memds

Memory database - "redis v3, in Rust"

Goals and Journey

memds intends to be "the next thing after redis"

Looking through software history, we can consider memcached as Version 1: memcached provides a single key/value namespace for string values, plus some small mods for atomic numbers. redis is Version 2: Differences between abstract data types (ADTs) are made explicit with strings, sets, lists, hash [tables], streams and more.

memds is Version 3: Formally model the network protocol and database namespace. Represent abstract data types as CLASS.METHOD internal Remote Procedure Calls (RPCs), batched together as a bytecode-like stream of database mutation operations.

Model & design comparisons

(note: the current code is still a work in progress, in terms of implementing this)

Old redis model:

     [database number] [key] [abstract data type]

New memds model:

     [database key] [key] [abstract data type, possibly with its own hierarchy]

Old redis protocol hierarchy: All ADTs overloaded in a single command namespace ("HLEN","LLEN"). New memds protocol hierarchy: Each ADT in its own class-specific namespace. (like "HASH.LEN","LIST.LEN", but with integer identifiers).

Old redis network protocol: Custom protocol, requiring custom clients across N programming languages. New memds network protocol: Protobuf schema, automatically generating correct, compliant, fast client codecs for many languages.

Components

• memds-cli: Command line client
• memds-proto: wire protocol library
• memds-server: Database server

Installation

All building is done via the standard Rust tool Cargo.

$ cargo build --release
$ cargo test --release