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To improve performance, the DBA on site must check that the settings in the following table contain the correct values.
Table 6- 1 Additional DBA settings for the SQL Server-based PMDB
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The following table specifies the database block size prerequisite.
Table 6- 2 Oracle Server Database block size prerequisite
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The parameter values can be changed on a new and on an existing Oracle instance. The following tables describe the general and Oracle version specific parameters.
Table 6- 3 General parameters for the Oracle-based PMDB
| Parameter | Value | Improvement / Remarks |
|---|---|---|
| log_buffer | If the version <9.2.0.7, then the log_buffer = 3 MB, else the log_buffer= 16 MB. |
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| shared_pool_size | 1/4 of the physical memory. | The shared pool should not be too small (< 250 MB) or too large (>2 GB). |
log_checkpoint_timeout | 900 | |
open_cursors | 300 | Verify that you have enough open cursors for the application to execute. |
Processes | 300 | Verify that you have enough processes for the application to execute. |
db_writer_processes | Should be set according to the number of I/O devices you have for the database. | Improves I/O performance in cases of large I/O. Each writer is writing to different disks (improves loads, for example). |
Table 6- 4 Oracle 8i parameters
| Parameter | Value | Improvement / Remarks |
|---|---|---|
sort_area_size | (1/8th of the physical memory) / (concurrent users + 10), up to 6 MB. | For example: If you have 2 GB of Physical Memory and 90 users, then the calculation will be: (2 GB / 8) / 100 ~= 2.5 MB |
db_block_buffers | 1/3rd of the physical memory divided by the size of the | The given values help to keep the I/O wait of the PMDB queries low. |
Table 6- 5 Oracle 9i parameters
| Parameter | Value | Improvements / Remarks |
|---|---|---|
db_cache_size | Replaces parameter | |
pga_aggregate_target | 1/3rd of the physical memory. | |
workarea_size_policy | Auto | This parameter should be set to auto when we use the pga_aggregate_target parameter. |
| session_cached_cursors | 300 | |
DB-cache_advice | Verify that this parameter is set to | This parameter checks the work on the database and helps determine the recommended size of the Buffer pool. But this damages performance, so verify that it is on only for a short period. |
Table 6- 6 Oracle 10g parameter
| Parameter | Value | Improvement / Remarks |
|---|---|---|
sga_target | Automatic memory management. 1/4th of the physical memory. | Replaces the following parameters:
Verify that they are initialized with either 0 or the minimum value you need. |
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Table 6- 7 Rollback segment and redo log file settingsAnchor Table67 Table67
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The following table shows the default extents sizes.
Table 6- 8 Default extents sizes
| Tablespace | Size |
|---|---|
| Large table | 2 MB |
| Medium table | 512 KB |
| Small table | 80 KB |
| Large index | 1 MB |
| Medium index | 256 KB |
| Small index | 80 KB |
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