Skip to main content

Documentation Index

Fetch the complete documentation index at: https://docs.activeviam.com/llms.txt

Use this file to discover all available pages before exploring further.

This page explains how to configure Atoti What-If for distributed deployments where data is spread across multiple nodes.

​
What is distributed mode

In a distributed Atoti Server deployment, data is partitioned across multiple data nodes, with a query node coordinating requests. Atoti What-If supports this architecture by sending simulation operations to all data nodes via REST calls. When distributed mode is enabled, the starter creates a RestDistributedDatabaseService that:
  • Discovers data node addresses from the distributed pivot
  • Forwards database operations to all nodes
  • Merges query results from multiple nodes
  • Handles authentication using JWT tokens

​
Prerequisites

Before enabling distributed mode:
  • Your Atoti Server application must be configured for distribution
  • A query node with IMultiVersionDistributedActivePivot must be available
  • JWT authentication must be configured
  • Data nodes must expose the Database Service REST API

​
How to enable distributed mode

Add the following properties to your application.yml: 
atoti:
  what-if:
    distribution:
      enabled: true
      query-node-name: "MyQueryNode"
The query-node-name must match the name of your query node pivot as configured in your Atoti Server application.

​
Auto-configured beans

When distribution.enabled: true, the starter creates:
BeanDescription
IDistributedQueryResultsMergerMerges results from multiple data nodes
AddressSupplierSupplies data node addresses from the distributed pivot
AuthenticatorSupplierSupplies JWT authenticators for REST calls
RestDistributedDatabaseServiceThe distributed database service (marked as @Primary)

​
Configuration properties

PropertyTypeDefaultDescription
atoti.what-if.distribution.enabledbooleanfalseEnables distributed mode
atoti.what-if.distribution.query-node-nameString""Name of the query node pivot
atoti.what-if.distribution.create-distributed-servicebooleantrueWhether to auto-create RestDistributedDatabaseService

​
How to provide a custom address supplier

By default, the starter discovers data node addresses from the distributed pivot. To use a custom address supplier: 
@Bean
public AddressSupplier customAddressSupplier() {
    return () -> Set.of(
        "http://data-node-1:8080/",
        "http://data-node-2:8080/",
        "http://data-node-3:8080/"
    );
}

​
How to provide a custom authenticator

By default, JWT authentication is used. To provide a custom authenticator: 
@Bean
public AuthenticatorSupplier customAuthenticatorSupplier() {
    return () -> new MyCustomAuthenticator();
}

​
How to provide a custom distributed database service

To replace the auto-configured RestDistributedDatabaseService:
  1. Set create-distributed-service: false in your configuration:
atoti:
  what-if:
    distribution:
      enabled: true
      query-node-name: "MyQueryNode"
      create-distributed-service: false
  1. Define your custom bean:
@Bean
@Primary
public IDatabaseService customDistributedDatabaseService(
        IDistributedQueryResultsMerger resultsMerger,
        AddressSupplier addressSupplier,
        AuthenticatorSupplier authenticatorSupplier) {
    return new MyCustomDistributedDatabaseService(
            resultsMerger, addressSupplier, authenticatorSupplier);
}

​
How to customize result merging

The DefaultDistributedQueryResultsMerger combines query results from all data nodes. To customize merging logic: 
@Bean
public IDistributedQueryResultsMerger customResultsMerger() {
    return new IDistributedQueryResultsMerger() {
        @Override
        public JsonDatabaseQueryResult mergeQueryResults(
                List<JsonDatabaseQueryResult> results) {
            // Custom merge logic
        }
        // Implement other methods as needed
    };
}

​
Error handling

The RestDistributedDatabaseService throws:
  • ActiveViamRuntimeException if no data node addresses are available
  • InternalServiceException if operations on distributed nodes fail
Ensure your error handling accounts for partial failures when some nodes are unreachable.