The database server stores index pages into different
tblspaces than the table with which it is associated. Within the extent,
individual index pages contain different types of data. Index pages
can be separated into the following categories:
Index pages (root, branch, and leaf pages)
Index pages contain
the index information for the table.
Bitmap pages
Bitmap pages contain control information that
monitors the fullness of every page in the extent.
Free pages
Free pages are pages in the extent that are allocated
for tblspace use, but whose function has not yet been defined. Free
pages can be used to store any kind of information: data, index, TEXT
or BYTE data, or bitmap.
All indexes are detached unless you explicitly specify
attached indexes.
Important: An extent that is allocated
for a table fragment does not contain index pages. Index pages for
a fragmented table always reside in a separate tblspace. For more
information, see fragmenting table indexes in the chapter on table
fragmentation and PDQ in the Informix® Administrator's
Guide.
Extent Structure of an Index illustrates
the extent structure of an index. Figure 1: Extent Structure of an Index
