Distributed Action Handler 26.1
Distributed Action Handler Help

# About the Distributed Action Handler

OpenText Distributed Action Handler (DAH) is a server that distributes ACI actions to Knowledge Discovery components. Distribution enables you to scale your system in a linear manner, increasing the speed at which it runs actions and saving processing time. Having multiple components also ensures uninterrupted service if a component fails.

The setup of your child components is independent of the DAH, because they are architecturally unaware of it.

You can run the DAH in the following modes:

- Mirror mode. The child servers (the servers that the DAH distributes actions to) are identical—that is, each one is configured the same way and contains the same data as the others.

- Non-mirror mode. The child servers are all different—that is, each one is configured differently and contains different data from the others. If you run the DAH in non-mirror mode, you must set up virtual databases (VDBs) of the following types:

  - Combinator VDB. The virtual database forwards an action to all the databases that it represents. The VDB collates and sorts the results before it returns them.

  - Distributor VDB. The virtual database forwards an action to one of the databases that it represents. These databases must be identical (that is, all the databases are exact copies of each other and contain the same data). The distribution method determines which database the distributor VDB forwards actions to.

NOTE: Virtual databases can map to Content component databases or to other virtual databases that you set up for the DAH.

However, in general, OpenText recommends that combinator virtual databases map only to other virtual databases (combinator VDBs combine results from distributor VDBs). Distributor databases normally map directly to the Content component databases. OpenText recommends that you do not use them to distribute queries to combinator VDBs.

Copyright 2025 Open Text
Version 26.1 | Last updated January 2026

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Product: Knowledge Discovery Distributed Action Handler 26.1

Topic Title: About the Distributed Action Handler