Definition
The SAP System for the Oracle database comes with a standard initialization profile for the database parameters:
OS> <ORACLE_HOME>/dbs/init<DBSID>.ora
For example:
/oracle/C11/dbs/initC11.ora
Use
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.
Structure
Operating System-Specific Parameters
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 |
See Mirroring the Control File. |
log_archive_dest |
OS> ?/saparch/<DBSID>arch, where ?/saparch can be a soft link to a separate disk or a separate mount point.See Setting Up Archiving. |
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/background Directory for user trace files. |
Tuning Parameters
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 (unit: bytes) size of the Oracle database blocks |
Operating system-specific, default: 8192 |
The parameters
ram , rating and db_block_size are taken into account when calculating the following tuning parameters:
Parameter |
Determination of its value |
shared_pool_size db_block_size (unit: bytes) buffer size for parsed SQL statements in the Oracle System Global Area (SGA) |
shared_pool_size=ram*rating*0.4*1024*1024 The factor 0.4 means that shared_pool_size occupies 40% of the calculated SGA.shared_pool_size=20.971.520 if the value calculated using the formula above is lower than 20971520 Bytes. |
db_block_buffers db_block_size (unit: blocks) buffer size for data blocks and index blocks in the Oracle SGA |
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 (unit: bytes) buffer size for redo log entries in the Oracle SGA |
Default: log_buffer=327.680Part 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 ABAP Dictionary. |
row_cache_cursors= 300 , if ram>=256200 , if ram<256100 , if ram<128 |