Choosing the right database is a critical choice when building any software application. All databases have different strengths and weaknesses when it comes to performance, so deciding which database has the most benefits and the most minor downsides for your specific use case and data model is an important decision. Below you will find an overview of the key concepts, architecture, features, use cases, and pricing models of Redis and OpenTSDB so you can quickly see how they compare against each other.

The primary purpose of this article is to compare how Redis and OpenTSDB perform for workloads involving time series data, not for all possible use cases. Time series data typically presents a unique challenge in terms of database performance. This is due to the high volume of data being written and the query patterns to access that data. This article doesn’t intend to make the case for which database is better; it simply provides an overview of each database so you can make an informed decision.

Redis vs OpenTSDB Breakdown


 
Database Model

In-memory database

Time series database

Architecture

Redis can be deployed on-premises, in the cloud, or as a managed service

OpenTSDB can be deployed on-premises or in the cloud, with HBase running on a distributed cluster of nodes.

License

BSD 3

GNU LGPLv2.1

Use Cases

Caching, message brokering, real-time analytics, session storage, geospatial data processing

Monitoring, observability, IoT, log data storage

Scalability

Horizontally scalable via partitioning and clustering, supports data replication

Horizontally scalable across multiple nodes using HBase as its storage backend

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Redis Overview

Redis, which stands for Remote Dictionary Server, is an open-source, in-memory data structure store that can be used as a database, cache, and message broker. It was created by Salvatore Sanfilippo in 2009 and has since gained significant popularity due to its high performance and flexibility. Redis supports various data structures, such as strings, hashes, lists, sets, sorted sets with range queries, bitmaps, hyperloglogs, and geospatial indexes with radius queries.

OpenTSDB Overview

OpenTSDB (Open Time Series Database) is an open-source, distributed, and scalable time series database built on top of Apache HBase, a NoSQL database. OpenTSDB was designed to address the growing need for storing and processing large volumes of time series data generated by various sources, such as IoT devices, sensors, and monitoring systems. It was initially developed by StumbleUpon in 2010 and later became an independent project with an active community of contributors.


Redis for Time Series Data

Redis has a dedicated module for working with time series data called RedisTimeSeries. RedisTimeSeries offers functionality like downsampling, data retention policies, and specialized queries for time series data in Redis. Being an in-memory database, Redis will be very fast for reading and writing time series data, but due to the cost of RAM compared to disk using Redis could become expensive depending on the size of your dataset. If your use case doesn’t require extremely fast response times, you could save money by going with a more traditional time series database.

OpenTSDB for Time Series Data

OpenTSDB is designed for time series data storage and analysis, making it an ideal choice for managing large scale time series datasets. Its architecture enables high write and query performance, and it can handle millions of data points per second with minimal resource consumption. OpenTSDB’s flexible querying capabilities allow users to perform complex analysis on time series data efficiently.


Redis Key Concepts

  • In-memory store: Redis stores data in memory, which allows for faster data access and manipulation compared to disk-based databases .
  • Data structures: Redis supports a wide range of data structures, including strings, hashes, lists, sets, and more, which provide flexibility in how data is modeled and stored.
  • Persistence: Redis offers optional data persistence, allowing data to be periodically saved to disk or written to a log for durability.
  • Pub/Sub: Redis provides a publish/subscribe messaging system, enabling real-time communication between clients without the need for a centralized message broker.

OpenTSDB Key Concepts

  • Data Point: A single measurement in time consisting of a timestamp, metric, value, and associated tags.
  • Metric: A named value that represents a specific aspect of a system, such as CPU usage or temperature.
  • Tags: Key-value pairs associated with data points that provide metadata and help categorize and query the data.


Redis Architecture

Redis is a NoSQL database that uses a key-value data model, where each key is associated with a value stored as one of Redis’ supported data structures. The database is single-threaded, which simplifies its internal architecture and reduces contention. Redis can be deployed as a standalone server, a cluster, or a master-replica setup for scalability and high availability. The Redis Cluster mode automatically shards data across multiple nodes, providing data partitioning and fault tolerance.

OpenTSDB Architecture

OpenTSDB is built on top of Apache HBase, a distributed and scalable NoSQL database, and relies on its architecture for data storage and management. OpenTSDB stores time series data in HBase tables, with data points organized by metric, timestamp, and tags. The database uses a schema-less data model, which allows for flexibility when adding new metrics and tags. The OpenTSDB architecture also supports horizontal scaling by distributing data across multiple HBase nodes.

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Redis Features

Atomicity

Redis supports atomic operations on complex data types, allowing developers to perform powerful operations without worrying about race conditions or other concurrent processing issues.

Broad data structure support

Redis supports a range of data structures such as lists, sets, sorted sets, hashes, bitmaps, hyperloglog, and geospatial indexes. This flexibility allows developers to use Redis for a wide variety of tasks by using data structures that are optimized for their data in terms of performance characteristics.

Pub/Sub messaging

Redis provides a publish/subscribe messaging system for real-time communication between clients.

Lua Scripting

Developers can run Lua scripts in the Redis server, enabling complex operations to be executed atomically in the server itself, reducing network round trips.

OpenTSDB Features

Scalability

OpenTSDB’s distributed architecture allows for horizontal scaling, ensuring that the database can handle growing volumes of time series data.

Data Compression

OpenTSDB uses various compression techniques to reduce the storage footprint of time series data.

Query Language with time series support

OpenTSDB features a flexible query language that supports aggregation, downsampling, filtering, and other operations for analyzing time series data.


Redis Use Cases

Caching

Redis is often used as a cache to store frequently accessed data and reduce the load on other databases or services, improving application performance and reducing latency.

Task queues

Redis can be used to implement task queues, which are useful for managing tasks that take longer to process and should be executed asynchronously. This is particularly common in web applications, where background tasks can be processed independently of the request/response cycle

Real-time analysis and machine learning

Redis’ high performance and low-latency data access make it suitable for real-time analysis and machine learning applications, such as processing streaming data, media streaming, and handling time-series data. This can be achieved using Redis’ data structures and capabilities like sorted sets, timestamps, and pub/sub messaging.

OpenTSDB Use Cases

Monitoring and Alerting

OpenTSDB is well-suited for large-scale monitoring and alerting systems that generate vast amounts of time series data from various sources.

IoT Data Storage

OpenTSDB can store and analyze time series data generated by IoT devices, such as sensors and smart appliances, enabling real-time insights and analytics.

Performance Analysis

OpenTSDB’s flexible querying capabilities make it an ideal choice for analyzing system and application performance metrics over time.


Redis Pricing Model

Redis is open-source software, which means it can be deployed and used freely on your own infrastructure. However, there are also managed Redis services available, such as Redis Enterprise which offer additional features, support, and ease of deployment. Pricing for these services typically depends on factors like the size of the instance, data storage, and data transfer.

OpenTSDB Pricing Model

OpenTSDB is open-source software, which means it is free to use without any licensing fees. However, the cost of running OpenTSDB depends on the infrastructure required to support the underlying HBase database, such as cloud services or on-premises hardware.