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Version: 3.8

Requirements and Recommendations for the Underlying Databases of ScalarDB

This document explains the requirements and recommendations in the underlying databases of ScalarDB to make ScalarDB applications work correctly and efficiently.


ScalarDB requires each underlying database to provide certain capabilities to run transactions and analytics on the databases. This document explains the general requirements and how to configure each database to achieve the requirements.

General requirements


ScalarDB requires each underlying database to provide at least the following capabilities to run transactions on the databases:

  • Linearizable read and conditional mutations (write and delete) on a single database record.
  • Durability of written database records.
  • Ability to store arbitrary data besides application data in each database record.


ScalarDB requires each underlying database to provide the following capability to run analytics on the databases:

  • Ability to return only committed records.

You need to have database accounts that have enough privileges to access the databases through ScalarDB since ScalarDB runs on the underlying databases not only for CRUD operations but also for performing operations like creating or altering schemas, tables, or indexes. ScalarDB basically requires a fully privileged account to access the underlying databases.

How to configure databases to achieve the general requirements

Select your database for details on how to configure it to achieve the general requirements.


  • Use a single primary server or synchronized multi-primary servers for all operations (no read operations on read replicas that are asynchronously replicated from a primary database).
  • Use read-committed or stricter isolation levels.


  • Use read-committed or stricter isolation levels.


Properly configuring each underlying database of ScalarDB for high performance and high availability is recommended. The following recommendations include some knobs and configurations to update.


ScalarDB can be seen as an application of underlying databases, so you may want to try updating other knobs and configurations that are commonly used to improve efficiency.

  • Use read-committed isolation for better performance.
  • Follow the performance optimization best practices for each database. For example, increasing the buffer size (for example, shared_buffers in PostgreSQL) and increasing the number of connections (for example, max_connections in PostgreSQL) are usually recommended for better performance.