DbSchema Database Designer

DbSchema | Firebird - How to Set up Database Clustering?

Publish on DbSchema Blog >>>

Firebird - How to Set up Database Clustering in isql and DbSchema

Firebird alt >

Table of Contents


In today’s data-driven world, database management has become more complex and essential. One technique that has gained popularity in recent years is Database Clustering. Specifically, this article will focus on setting up database clustering using Firebird, isql, and DbSchema.


Before we begin, ensure you have the following:

  • Firebird installed and set up on your system
  • Understanding of isql and DbSchema
  • Basic SQL knowledge

For installation and establishing connection you can read our article Firebird-How to create a database?

What is Database Clustering?

Database Clustering is a method of storing database data on several machines (nodes), thereby enhancing the performance, availability, and scalability of the system.

Purpose of Using Database Clustering

Database Clustering serves multiple purposes:

  • It enhances the availability of your database, ensuring that it remains functional even if one or more nodes fail.
  • It improves the scalability, allowing you to add more nodes as your database grows.

Permissions and Restrictions for Database Clustering

To use database clustering, one needs to have admin rights on all servers that will be part of the cluster. The servers should have synchronized clocks, a stable network connection, and each server’s disk space should be similar.

Advantages and Limitations of Database Clustering


  • High availability
  • Scalability
  • Improved performance


  • Overhead costs for setting up and maintaining the cluster
  • Potential data inconsistency issues

How Firebird Handles Clustering

Firebird doesn’t inherently support database clustering. However, one can achieve this by employing third-party tools like DbSchema and utilizing its features such as Replication and Sharding.

Setting up Database Clustering in isql

Firebird does not inherently support database clustering, and setting up database clustering via isql is not standard practice as it requires manual handling of data synchronization. This means that you would have to manually manage data replication across each node in your cluster.

Here’s a more detailed guide on how you could potentially approach this:

  1. Install Firebird: Download and install Firebird on all servers that will be part of the cluster.

  2. Set up your databases: Using isql, create an identical database structure on each node that will be part of the cluster. This can be done using the CREATE DATABASE command.

    __ CREATE DATABASE 'localhost:/path/to/database.fdb' USER 'sysdba' PASSWORD 'masterkey'; __

  3. Create Tables: Create tables in each database with the same structure. Here’s an example of creating a users table:

    __ CREATE TABLE users ( id INTEGER NOT NULL PRIMARY KEY, name VARCHAR(50), email VARCHAR(100) ); __

  4. Establish replication triggers: For each table that needs to be part of the cluster, establish AFTER INSERT, AFTER UPDATE, and AFTER DELETE triggers. These triggers should manage the replication of data to the other nodes.

    Here is an example of a trigger that would replicate INSERT operations from one node to another:

    SET TERM ^ ;

    CREATE TRIGGER users_ai FOR users
    INSERT INTO “localhost:/path/to/other/database.fdb”.users
    (id, name, email)
    (NEW.id, NEW.name, NEW.email);

    SET TERM ; ^

This code snippet is defining a trigger in Firebird’s isql. When a new row is inserted into the users table (AFTER INSERT), the trigger ‘users_ai’ becomes active and inserts the same row into a users table on a different database (“localhost:/path/to/other/database.fdb”.users). The SET TERM commands are used to define the delimiter for the trigger definition; ^ is used as the delimiter here instead of the default ;

Similar triggers should be created for UPDATE and DELETE operations, ensuring that any changes made to data on one node are mirrored on the other nodes.

  1. Test the system: After setting up the databases and replication triggers, test the system to ensure that data is accurately synchronized between the nodes. You can do this by inserting some data into one of your nodes and checking if it gets replicated across the other nodes.

Remember, this method would require manually handling potential issues such as collision detection and conflict resolution. Also, the performance may vary based on network latency and the database’s overall size.

Moreover, setting up database clustering manually with isql is complex and can easily lead to data inconsistencies if not done carefully. For production systems, it’s advisable to use a database system that inherently supports clustering or use a third-party tool that provides such capabilities, like DbSchema, as previously explained.

Setting up Database Clustering in DbSchema

While Firebird does not natively support database clustering, you can achieve similar functionality using third-party tools like DbSchema. Here’s how:

  1. Install DbSchema: Download and install DbSchema on your primary machine. You can download it from the official DbSchema website.

  2. Connect DbSchema to Firebird: After installing DbSchema, connect it to your Firebird database. You can do this by creating a new connection in DbSchema and entering the necessary Firebird connection details.

  3. Create a Replication Set: DbSchema provides a ‘Replication Set’ feature that allows you to easily manage data replication between different servers. To create a new replication set, navigate to the Replication Sets option in DbSchema and click on New. Then, add the tables that you want to replicate.

  4. Add Nodes: The next step is to add the nodes (servers) that you want to be part of the cluster. To do this, go to the Nodes section in DbSchema and add each server’s connection details.

  5. Start Replication: After setting up the Replication Set and adding the nodes, you can start the replication process. DbSchema will handle the replication of data between the different servers.

  6. Monitor the Replication Process: DbSchema provides monitoring tools to help you keep track of the replication process. You can access these tools from the Replication Sets section in DbSchema.

Visually Manage Firebird using DbSchema

DbSchema is a Firebird client and visual designer. DbSchema has a free Community Edition, which can be downloaded here.

Key Features of DbSchema:

Following are the key features of DbSchema which distinguish it from other database GUI tools.


Setting up database clustering with Firebird, isql, and DbSchema may seem daunting initially, but once set up, it can provide substantial benefits in terms of availability, scalability, and performance. However, the overhead costs and potential data inconsistency issues need to be accounted for.


  1. Firebird Documentation: FirebirdSQL.org
  2. DbSchema Documentation: DbSchema.com

Visually Manage Databases using DbSchema

DbSchema is a databases client and visual designer. DbSchema has a free Community Edition, which can be downloaded here.
DbSchema main features include:

DbSchema Designer alt >

Interactive Diagrams

Design tables, column and foreign keys directly in diagrams, by double-clicking them. Changes will be saved to the design model and, if DbSchema is connected to the database also into the database. More.

Connection Dialog alt >

Simple Connection Dialog

Choose the database location, the user and password, and simply get connected. Choose 'Edit Manually' into the JDBC URL combo to enter a custom URL. More.

Relational Data Explorer alt >

Relational Data Explorer

Explore data from multiple tables simultaneously, using foreign keys or virtual foreign keys. Double-click cells to edit the data. More.

Query Builder alt >

Query Builder

Create SQL Queries featuring JOINS, GROUP BY, ORDER BY just using the mouse. More.

SQL Query Editor alt >

SQL Query Editor

Edit and execute SQL Queries. The editor is autocompletion-enabled. More.

Schema Synchronization alt >

Design Schema in Team & Schema Deployment

DbSchema is using the design model, a copy of the schema structure, independent of the database.
The design model can be saved to file and shared in a team.
Connecting to another database you may compare the design model with the database, commit the differences or merge them in the design model. More.

Dark Theme alt >

Dark Theme

Configurable styles & dark theme. More.

Many features are available in the free Community edition.
The Pro edition adds capabilities to save the design to the model file, design schema in team and deploy the schema on multiple databases.

DbSchema can be downloaded for free. No registration is required.