PHYSBUFF

onconfig.std value

32

units

Kilobytes

range of values

4 kilobytes through (32767 * page size / 1024) kilobytes.

takes effect

When the database server is shut down and restarted

utilities

onstat -l buffer field, first section (For m ore information, see page onstat -l.)

refer to

Physical-log buffer, in the shared-memory chapter of the IBM Informix Administrator's Guide

PHYSBUFF specifies the size in kilobytes of the two physical-log buffers in shared memory. Double buffering permits user threads to write to the active physical-log buffer while the other buffer is being flushed to the physical log on disk. The value of the PHYSBUFF parameter determines how frequently the database server needs to flush the physical-log buffer to the physical-log file. The recommended value for PHYSBUFF is 32 pages.

A write to the physical-log buffer is exactly one page in length. Choose a value for PHYSBUFF that is evenly divisible by the page size. If the value of PHYSBUFF is not evenly divisible by the page size, the database server rounds down the size to the nearest value that is evenly divisible by the page size.

The user-data portion of a smart large object does not pass through the physical-log buffers.

The system page size is platform-dependent on Dynamic Server. To obtain the system page size, use the commands listed in the table in System Page Size.