Knowledge Discovery 26.3.0
26.3 Release Notes

# Distributed Action Handler

Distributed Action Handler is an ACI server. For details of changes that affect all ACI servers, see ACI Server Framework.

## 26.3.0

### New Features

- The `TermGetBest` action now supports the `UseVectors` parameter.

### Resolved Issues

- When sending the `Suggest` action to the DAH, the `UseVectors` parameter was not respected.

  NOTE: This change requires you to update all child Content component engines to version 26.3 or later.

## 26.2.0

### New Features

- The `EngineManagement` action now supports the `SSLConfig` parameter when `EngineAction` is set to `EngineAdd`, to allow you to dynamically set SSL configuration details for the new server.

### Resolved Issues

- The DAH response for the `GetQueryTagValues` action could miss `end_date`, `end_date_with_offset`, and `type` attributes that were present in the Content component response for the same action.

- The DAH response for the `GetQueryTagValues` action could omit a numeric or date range that contained no documents when `DocumentCount` was set, when the Content component would print the range with a tag of count=0. DAH is now consistent with Content.

- In certain situations DAH could overcount the number of values returned by a `GetQueryTagValues` action when `FieldDependenceMultiLevel` was set. This issue occurred when one child server returned zero documents in a range and another contained documents in that range with N subvalues in the subsequent `FieldDependenceMultiLevel` field, and DAH would count N+1 subvalues in total.

## 26.1.0

### New Features

There were no new features in this release.

### Resolved Issues

- When a `GetQueryTagValues` action was sent with `FieldDependenceMultiLevel` set to True, and which contained only one `FieldName` field that returned results, and also contained a `Ranges` parameter that contained only one range for that field, then DAH could exit unexpectedly.

- The `ValuePercentiles` action parameter was being ignored in the `GetQueryTagValues` action.

## 25.4.0

There were no new features or resolved issues in this release.

## 25.3.0

There were no new features or resolved issues in this release.

## 25.2.0

### New Features

- DAH can now read an AES key for security info encryption directly from a configuration setting. You can now set the `SecurityInfoKeys` configuration parameter to a verbatim AES key. Previously, it was only possible to set a list of TEA encryption keys, or the path of an AES key file on disk.

  This feature enables you to import a key directly from a secret source, such as an environment variable or HashiCorp® Vault. The key protects user security info tokens, which in turn allow access to secure documents, so OpenText recommends that you do not supply it as a plain text configuration value. Setting a plain text value returns a configuration validation error, but does not prevent the server from starting up.

### Resolved Issues

- DAH did not correctly handle the case where a configuration parameter had a single value to apply to multiple engine mirrors. This issue applied to DAH versions 24.4.0 and 25.1.0, for the parameters `Weight`, `Priority`, and `SSLConfig` for child server configuration. In this case, a single value was treated as non-valid, and DAH required an individual value for each mirror. The correct behavior has been restored in version 25.2.0.

- DAH could return an error incorrectly from a `GetQueryTagValues` action where `FieldDependence` and `FieldDependenceMultiLevel` were both set to True and the child engines did not return any values, for example, if a `FieldText` query was set to match a nonexistent value.

- When DAH received a malformed XML response from a child engine, it could spuriously log that it `could not connect`, and mark that child engine as down.

- Sending a `GetContent` action to DAH with the `StateID` parameter could fail to return all the requested documents if multiple tokens were specified, or if some documents had already been deleted, and could sometimes cause an interruption of service, depending on the distribution of documents across child engines.

## 25.1.0

There were no new features or resolved issues in this release.

## 24.4.0

There were no new features or resolved issues in this release.

## 24.3.0

There were no new features or resolved issues in this release.

## 24.2.0

### New Features

There were no new features in this release.

### Resolved Issues

- DAH did not correctly handle vector parameters that were added to the Content component (`Summary=vector` and `VectorMetadata`).

## 24.1.0

There were no new features or resolved issues in this release.

## 23.4.0

### New Features

- When you use the `Suggest` action, DAH now uses information from structured fields to suggest relevant documents, as well as unstructured data. This option requires your Content components to have field statistics enabled.

- DAH did not apply proxied command timeouts. It now uses the `EngineTimeout` parameter as a TCP socket read timeout.

### Resolved Issues

There were no resolved issues in this release.

## 23.3.0

There were no new features or resolved issues in this release.

## 23.2.0

There were no new features or resolved issues in this release.

### Notes

- In IDOL 12.13 and earlier, the `ACIEncryption` child server configuration parameter had a default value of True. This parameter now has a default value of False, to reflect that ACI encryption has been deprecated since IDOL 12.6.0.

  If you have the `ACIEncryption` parameter set to False in your configuration file, you can remove it.

  If you do not have the `ACIEncryption` parameter in your configuration file, and you are using the deprecated ACI encryption methods, you can set it manually to True. However, OpenText strongly recommends that you update your configuration to use the more secure TLS/SSL methods for secure communications.

  Documentation for the `ACIEncryption` parameter has been removed, along with documentation for the following ACI encryption-related parameters:

  - `[Server] ForwardEncryptedRequests`

  - `[MyChildServer] Krb5Realm`

  - `[MyChildServer] Krb5Service`

## Deprecated Features

The following features are deprecated and might be removed in a future release.

Category | Deprecated Feature | Deprecated Since
--- | --- | ---
Federated Search | Configuration and action parameters for federating queries with k2, Ultraseek, and Z39.50 servers. | 24.4.0

Copyright 2026 Open Text
Version 26.3.0 | Last updated July 2026

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Product: Knowledge Discovery 26.3.0

Topic Title: Distributed Action Handler