Initialization Parameters, 29 of 188

DB_BLOCK_CHECKING

Parameter type:	Boolean
Parameter class:	Dynamic. Scope = `ALTER SESSION`, `ALTER SYSTEM ... DEFERRED.`
Default value:	`FALSE`
Range of values:	`TRUE` \| `FALSE`
`DB_BLOCK_CHECKING` controls whether Oracle performs block checking for data blocks. When this parameter is set to `TRUE`, Oracle performs block checking for all data blocks. When it is set to `FALSE`, Oracle does not perform block checking for blocks in the user tablespaces. However, block checking for the `SYSTEM` tablespace is always turned on. Oracle checks a block by walking through the data on the block, making sure it is self-consistent. Block checking can often prevent memory and data corruption. Block checking typically causes 1% to 10% overhead, depending on workload. The more updates or inserts in a workload, the more expensive it is to turn on block checking. Oracle recommends that you set `DB_BLOCK_CHECKING` to `TRUE` if the performance overhead is acceptable.