What is contained in the Subsystem Analyzer FMT_WIO column?

Products

• Subsystem Analyzer for DB2 for z/OS

Issue/Introduction

What is contained in the Subsystem Analyzer for Db2 for z/OS (PSA) FMT_WIO column.

Resolution

This column contains a count of the DB2 pre-formatting I/O's of new pages in a table space during execution time.
A common reason would be Inserts which cause new extents to be built and new pages to be formatted by Db2. 

If the PREFORMAT option is used in a LOAD or REORG utility, depending upon the size of the object, this could generate a substantial
amount of "Format Write I/O's".