whichdb
vs

cdb vs RocksDB

cdb: D. J. Bernstein's constant database: immutable on-disk hash tables with two-read lookups and atomic swaps. RocksDB: Meta's embeddable LSM-tree key-value engine, the storage layer under dozens of databases.

key differences

  • RocksDB is built for larger datasets (≤ 10 TB) than cdb (≤ 100 GB).
  • Transactions: cdb offers limited ACID; RocksDB offers full.
  • Only RocksDB has transactions, ttl / expiry, compression.

choose cdb for

  • +Mail and DNS server lookup tables
  • +Read-only configuration or routing maps rebuilt in batches
  • +Static key/value datasets shipped with an application

best at · Embedded, Coordination, Metadata

choose rocksdb for

  • +Storage engine for a custom database or service
  • +Stream-processing state stores (Kafka Streams, Flink)
  • +MySQL storage engine via MyRocks
  • +Write-heavy local indexes and caches on SSD

best at · Embedded, OLTP, Streaming

cdbD. J. Bernstein's constant database: immutable on-disk hash tables with two-read lookups and atomic swaps.
RocksDBMeta's embeddable LSM-tree key-value engine, the storage layer under dozens of databases.
overview
Primary model
Key-Value
Key-Value
Also supports
–
–
Type
Embedded library
Embedded library
Status
Active
Active
Developer
D. J. Bernstein
Meta
First release
1996
2013
Latest version
20251021 (Oct 21, 2025)
11.12 (Oct 26, 2026)
License
Open source (permissive)Public domain
Open source (permissive)Apache License 2.0 or GPL-2.0 (dual)
Free tier
✓
✓
popularity
WhichDB Score
3.5
48.2
Rank
#434
#30
GitHub stars
–
32.2K
Stack Overflow questions
–
504
scale & guarantees
Comfortable data size
Small (≤ 100 GB)
Medium (≤ 10 TB)
Horizontal scaling
None
None
Multi-region
None
None
ACID
Limited
Full
Consistency
Strong
Strong
Schema
Schemaless
Schemaless
Architecture
Embedded
Embedded
deployment
Self-hosted
✓
✓
Vendor-managed cloud
—
—
Serverless
—
—
Embedded
✓
✓
Edge
—
—
Clouds
–
–
capabilities
Transactions
—
✓
Joins
—
—
Secondary indexes
—
—
Full-text search
—
—
Vector search
—
—
Geospatial
—
—
JSON
—
—
Change data capture
—
—
Triggers
—
—
Stored procedures
—
—
Materialized views
—
—
TTL / expiry
—
✓
Pub/Sub
—
—
Columnar storage
—
—
In-memory
—
—
Durable persistence
✓
✓
Compression
—
✓
Encryption at rest
—
—
Role-based access
—
—
Time travel
—
—
Branching
—
—
Online schema changes
—
—
Streaming ingest
—
—
Offline sync
—
—
Runs in WebAssembly
—
—
interfaces
Query languages
C API
C++ API
Client languages
C, Go, Rust, Perl, Python, Ruby, Haskell
C++, C, Java
Best for
Embedded, Coordination, Metadata
Embedded, OLTP, Streaming, Metadata
Add more to this comparisonNot sure either fits? Try smart match

cdb vs RocksDB: FAQ

What is the difference between cdb and RocksDB?

cdb: D. J. Bernstein's constant database: immutable on-disk hash tables with two-read lookups and atomic swaps. RocksDB: Meta's embeddable LSM-tree key-value engine, the storage layer under dozens of databases. RocksDB is built for larger datasets (≤ 10 TB) than cdb (≤ 100 GB). Transactions: cdb offers limited ACID; RocksDB offers full. Only RocksDB has transactions, ttl / expiry, compression.

When should I choose cdb over RocksDB?

Choose cdb for mail and DNS server lookup tables; read-only configuration or routing maps rebuilt in batches; and static key/value datasets shipped with an application. Choose RocksDB for storage engine for a custom database or service; stream-processing state stores (Kafka Streams, Flink); and MySQL storage engine via MyRocks.

Is cdb or RocksDB more popular?

RocksDB ranks #30 on the WhichDB Score (48.2/100) and cdb ranks #434 (3.5/100). Popularity is not fit: check the requirements that matter for your project.

Are cdb and RocksDB open source?

Yes. cdb is open source. License: Public domain. Yes. RocksDB is open source. License: Apache License 2.0 or GPL-2.0 (dual).