New Index on 550 Gb table - suggstions please

Question

Hello friends,
i have to create a new Index in Oracle 11g db for a table of size around 550GB. please give me your expert suggestions.
I have checked SAP Note 334224 and plan to do with SQl
Create the index using SQLPLUS with the following command:
create index <index name> on <table name> ( <field1, field2, ...> )
nologging tablespace <tablespace name>
parallel (degree <number>)
..........online;
questions:
1. How much Temp tablespace is required for this.
2. Any suggestions for parallel (degree <number>) parameter.. we have 4 CPU.
3. Should i use parameter nologging or complete nologging tablespace <tablespace name> ? does it have any problems ? Database is in archivelog mode.. and is it required for complete tablespace ?
thanks
ashish

Answer 1

ashish vikas wrote:
> 1. How much Temp tablespace is required for this.
> 2. Any suggestions for parallel (degree <number>) parameter.. we have 4 CPU.
> 3. Should i use parameter nologging or complete nologging tablespace <tablespace name> ? does it have any problems ? Database is in archivelog mode.. and is it required for complete tablespace ?
Hi,
1) I think, when using parallel DDL, it always uses direct path i/o and then it goes directly to temp.
Never saw anything different when doing this. Always had "direct path write temp" as wait event in ST04 during creation.
Check the index name on DB level in the development system. If the tablename is long, the activation
of the transport imported later might change the name to make it fit into the namespace and therefore
might shorten some names.
I e. ODS-Table name
/BIC/ABCD_GH_JKL
Index 010
leads to an index name
/BIC/ABCD_GH_JKL10
on DB level. It depends on the length of the table name. In this case /BIC/ABCD_GH_JKL~010 would be too long.
If you plan to import the corresponding transport afterwards, make sure, that the index name fit the one that
will be generated on DB level. Otherwise you might get an error that this fieldlist is already indexed.
Keep in mind that allthough you create online, it requires a short exclusive lock to start. Just had that last week.
My statement waited about 25 minutes in ST04 before it kicked off the PQ slaves.
2) If you are nearly alone, and your CPUs are speedy,  I'd go parallel 8. This will create 16 PQ slaves for the statement,
8 beinig busy pumping data to temp, 8 waiting until these are ready and then doing reading temp and writing target.
If there is activity on the system, 2 or 4 might be a better choice.
3) NEVER set the TS nologging. But yes, you can use NOLOGGING in the create statement. Check the brrecover docu.
It is capable of handling NOLOGGING indexes after a restore, but in general it should be avoided,
esp. if the index is not re-created all the time (as i.e. in BW dataloads).
Volker
Oh, and as for the discussion of temp files:
I thought since oracle 10g you can simply drop empty datafiles and tempfiles.
So I'd extend PSAPTEMP as needed and simply drop the files back out afterwards.
Keep in mind these are SPARSE Files that may not use the shown space in the filesystem until utilized!
I mind I have read somewhere that change of a schema owner is a development request for version 12.
Edited by: Volker Borowski on Sep 27, 2011 8:23 PM