| PackageDescription |
The Memdb package implements a simple in-memory database built on immutable
radix trees. The database provides Atomicity, Consistency and Isolation from
ACID. Being that it is in-memory, it does not provide durability. The database
is instantiated with a schema that specifies the tables and indices that exist
and allows transactions to be executed.
The database provides the following:
- Multi-Version Concurrency Control (MVCC) - By leveraging immutable radix
trees the database is able to support any number of concurrent readers
without locking, and allows a writer to make progress.
- Transaction Support - The database allows for rich transactions, in which
multiple objects are inserted, updated or deleted. The transactions can span
multiple tables, and are applied atomically. The database provides atomicity
and isolation in ACID terminology, such that until commit the updates are not
visible.
- Rich Indexing - Tables can support any number of indexes, which can be simple
like a single field index, or more advanced compound field indexes. Certain
types like UUID can be efficiently compressed from strings into byte indexes
for reduced storage requirements.
- Watches - Callers can populate a watch set as part of a query, which can be
used to detect when a modification has been made to the database which
affects the query results. This lets callers easily watch for changes in the
database in a very general way. |