The SAP System for the Oracle database comes with a standard initialization profile for the database parameters:
· UNIX
OS> <ORACLE_HOME>/dbs/init<DBSID>.ora
· Windows
OS> <ORACLE_HOME>\database\init<DBSID>.ora
For example (UNIX):
/oracle/C11/dbs/initC11.ora
This profile contains the default parameter settings recommended for the SAP System. Copy this standard profile so that you can access the original parameters, if necessary.
All parameters that specify paths and file names are operating system-specific. These parameters have to be adjusted to agree with your operating system. When possible, however, SAP recommends that you retain the default path and file descriptions in the system. Make the appropriate changes to your operating system instead.
?is the Oracle placeholder for $ORACLE_HOME.
Parameter |
SAP recommendation |
control_files |
|
log_archive_dest |
OS> ?/oraarch/<DBSID>arch, where ?/oraarch can be a soft link to a
separate disk or a separate mount point. |
background_dump_dest |
OS> ?/saptrace/background Directory for database trace and database ALERT files. If you have serious database problems, you must analyze the information in the ALERT and trace files. |
user_dump_dest |
OS> ?/saptrace/usertrace Directory for user trace files. |
The following lists a selection of RAM-dependent tuning parameters. For more information, see the Oracle documentation.
Parameter |
Settings |
ram (unit: MB) Portion of physical RAM that you want to reserve for the system. |
One system installed on one host: ram = 1.0*RAM Two systems installed on one host: ram = 0.5*RAM |
rating Proportion of RAM taken up by the database and the SAP System |
Default: rating=0.25 (25% of RAM reserved for the database, 75% for the SAP System) Database-only server: rating=0.8 (80% of RAM is reserved for the database) If ram<RAM*0.8: rating=1.0 (100% of RAM is reserved for the database) |
db_block_size db_block_size |
Operating system-specific, default: 8192 |
The parameters ram, ratingand db_block_size are taken into account when calculating the following tuning parameters:
Parameter |
Determination of its value |
shared_pool_size db_block_size |
shared_pool_size=ram*rating*0.4*1024*1024 The factor 0.4 means that shared_pool_size occupies 40% of
the calculated SGA. |
db_block_buffers db_block_size |
db_block_buffers=ram*rating*0.6*1024*1024/db_block_size The factor 0.6 means that db_block_buffers occupies 60% of the calculated SGA. |
log_buffer db_block_size |
Default: log_buffer=327.680 Part of the SGA, which is very small when compared with shared_pool_size and db_block_buffers. |
row_cache_cursors Number of cursors used for selecting lines from the data dictionary. |
row_cache_cursors= 300, if ram>=256 200, if ram<256 100, if ram<128 |