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The results should be that the " Extent Scan Fragmentation " is less than 50 and the " Logical Scan Fragmentation " is low; otherwise, it will damage the index scans.
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Info |
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Be aware that the index and the table will not be available is unavailable during the rebuild. |
Backing up the database and creating archiving
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If you choose the simple recovery mode for the database (the transaction log can be deleted after a commit or checkpoint), the recovery will not be able to cannot work to a point in time, but only to the backup time.
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If you do not create a backup, information will be is lost when you have a database crash and you will not be able to cannot recover data.
Additional DBA settings for an SQL Server-based PMDB
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Parameter | Value | Improvement | ||
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db_block_size | Minimum 8 KB (16 KB recommended) | This value defines the Oracle block size. The block size is set when creating the database and cannot be changed afterwards. A value of at least 8 KB ensures that the PMDB can perform smoothly. A lower value may cause serious performance problems. If you are installing on a legacy database, verify that the database block size is 8 KB or higher. If not, try to install the PMDB on a different Oracle instance.
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Required INIT.ORA changes
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Parameter | Value | Improvement / Remarks |
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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. |
Table 4 Oracle 9i parameters
Parameter | Value | Improvements / Remarks | |
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session_cached_cursors | 300 | DB-cache_advice | Verify that this parameter is set to |
Parameter | Value | Improvement / Remarks | |
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 ison only for a short period. |
Table 5 Oracle 10g parameter
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. |
INIT.ORA example
The following is an example of the init.ora
file for an Oracle 12.2 instance.
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The PMDB holds information for up to 3 three years by default. If you want to backup this information, you should enable the Redo log archiving, and create a backup using RMAN. For more information, refer to the official Oracle Backup and Recovery documentation. If you do not create a backup, information will be lost when you have a database crash and you will not be able to recover data. If you create a backup without using the archive mode, you will be able to recover data to the time of the backup. All new operations (after the logs were archived) will be lost.
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To enable Automatic Undo Management (AUM), you must create a new tablespace and set the init.ora
parameters. For additional information on how to enable AUM, see the Oracle Database Administrator's Guide, "Managing Undo Space."
To enable Automatic Undo Management (AUM)
- Create the
undo tablespace
by running the following command:CREATE UNDO TABLESPACE tablespace_name DATAFILE 'datafile name' SIZE 32M REUSE AUTOEXTEND ON EXTENT MANAGEMENT LOCAL
- Set the following
init.ora
parameters:- undo_management = AUTO
- undo_tablespace = tablespace_name
- undo_retention = 900
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The following table shows the default extents sizes.
Table 64 Default extents sizes
Tablespace | Size |
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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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