RE: rollback segments during export

Jared et al,

My understanding could be flawed, but I think that setting 'CONSISTENT=Y' just adds a 'SET TRANSACTION READ ONLY' to the entire export process and thus ensures that all subsequent queries read all tables as of the time the export started. Keep in mind that an export just does a 'select * from <table_after_table_after_table> along with a lot of other DDL generation. This is the reason you can expect ORA-01555 errors when trying to read from a wrapped-around or shrunk rollback segment in the case a read-consistent read is required....

I hope I am making sense here....

John Kanagaraj
Oracle Applications DBA
DB Soft Inc
Work : (408) 970 7002

Listen to great, commercial-free christian music 24x7x365 at http://www.klove.com

• The opinions and facts contained in this message are entirely mine and do not reflect those of my employer or customers **

>-----Original Message-----
>From: Jared Still [mailto:jkstill_at_cybcon.com]
>Sent: Sunday, September 30, 2001 12:40 AM
>To: Multiple recipients of list ORACLE-L
>Subject: Re: rollback segments during export
>
>
>
>Chris,
>
>> Just because there is a PK/FK between tables, it does not
>mean they will be
>> exported in the same transaction. And thus, possibly out of sync.
>
>I didn't say there was. My implication was that your
>tables would get out of sync. Setting 'consistent=y'
>won't prevent that:
>
>: If you specify CONSISTENT=N (the default), each table is
>usually exported
>: in a single transaction. However, if a table contains nested
>tables, th
>
>Now it *could* be that I'm misreading the docs. It' been known
>to happen, but that sentence says to me that each table is
>exported as part of a single transaction.
>
>Anyone have proof to the contrary? The tech writer is being
>rather ambigous, at least I think so.
>
>Jared
>--
>Please see the official ORACLE-L FAQ: http://www.orafaq.com
>--
>Author: Jared Still
> INET: jkstill_at_cybcon.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: John Kanagaraj
  INET: john.kanagaraj_at_hds.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).