If you have to convert in place, do it. But let's examine things a bit more closely first. You say you have tablespaces sized from 5 GB to 60 GB and you don't have much freespace as a buffer. Do you have 60 GB buffer? If so, you're home free. Create a new LMT, move the objects from the DMT to the new LMT, drop the old tablespace including contents and delete the data files.
You don't have 60 GB free space? Create a map of where each object resides in the data files which make up the DMT. Create a new LMT tablespace with as many files as you can fit in your free space.. Move the object from DMT to LMT that'll allow you to shrink the data files in the DMT as much as possible. Now you have more free space. Continue adding data files to the LMT as needed as you move each object and shrink the DMT's data files. When the DMT is empty, drop it including contents and delete the data files. That's one DMT converted. Now on to the next ones. If you're just embarking on conversion to LMT and permanent rollback segments, convert your rollback tablespaces first. You'll get a performance boost from not having to go through the ST enqueue when extending or shrinking your rollback segments. Replace your temporary tablespaces with ones consisting of temp files then edit your hot backup script to stop backing up your temporary tablespaces. Your SA will love you for it. Make sure you dump your control file to trace when you change your backup script. ----- Original Message ----- To: "Multiple recipients of list ORACLE-L" <[EMAIL PROTECTED]> Sent: Tuesday, October 29, 2002 11:48 AM This is what we have in mind. For the partitioned tables that are going to have the 'rotation' logic, we will convert them to LMT when they become empty. We drop the 'oldest' partition and create a new one for next month. This will be carried out every month. Partition for November data is empty now and is being converted to use LMT as of this week; Next month we will do the same for December partition; This way, we would convert all our 5 CALLDETAIL tablespaces to use LMT in 5 months time. Now, for other tablespaces that contain data and indexes, we need to decide whether we should create corresponding LMT tablespaces and move the existing objects to it or change them using the procedure that Oracle recommends; Some of these tablespaces are sized anywhere from 5Gb to 60Gb and we do not have much of freespace as buffer. Our database size is about 1.2 tera bytes. Also for this we might have to ask for a bigger maintenance window which will be hard to get. So we are toying up with the idea of converting them from DMT to LMT using 'in place' mechanism and rebuild the tables/indexes eventually as time permits. Obviously, we are not trying cause any outage knowingly. Hence these questions to the forum. Thanks, Govind -----Original Message----- Sent: Tuesday, October 29, 2002 8:49 AM To: Multiple recipients of list ORACLE-L Govind - I agree with Tom. Since you phrased your original question asking for those who had done the conversion, the silence was your answer. If you had also asked for replies from those who had decided to build new tablespaces and convert the data ourselves, then more of us could have replied. My reason for not using the conversion utility has to do with the smell test. After you've been a DBA for awhile, you realize you have limited time and you lose your eagerness to pursue things that will eat up enormous amounts of time and come to nothing. In my situation, I was able to move a table at a time to LMT as time permitted, and somehow I felt that the resulting data situation would be better. I believe some of the new nologging options may allow you to perform this while the table is still available for DML. When first introduced, the conversion routines had some bugs. I don't think the conversion routines are bad today, so they may work just fine. Dennis Williams DBA, 40%OCP Lifetouch, Inc. [EMAIL PROTECTED] -----Original Message----- Sent: Tuesday, October 29, 2002 12:34 AM To: Multiple recipients of list ORACLE-L I tried having Oracle convert DMT to LMT out a few times on 10 GB tablespaces. Whether or not that's a lot of data depends on you. Worked like a champ. And this was in the early days of LMT. People who pay a lot of attention to the internals will warn you that converting a DMT to LMT is not optimal. Your bitmaps wind up at the end of the files instead of the headers. I've read posts here and elsewhere where people worried about the same issues as they did with DMT. They wanted to limit the number of extents segments grew to by creating tablespaces with different sized fixed extents. A DBA I worked with pointed out how very easy and quickly things worked with letting Oracle automatically size the next extent. I've gone that way whenever possible and have never regretted it. I've not done a rigorous benchmark but can tell you from casual observation dropping an object with lots of extents doesn't happen in the blink of an eye but doesn't lock out all other space allocation as UET/FET weren't constantly in use and the ST enque wasn't locked for exclusive use. It's prudent to follow Oracle's recommendations if conditions permit. Create a new LMT and move your data to it. ----- Original Message ----- To: Multiple <mailto:ORACLE-L@;fatcity.com> recipients of list ORACLE-L Sent: Monday, October 28, 2002 8:43 PM I am reposting this. Has anyone tried to convert a dictionary managed table space containing lots of data to locally managed? We have tried this out successfully on empty table spaces or created a new LMT tablespace and moved the existing objects to it. Thanks, Govind -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: DENNIS WILLIAMS INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (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: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (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: Tom Pall INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (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).
