Oracle "Check Logical" parameter - 4X times faster if not active!

[David_McMullin]

I moved an oracle database from network to Fiber channel and saw no speed improvement, and after many painful days of tuning, the DBA removed the "Check Logical" parameter.
My 7 hour backup completed in 1.5 hours! 4.6X faster.

My larger databases actually started to overrun the disk arrays. Nice when backups run too fast and you have to slow them up!

Thought I would throw this info out there, if you are not getting 50+ MB/Sec throughput per child job...

[Will_Restore]

CHECK LOGICAL

Tests data and index blocks that pass physical corruption checks for logical corruption, for example, corruption of a row piece or index entry. If RMAN finds logical corruption, it logs the block in the alert.log and server session trace file. If the total number of physical and logical corruptions detected in a file is less than its MAXCORRUPT setting, the RMAN command completes and the database populates the V$DATABASE_BLOCK_CORRUPTION view with corrupt block ranges. If MAXCORRUPT is exceeded, the command terminates without populating the views. If the initialization parameter DB_BLOCK_CHECKSUM=TRUE, and if MAXCORRUPT and NOCHECKSUM are not set, then specifying CHECK LOGICAL detects all types of corruption that are possible to detect.

Sounds good but is the DBA checking those views to verify no corruption? 

[David_McMullin · Accepted solution]

It always checks for physical corruption, this is a logical check.

I guess we can put out a caveat, to have DBA check the logical blocks