data in

>the

> > >    destination database can not be assured.

> > >

> > >Eyal: The power of the product is the direct result from reading the 

>raw

> > >log data. It is our core competency in Quest to understand and support

>the

> > >changing nature of the Oracle log. The reality is that between version

>7.0

> > >until 8.1.6 there where only minor changes to the log. Since we are a

>close

> > >partner with Oracle we get early releases of the software and we have 

>the

> > >chance to update the product as needed. So far this has never been an

>issue

> > >since most large production sites are running Oracle versions that are

> > >atleast 6 months to a year old.

> > >

> > >Regarding assurance to the completeness of the data, we do not expect

> > >Oracle to provide any assurance. Quest is the one that assures the

>content

> > >of the destination. Quest support has some of the best support experts 

>in

> > >the business. Any problem with the database content should be directed 

>to

> > >our support organization and not Oracle World Wide Support.

> > >

> > >    Likelihood of Occurrence

> > >    ~~~~~~~~~~~~~~~~~

> > >    Unknown. However, even a low likelihood is a concern for disaster

> > >    recovery (DR).  In disaster failovers, the remote server's database

>may

> > >be

> > >    the only viable copy.

> > >

> > >Eyal: Since Oracle uses the data in the log to perform database 

>recovery,

> > >all the information necessary to create a point in time image of the

> > >database exists in the log. However, we believe that SharePlex has a

>better

> > >chance to survive a disaster than even a database recovery.  This is

> > >because SharePlex only needs the data to recover a transaction while

>Oracle

> > >needs all changes present in the log, including index and rollback

>changes,

> > >to successfully recover a database. An index block corruption may 

>render

> > >the recovered database useless. History indicates that SharePlex can

> > >withstand most log corruptions and data block corruptions, while

> > >maintaining a viable live standby site.

> > >

> > >If the client is not a 100% sure, SharePlex provides a variety of

> > >mechanisms to periodically resync the standby database, including the

> > >ability to use a hot backup and 3rd party disk mirroring technologies -

>all

> > >of this without interruption to the main production site and without 

>the

> > >need to reactivate the replication.

> > >

> > >    Possible Symptoms

> > >    ~~~~~~~~~~~~~

> > >    The logs are applied logically, with most correctness checking

> > >performed

> > >    within the SQL generated by SharePlex, So SharePlex itself must

>alert

> > >the

> > >    user to any correctness problems. Absent SharePlex notification, 

>the

> > >    destination database likely will continue to work, leaving the user

>to

> > >    discover any incorrect data.

> > >

> > >

> > >Eyal: Conclusion, Oracle is still obligated to support the Oracle

>database

> > >on both the source and the destination. Quest will provide support for

>the

> > >content. (I am still waiting for the Oracle Sales rep to stand in front

>of

> > >a client and tell them that they do not need to pay for Support on that

> > >secondary database :-)

> > >

> > >I hope this helps.

> > >

> > >Eyal

> > >

> > >

> > > > Rao,

> > > >

> > > >     Somewhere on this list there is a fellow from Quest, I've seen

>his

> > >e-

> > >mail,

> > > > but can't remember who it is.  Therefore If I'm leading down a wrong

> > >path

> > >he can

> > > > correct.  Anyway, as I understand SharePlex it extracts the

>transactions

> > >from

> > > > the archived redo logs to replicate those transactions in another 

>DB.

> > >Pretty

> > > > slick, but redo logs are an Oracle company secret and therefore

>subject

> > >to

> > > > change by them at will with no forewarning to anyone.  Where can 

>that

> > >leave you,

> > > > out in the cold with a corrupt staging area?  Very possibly.  I know

>of

> > >another

> > > > product that is suppose to help you analyze performance problems, 

>but

>it

> > > > connects directly to the SGA bypassing the kernel.  Problem, it 

>works

>as

> > >long as

> > > > you don't change the starting address of the SGA and/or start paging

>it

> > >out of

> > > > memory.  Also, I had a demo copy of a product that supposedly re-

> > >organized the

> > > > internals of the database files, while Oracle was shut down.

>Problem: A

> > >VERY


> > > > big warning that if the DB would not restart after they finished,

> > >sorry!!

> > > >

> > > > Conclusion, any product that attaches to Oracle or it's files by 

>other

> > >than the

> > > > normal methods will not make it through the door.

> > > >

> > > > Dick Goulet

> > > >

> > > > ____________________Reply Separator____________________

> > > > Author: "Rao; Maheswara" <Maheswara.Rao_at_Sungardp3.com>

> > > > Date:       5/29/2001 9:16 AM

> > > >

> > > > List,

> > > >

> > > > My company is considering Quest - Shareplex.

> > > >

> > > > We are considering to use this in our dataware house.  Basically, 

>this

> > >will

> > > > pull all the transactions from OLTP database and populate staging

>area

> > >in

> > > > the dataware house.

> > > >

> > > > Could you please give your experiences and the pros and cons of this

> > > > Shareplex product.

> > > >

> > > > Thanks,

> > > >

> > > > Rao

> > > > --

> > > > Please see the official ORACLE-L FAQ: http://www.orafaq.com

> > > > --

> > > > Author: Rao, Maheswara

> > > >   INET: Maheswara.Rao_at_Sungardp3.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_at_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:

> > > >   INET: dgoulet_at_vicr.com

> > > >

> > > > Fat City Network Services    -- (858) 538-5051  FAX: (858) 538-5051

> > > > San Diego, California        -- Public Internet access / Mailing 

>Lists

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> > > > also send the HELP command for other information (like subscribing).

> > > >

> > > >

> > >

> > >

> > >--

> > >Jim Hawkins

> > >Lead SAPR/3 Oracle Database Administrator

> > >MEMC Electronic Materials, Inc.

> > >600 Pearl Drive

> > >St. Louis, MO  633376

> > >9636) 474-7832

> > >jhawkins_at_memc.com (work)

> > >jhawkins_at_primary.net (home)

> > >

> > >--

> > >Please see the official ORACLE-L FAQ: http://www.orafaq.com

> > >--

> > >Author: Jim Hawkins

> > >   INET: jhawkins_at_primary.net

> > >

> > >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_at_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).

> >

> > _________________________________________________________________

> > Get your FREE download of MSN Explorer at http://explorer.msn.com

> >

> > --

> > Please see the official ORACLE-L FAQ: http://www.orafaq.com

> > --

> > Author: Rachel Carmichael

> >   INET: carmichr_at_hotmail.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_at_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).

> >

> >

>

>

>--

>Jim Hawkins

>Lead SAPR/3 Oracle Database Administrator

>MEMC Electronic Materials, Inc.

>600 Pearl Drive

>St. Louis, MO  633376

>9636) 474-7832

>jhawkins_at_memc.com (work)

>jhawkins_at_primary.net (home)

>

>--

>Please see the official ORACLE-L FAQ: http://www.orafaq.com

>--

>Author: Jim Hawkins

>   INET: jhawkins_at_primary.net

>

>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_at_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).






Get your FREE download of MSN Explorer at http://explorer.msn.com


-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.com
-- 
Author: Rachel Carmichael
  INET: carmichr_at_hotmail.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_at_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).


Received on Tue May 29 2001 - 20:22:52 CDT












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