SingleStore
activeby SingleStore, Inc. · since 2013 · also known as MemSQL, SingleStoreDB, SingleStore Helios
Distributed SQL mixing in-memory rowstore and columnstore for real-time analytics, search and vectors.
Overview
SingleStore (formerly MemSQL) is a distributed, MySQL-wire-compatible database whose Universal Storage combines an in-memory rowstore with a compressed, disk-based columnstore that still supports fast seeks and updates. Built-in pipelines ingest continuously from Kafka, S3 and other sources, and the engine adds full-text and indexed vector search, so a single cluster can power customer-facing dashboards and AI features over fresh data. It is offered as Helios (managed, with a free shared tier) and as self-managed software. Since a 2025 growth buyout, private-equity firm Vector Capital holds a majority stake. Expect commercial licensing and some MySQL incompatibilities such as missing triggers.
Strengths & trade-offs
Strengths
- +Columnstore with seekable, updatable segments serves both point lookups and large scans
- +Native pipelines ingest from Kafka, S3 and GCS with exactly-once semantics
- +Indexed vector search (HNSW/IVF, F16 vectors in 9.1) next to SQL and full-text
- +MySQL wire compatibility simplifies driver and BI tool support
- +Sub-second analytics on high-concurrency, customer-facing dashboards
Trade-offs
- −Proprietary license; self-managed production use is costly
- −No triggers or materialized views; some MySQL syntax unsupported
- −Rowstore tables require data to fit in memory
- −Shard key and sort key choices strongly affect performance
Great for
- +Real-time customer-facing analytics
- +Fraud detection and risk scoring on streaming data
- +Ad-tech and IoT ingestion with immediate querying
- +Hybrid vector plus keyword search for RAG
- +Replacing a MySQL + Elasticsearch + warehouse combination
Think twice for
- −Simple CRUD apps that fit in Postgres or MySQL
- −Teams needing an open-source license
- −Workloads dependent on triggers
Capabilities
Native or official first-party support · 17 of 25 tracked
Scale & consistency
- Comfortable data size
- Large · ≤ 1 PB
- Horizontal scaling
- Native
- Multi-region
- Read replicas
- Transactions
- Full ACID
- Consistency
- Strong
- Schema
- Strict
- Architecture
- Distributed, In memory, Client server
- Query languages
- SQL, MPSQL (stored procedures)
Aggregator/leaf architecture with hash-sharded partitions; Helios separates storage onto object storage (bottomless); cross-region DR replication.
Deployment
available on · AWS · Google Cloud · Azure
Ecosystem
Alternatives to SingleStore
MySQL-compatible distributed SQL with a row store for OLTP and a columnar replica for real-time analytics.
singlestore vs tidb →Open-source columnar OLAP database known for very fast aggregations over billions of rows.
singlestore vs clickhouse →Real-time OLAP store from LinkedIn for user-facing analytics at very high query rates.
singlestore vs apache-pinot →MPP OLAP database with a fast vectorized engine, real-time upserts and native lakehouse queries.
singlestore vs starrocks →Alipay-proven distributed SQL with MySQL (and Oracle, in Enterprise) compatibility, HTAP and vector search.
singlestore vs oceanbase →The extensible, standards-first open-source relational database.
singlestore vs postgresql →SingleStore FAQ
What is SingleStore?
SingleStore is a relational database by SingleStore, Inc., first released in 2013. SingleStore (formerly MemSQL) is a distributed, MySQL-wire-compatible database whose Universal Storage combines an in-memory rowstore with a compressed, disk-based columnstore that still supports fast seeks and updates. Built-in pipelines ingest continuously from Kafka, S3 and other sources, and the engine adds full-text and indexed vector search, so a single cluster can power customer-facing dashboards and AI features over fresh data. It is offered as Helios (managed, with a free shared tier) and as self-managed software. Since a 2025 growth buyout, private-equity firm Vector Capital holds a majority stake. Expect commercial licensing and some MySQL incompatibilities such as missing triggers.
Is SingleStore open source?
No. SingleStore is proprietary, closed-source software.
Does SingleStore support ACID transactions?
Yes. SingleStore supports full ACID transactions, with strong consistency.
Does SingleStore scale horizontally?
SingleStore scales horizontally out of the box, with built-in sharding or partitioning. It is comfortable at large scale (≤ 1 PB). It supports cross-region read replicas.
How can I run SingleStore?
You can self-host it and use the vendor's managed cloud. Managed offerings include SingleStore Helios. It is available on AWS, Google Cloud and Azure.
What is SingleStore best for?
SingleStore is a strong fit for real-time customer-facing analytics; fraud detection and risk scoring on streaming data; and ad-tech and IoT ingestion with immediate querying. Think twice for simple CRUD apps that fit in Postgres or MySQL.
What are the best alternatives to SingleStore?
Common alternatives to SingleStore include TiDB, ClickHouse, Apache Pinot, StarRocks and OceanBase. The right choice depends on your workload, scale and hosting; WhichDB's smart match ranks them against your requirements.
How popular is SingleStore?
SingleStore ranks #92 of 844 databases on the WhichDB Score (29.0/100), and #30 among relational databases. The score combines public adoption signals such as package downloads, GitHub activity, job posts and developer discussion.