Matching Log I/O Size for Log Caches

If you create a cache for the transaction log of a database, configure most of the space in that cache to match the log I/O size.

The default value is twice the server’s logical page size (for a server with 2K logical page size, it is 4K, for a server with 4K logical page size, it is 8K, and so on). SAP ASE uses 2K I/O for the log if a 4K pool is not available. Use sp_logiosize to change the log I/O size. The log I/O size of each database is reported in the error log when SAP ASE starts, or you can issue sp_logiosize with no parameters to check the size of a database.

This example creates a 4K pool in the pubs_log cache:

sp_poolconfig pubs_log, "3M", "4K"

You can also create a 4K memory pool in the default data cache for use by transaction logs of any databases that are not bound to another cache:

sp_poolconfig "default data cache", "2.5M", "4K"

See Performance and Tuning Series: Basics > Choosing the I/O size for the transaction log.