Accelerated query tables

Accelerated query tables, or AQTs, store information about data marts that the database server uses to determine which queries can be processed by Informix® Warehouse Accelerator.

The information about AQTs that is stored in the catalog tables of the database server is the same information that is stored in the catalog tables for other types of views.

There can be many AQTs. If the first AQT is not able to satisfy a query, the database server continues to search for a match until the query is checked against all of the AQTs. If a match is found, the query is sent to Informix Warehouse Accelerator for processing. If no match is found, the query is processed by the database server.

A single AQT can have a maximum of 255 tables and 750 columns.

To be sent to Informix Warehouse Accelerator, the query must meet the following criteria:

• The query must refer to a subset of the tables in the AQT.
• The table references, or joins, specified in the query must be the same as the references in the data mart definition.
• The query must include only one fact table.
• The query must have an INNER JOIN or LEFT JOIN with the fact table on the left dominant side.
• The scalar and aggregate functions in the query must be supported by Informix Warehouse Accelerator.

A data mart can be in one of several different states, but the associated AQTs are either active or inactive.

When you drop a data mart from an accelerator, the associated AQTs are removed automatically from the database server.

You can use the onstat -g aqt command to view information about the data marts and the associated AQTs.