# kv_engine

**Repository Path**: mirrors_couchbase/kv_engine

## Basic Information

- **Project Name**: kv_engine
- **Description**: Couchbase Key-Value Engine
- **Primary Language**: Unknown
- **License**: Not specified
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2020-08-08
- **Last Updated**: 2026-05-23

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# KV-Engine

Welcome to the Couchbase _KV-Engine_ project.

This started as Couchbase's fork of the upstream `memcached` project,
but has substantially evolved since then. It contains the bulk of the
code for the Key/Value service of Couchbase Server.

## Repository Layout

Areas of interest in the repository:

* [`include/`](include/) - Public header files.
* `daemon/` - Source for the main daemon process (also known as the
  _server_). This is where [`main()`](daemon/memcached.cc) lives.
* `engines/` - Source for the different engines (aka bucket types)
  supported. Includes:
    * [`ep`](engines/ep/) - _Eventually Persistent_ Engine. Powers the
    _Couchbase_ and _Ephemeral_ bucket types.
    * [`ewouldblock engine`](engines/ewouldblock_engine) - Test engine
      which interposes a real engine and can perform various types of
      error-injection.
* `tests/` - Test cases.
* `licenses/` - The various licenses in use

## Building

KV-Engine has a number of external dependencies, as such it should be
built via the Couchbase
[top-level Makefile](https://github.com/couchbase/tlm).

## Documentation

### Architecture

* [KV-Engine Architecture](docs/Architecture.md)
* [CBSASL](cbsasl/CBSASL.md)
* [Connections](docs/Connections.md)
* [Audit](auditd/README.md)
* [Event Tracing / Phosphor](docs/Tracing.md)
* [Document size limits](docs/DocumentSizeLimits.md)
* [Document attributes](docs/Document.md)
* [Environment variables](docs/EnvironmentVariables.md)
* [Frontend Worker Threads](docs/FrontendWorkerThread.md)
* [Role Based Access Control (RBAC)](docs/rbac.md)
* [SSL Client Certificate](docs/ssl_client_cert.md)
* [DCP](docs/dcp/README.md)
* [Network interfaces](docs/NetworkInterface.md)
* [HiFi MFU Eviction Policy](docs/HiFi_MFU_eviction_policy.md)
* [Throttling](docs/Throttling.md)
* [Top Keys](docs/Topkeys.md)
* [Bucket Configuration](docs/BucketConfiguration.md)

### Protocols

* [Memcached Binary Protocol](docs/BinaryProtocol.md)
    * [SASL](docs/sasl.md)
    * [Duplex mode](docs/Duplex.md)
    * [External Authentication Provider](docs/ExternalAuthProvider.md)
    * [DCP](docs/dcp/documentation/protocol.md)
    * [Subdoc](docs/SubDocument.md)

### Policies / Guidelines

* [Coding Standards](docs/CodingStandards.rst)
* [Error Handling Best Practices](docs/ErrorHandling.md)
* [File ownership in bucket data directory](docs/BucketDataDirectory.md)

### Debugging on Windows

* [Hints on how to debug a minidump file with WinDbg](docs/WinDbgHints.md)

## Tools

* [Analyze jemalloc memory statistics](scripts/jemalloc/README.md)

## Related Projects

While the bulk of code making up KV-Engine is in this repo, there are
a number of other repositories which contribute to the final program:

* [`couchbase/couchstore`](https://github.com/couchbase/couchstore) -
  Couchbase storage file library.
* [`couchbase/phosphor`](https://github.com/couchbase/phosphor) -
  Phosphor: high performance event tracing framework.
* [`couchbase/platform`](https://github.com/couchbase/platform) -
  Platform abstraction layer.
* [`couchbase/subjson`](https://github.com/couchbase/subjson) -
  subjson - quickly manipulate JSON subfields.