Crate reth_db

reth’s database abstraction layer with concrete implementations.

The database abstraction assumes that the underlying store is a KV store subdivided into tables.

One or more changes are tied to a transaction that is atomically committed to the data store at the same time. Strong consistency in what data is written and when is important for reth, so it is not possible to write data to the database outside of using a transaction.

Good starting points for this crate are:

• Database for the main database abstraction
• DbTx (RO) and DbTxMut (RW) for the transaction abstractions.
• DbCursorRO (RO) and DbCursorRW (RW) for the cursor abstractions (see below).

Cursors and Walkers

The abstraction also defines a couple of helpful abstractions for iterating and writing data:

• Cursors (DbCursorRO / DbCursorRW) for iterating data in a table. Cursors are assumed to resolve data in a sorted manner when iterating from start to finish, and it is safe to assume that they are efficient at doing so.
• Walkers (Walker / RangeWalker / ReverseWalker) use cursors to walk the entries in a table, either fully from a specific point, or over a range.

Dup tables (see below) also have corresponding cursors and walkers (e.g. DbDupCursorRO). These should be preferred when working with dup tables, as they provide additional methods that are optimized for dup tables.

Tables

reth has two types of tables: simple KV stores (one key, one value) and dup tables (one key, many values). Dup tables can be efficient for certain types of data.

Keys are de/serialized using the Encode and Decode traits, and values are de/serialized (“compressed”) using the Compress and Decompress traits.

Tables implement the Table trait.

Overview

An overview of the current data model of reth can be found in the tables module.

Re-exports

• pub use mdbx::DatabaseEnv;
• pub use mdbx::DatabaseEnvKind;
• pub use abstraction::*;
• pub use tables::*;

Modules

• abstraction
  Traits defining the database abstractions, such as cursors and transactions.
• mdbxmdbx
  Bindings for MDBX.
• snapshot
  reth’s snapshot database table import and access
• tables
  Tables and data models.
• test_utilstest-utils
  Collection of database test utilities
• version
  Database version utils.

Macros

• add_snapshot_mask
  Add mask to select N column values from a specific snapshot segment row.
• decodemdbx
  Takes (key, value) from the database and decodes it appropriately.
• dupsort
  Macro to declare duplicate key value table.
• impl_fixed_arbitrary
  Implements the Arbitrary trait for types with fixed array types.
• table
  Macro to declare key value table.

Enums

• DatabaseError
  Database error type.
• DatabaseWriteOperation
  Database write operation type.

Functions

• init_db
  Opens up an existing database or creates a new one at the specified path. Creates tables if necessary. Read/Write mode.
• is_database_empty
  Check if a db is empty. It does not provide any information on the validity of the data in it. We consider a database as non empty when it’s a non empty directory.
• open_db
  Opens up an existing database. Read/Write mode with WriteMap enabled. It doesn’t create it or create tables if missing.
• open_db_read_only
  Opens up an existing database. Read only mode. It doesn’t create it or create tables if missing.