For OLTP transactions and some DSS queries, you might improve performance by encouraging local lookups if each coserver contains a copy of a frequently accessed table.
The following kinds of tables are candidates for duplication:
Only relatively small tables should be duplicated. The primary reason to have a table duplicate on each coserver is so that a transaction executed from that coserver can read the table into memory for repeated accesses.
Duplicated tables cannot be updated. If you need to update a duplicated table, you must drop all duplicates. After the table is updated, you can duplicate it again.
Tables that already contain fragments on other coservers cannot be duplicated.
For detailed information about the CREATE DUPLICATE OF TABLE and DROP DUPLICATE OF TABLE, statements, see the IBM Informix: Guide to SQL Syntax.
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