|Oracle® Database Reference
10g Release 1 (10.1)
Part Number B10755-01
|Range of values|
DB_BLOCK_CHECKSUM determines whether DBWn and the direct loader will calculate a checksum (a number calculated from all the bytes stored in the block) and store it in the cache header of every data block when writing it to disk. Checksums are verified when a block is read-only if this parameter is
true and the last write of the block stored a checksum. In addition, Oracle gives every log block a checksum before writing it to the current log.
If this parameter is set to
false, DBWn calculates checksums only for the
SYSTEM tablespace, but not for user tablespaces.
Checksums allow Oracle to detect corruption caused by underlying disks, storage systems, or I/O systems. Turning on this feature typically causes only an additional 1% to 2% overhead. Therefore, Oracle recommends that you set