Fragmentation guidelines
One of the most frequent causes of poor performance in relational database systems is contention for data that resides on a single I/O device. Proper fragmentation of high-use tables can significantly reduce I/O contention. These topics discuss the performance considerations that are involved when you use table fragmentation.
The database server supports table fragmentation (also partitioning), which allows you to store data from a single table on multiple disk devices. Fragmentation enables you to define groups of rows or index keys within a table according to some algorithm or scheme. You can store each group or fragment (also referred to as a partition) in a separate dbspace associated with a specific physical disk.
For information about fragmentation and parallel execution, see Parallel database query (PDQ).
For an introduction to fragmentation concepts and methods, see the IBM Informix Database Design and Implementation Guide. For information about the SQL statements that manage fragments, see the IBM Informix Guide to SQL: Syntax.