Creating index specifications
For relational data sources, create index specifications
to store information about the columns of remote indexes in the global
catalog and to ensure optimal performance of search queries.
Index specifications in a federated system
In a federated system, you use the CREATE INDEX statement with a nickname to store information in the global catalog about the availability of an index on the remote object. The query optimizer uses this information to optimize queries.
Creating index specifications for data source objects
When a nickname is created for a data source table, the federated server supplies the global catalog with information about any indexes that the data source table has. The optimizer uses this information to expedite the processing of distributed requests. This information is a set of metadata and is called an index specification .
Creating index specifications on tables that acquire new indexes
For situations in which a table acquires a new index, you should create an index specification on the nickname that corresponds to the table.
Creating index specifications on views
When a nickname is created for a view, the federated server is unaware of the underlying table (and its indexes) from which the view was generated. Create an index specification for the view so that the SQL Compiler can use this information when processing queries that reference the view.
Creating index specifications on Informix synonyms
This topic describes the action that the federated server takes for Informix synonyms based on a table or on a view: