RE: Hot Backup Issue

That
makes sense, I just wanted to check :0) And of course, transactions in other tablespaces would be writing redo as normal. The overall level of redo generated would surely be less, tho'? Because say you had 5 tablespaces and put them all into hotbackup mode. Then the 5th tablespace would be writing full blocks to the redo log for all the time it took to copy the datafiles of the first 4, rather than for just the time it took to copy itself if you only put tablespaces into backup mode while they were actually having their datafiles copied? And when recovering, Oracle doesn't mind that some redo information will be full blocks, and some not, if a transaction spans multiple tablespaces, one of which was in hotbackup mode and the rest not when the transaction was committed?
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<SPAN
class=697573113-02102001>Thanks,
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<SPAN
class=697573113-02102001>g

  <FONT face=Tahoma
  size=2>-----Original Message-----From: Hallas John   [mailto:John.Hallas_at_btcellnet.net]Sent: Tuesday, October 02, 2001   1:45 PMTo: Multiple recipients of list ORACLE-LSubject:   RE: Hot Backup Issue
  Guy, I would have thought 2) was best   as you are reducing the concurrency (I think that is the right word) of redo   log activity.
  As each tablespace is in backup mode it writes the full block   to the redo log when any changes are made. On the assumption that all   tablespaces are being written (albeit infrequently) during the period of hot   backup it is better to alter each tablespace, copy it then alter online again   so that only 1 tablespace at a time is having full blocks of changed data   writing to the redo logs.
  The overall level of redo will be the same but contention (ah   ha  - better word) will be reduced
  John
  -----Original Message----- From: Guy
  Hammond [<A
  href="mailto:guy.hammond_at_avt.co.uk">mailto:guy.hammond_at_avt.co.uk]   Sent: 02 October 01 12:15 To:
  Multiple recipients of list ORACLE-L Subject: RE: Hot   Backup Issue
  Hello,
  Slightly unrelated question... is it better to (in pseudo   code) :
  1)
  for each tablespace loop
        put tablespace in

  backup mode end loop
  for each datafile in the database loop
        copy data

  file end loop
  for each tablespace loop
        put tablespace in

  normal mode end loop
  or 2)
  for each tablespace loop
        put tablespace in

  backup mode         <FONT
  size=2>for each datafile in this tablespace loop
       
        copy data file
        end loop
        put tablespace in

  normal mode end loop
  What I'm doing is (2), but I notice that Rajesh is doing (1).   What are the pros and cons of each approach? (I'll   probably use RMAN at some point, anyway :0) ).   

  Cheers,
  g   --
  Please see the official ORACLE-L FAQ: <A   href="http://www.orafaq.com" target=_blank>http://www.orafaq.com

• Author: Guy Hammond   INET: guy.hammond_at_avt.co.uk Fat City Network Services    -- (858) 538-5051  FAX: (858) 538-5051 San Diego, California        -- Public Internet access / Mailing Lists <FONT size=2>-------------------------------------------------------------------- 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). <FONT size=3>**********************************************************************This email and any attachments may be confidential and the subject oflegal professional privilege. Any disclosure, use, storage or copyingof this email without the consent of the sender is strictly prohibited.Please notify the sender immediately if you are not the intendedrecipient and then delete the email from your inbox and do notdisclose the contents to another person, use, copy or store theinformation in any medium.**********************************************************************