Databases Reference
In-Depth Information
LGWR
writes online redo logs sequentially, using a RAID 5 on the
disks, where online redo logs are stored. This can lead to poor
performance due to the slower write times that characterize this
type of disk array—using RAID 0+1 is preferable.
See also
F
The
Choosing different RAID levels for different Oracle files
recipe in this chapter
Striping objects across multiple disks
In the previous recipe, we have seen how to distribute Oracle files on different disks to
obtain better performance. In this recipe, we will see how to stripe objects using different
tablespaces or data files, to improve performance.
How to do it...
The following steps will demonstrate how to stripe objects across multiple disks:
1.
Connect to the database as
SYSDBA
:
CONNECT / AS SYSDBA
2.
Create a new tablespace,
EXAMPLE2
, on a different disk:
CREATE TABLESPACE EXAMPLE2
DATAFILE '/u01/oradata/TESTDB2/example2.dbf' SIZE 100M;
3.
Move the
CUSTOMERS
table of the
SH
schema to the newly-created tablespace:
ALTER TABLE SH.CUSTOMERS MOVE TABLESPACE EXAMPLE2 NOLOGGING;
4.
Identify the indexes that need to be rebuilt:
SELECT INDEX_NAME, STATUS FROM ALL_INDEXES
WHERE TABLE_OWNER = 'SH' AND TABLE_NAME = 'CUSTOMERS';
5.
Rebuild the indexes:
ALTER INDEX SH.CUSTOMERS_PK REBUILD;
ALTER INDEX SH.CUSTOMERS_GENDER_BIX REBUILD;
ALTER INDEX SH.CUSTOMERS_MARITAL_BIX REBUILD;
ALTER INDEX SH.CUSTOMERS_YOB_BIX REBUILD;
