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Data warehousing
In addition to designing and implementing Informix® dimensional databases, you can use tools to create data warehouse applications and optimize your data warehouse queries.
Informix® Warehouse Accelerator
The Informix® Warehouse Accelerator Administration Guide includes information about installing and configuring the accelerator server, creating data marts, accelerators, and accelerated query tables (AQTs).
Configuration
You must configure the accelerator server to work with the Informix® database server.
The ondwa utility
Use the ondwa utility to set up and work with the accelerator server.
ondwa start command
The ondwa start command starts all of the accelerator server nodes. If the accelerator server is installed on a cluster hardware system, and if some of the cluster nodes are stopped, the ondwa start command starts the offline cluster nodes.

Data warehousing
In addition to designing and implementing Informix® dimensional databases, you can use tools to create data warehouse applications and optimize your data warehouse queries.
- Dimensional databases
  The Informix® Data Warehouse Guide provides information to help you design, implement, and manage dimensional databases, and describes the tools that you can use to create data warehouses and optimize your data warehouse queries.
- Informix® Warehouse Accelerator
  The Informix® Warehouse Accelerator Administration Guide includes information about installing and configuring the accelerator server, creating data marts, accelerators, and accelerated query tables (AQTs).
  - Overview of Informix® Warehouse Accelerator
    Informix® Warehouse Accelerator is a product that you use to improve the performance of your warehouse queries.
  - Installation
    You can install Informix® Warehouse Accelerator on the same computer as the Informix database server, on a separate computer, or on a cluster (including a high-availability cluster).
  - Configuration
    You must configure the accelerator server to work with the Informix® database server.
    - Configuring Informix® Warehouse Accelerator
      You must configure the Informix® Warehouse Accelerator before you can enable query acceleration and set up the connection between the accelerator server and the database server.
    - Configuring Informix® Warehouse Accelerator for hardware clusters
      You must configure Informix® Warehouse Accelerator before you can enable query acceleration and set up the connection between the accelerator server and the database server. In a cluster system, one accelerator server coordinator node uses the first cluster node, and then each cluster node that you add to the cluster becomes an accelerator server worker node.
    - Configuring Informix® Warehouse Accelerator on secondary servers in a high-availability environment
      You can create data marts, load data mart data, and accelerate queries on one or more secondary servers in a high-availability cluster. By using secondary servers for Informix® Warehouse Accelerator, you have greater flexibility in a mixed-workload environment. For example, you can dedicate the primary server for OLTP transactions and use a secondary server for processing the warehouse analytic queries. Configure the secondary servers by modifying the ONCONFIG file of each secondary server, connecting one of the secondary servers to an accelerator, and copying the sqlhosts entry in the sqlhosts file to each server in the cluster.
    - dwainst.conf configuration file
      The dwainst.conf configuration file contains the parameters that are used to configure the accelerator server.
    - Configuring memory for Informix® Warehouse Accelerator
      To process queries efficiently, verify that you have the optimal configuration for the operating-system kernel parameters, shared memory, and swap space on the computer where Informix® Warehouse Accelerator is installed. You can also monitor the virtual memory usage to see if you need to reduce the total size of the loaded data marts or add physical memory.
    - The ondwa utility
      Use the ondwa utility to set up and work with the accelerator server.
      - Users who can run the ondwa commands
        Either user root or user informix can run the ondwa commands. To run the ondwa commands as user informix requires setup steps. It is recommended that you determine which user will run the ondwa commands and to use the same user consistently. Whether you run the ondwa commands as user root or as user informix, user informix must be defined on the accelerator server. Otherwise, the ondwa commands will fail.
      - ondwa setup command
        The ondwa setup command creates the files and subdirectories that are required to run an accelerator server.
      - ondwa start command
        The ondwa start command starts all of the accelerator server nodes. If the accelerator server is installed on a cluster hardware system, and if some of the cluster nodes are stopped, the ondwa start command starts the offline cluster nodes.
      - ondwa status command
        The ondwa status command shows information about the status of the accelerator server nodes, the cluster status, and the expected node count.
      - ondwa listmarts command
        Use the ondwa listmarts command to show information about existing data marts in the accelerators.
      - ondwa getpin command
        Use the ondwa getpin command to retrieve the IP address, port number, and pairing code that connect a database server to an accelerator server.
      - ondwa tasks command
        The ondwa tasks command shows information about the tasks that are currently running, memory that is used, and resources.
      - ondwa stop command
        The ondwa stop command stops the accelerator server.
      - ondwa reset command
        The ondwa reset command removes all of the files from the accelerator server storage directory that were created by the accelerator server under the shared and local/* subdirectories.
      - ondwa clean command
        The ondwa clean command cleans the accelerator server directory.
  - Create an accelerator
    You create an accelerator by connecting the Informix® database server to the accelerator server.
  - Data marts and AQTs
    For efficient query processing, the accelerator server must have its own copy of the data. The data is stored in logical collections of related data, or data marts. A data mart specifies the collection of tables that are loaded into an accelerator and the relationships, or references, between these tables.
  - Turning on query acceleration
    Before queries can be routed to the accelerator server for processing, you must set the use_dwa session environment variable.
  - SQL administration routines
    You can use the Informix® Warehouse Accelerator functions and procedures from the command line or in an application to automate administration tasks.
  - Reversion requirements for Informix Warehouse Accelerator
  - Troubleshooting
  - Sample warehouse schema
    The Informix® Warehouse Accelerator examples use this sample warehouse schema.
  - Sysmaster interface (SMI) pseudo tables for query probing data
    The SMI tables provide a way to access probing data in a relational form, which is most convenient for further processing.

ondwa start command

The ondwa start command starts all of the accelerator server nodes. If the accelerator server is installed on a cluster hardware system, and if some of the cluster nodes are stopped, the ondwa start command starts the offline cluster nodes.

To run this command, log on to the computer where the accelerator server is installed either as user root or as user informix. For you to run the command as user informix, specific memory resources must be available. For more information, see Users who can run the ondwa commands.

Usage:

$ ondwa start

The output of a accelerator server node is recorded in the log file for the node, for example: node0.log, node1.log, and so forth. These files are located in the accelerator server storage directory. After the ondwa start command has finished, your accelerator server is ready to use.

After you run ondwa start, you should run the ondwa status command to check that status of the accelerator server.