Saturday, June 27, 2009

Undo and Temporary Tablespace Setup

Undo Management

The database releases certified for use with Oracle Applications Release 12 only support the use of system managed undo (SMU).

SMU is more efficient than traditional rollback segments and reduces the possibility of “snapshot too old” (ORA-1555) errors.

TEMP Tablespace

It is recommended that the temporary tablespace for Oracle Applications users be created using locally managed temp files with uniform extent sizes of 128K.

The 128K extent size is recommended because numerous modules, such as Pricing and Planning, make extensive use of global temporary tables which also reside in the temporary tablespace.

Since each user instantiates a temporary segment for these tables, large extent sizes may result in space allocation failures.

Following is an example of creating a locally managed temporary tablespace with temp files:

SQL> drop tablespace temp;
SQL> create temporary tablespace temp
tempfile '/d2/prodr12/dbf/temp01.dbf' size 2000M reuse
extent management local
uniform size 128K;

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