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Detached Indexes
Figure 5-11
Storage Scheme for the Indexes Attached to a Fragmented
Table for Dynamic Server with AD and XP Options
Coserver 1
Dbspace 1
Data
Coserver 2
Dbspace 2
Index
Data
Index
...
Coserver n
...
Dbspace n
...
Data
Index
♦
Detached Indexes
The fragmentation scheme for an index can differ from that of table data. A
detached index is an index that has a fragmentation strategy independent of
the table fragmentation. You can use the FRAGMENT BY clause of the CREATE
INDEX statement to fragment the index for any table.
With Dynamic Server, you can use the expression-based distribution scheme
to create a detached index for any table. However, you cannot use the roundrobin distribution scheme for an index.
IDS
You can change the fragmentation strategy of a fragmented index with the
ALTER FRAGMENT ON INDEX statement. ♦
AD/XP
5-40
With Dynamic Server with AD and XP Options, you can use an expression,
system-defined hash, or hybrid distribution scheme to create detached
indexes for any table. However, you cannot use the round-robin distribution
scheme for an index.
Informix Guide to Database Design and Implementation