heavy

README

General concept

For general concept explanation one can refer to /pkg/core/database/README.md. This document must focus on decisions made with regard to goleveldb specifics

K/V storage schema to store a single pkg/core/block.Block into blockchain

Prefix	KEY	VALUE	Count	Used by
0x01	HeaderHash	Header.Encode()	1 per block
0x02	HeaderHash + TxID	TxIndex + Tx.Encode()	block txs count
0x04	TxID	HeaderHash	block txs count	FetchBlockTxByHash
0x05	KeyImage	TxID	sum of block txs inputs	FetchKeyImageExists
0x03	Height	HeaderHash	1 per block	FetchBlockHashByHeight
0x07	State	Chain tip hash	1 per chain	FetchState

K/V storage schema to store a candidate pkg/core/block.Block

Prefix	KEY	VALUE	Count	Used by
0x06	HeaderHash + Height	Block.Encode()	Many per blockchain	Store/Fetch/Delete CandidateBlock

Table notation

• HeaderHash - a calculated hash of block header
• TxID - a calculated hash of transaction
• '+' operation - denotes concatenation of byte arrays
• Tx.Encode() - Encoded binary form of all Tx fields without TxID

Documentation

Index

• Variables
• func CreateDBConnection() (database.Driver, database.DB)
• func NewDatabase(path string, network protocol.Magic, readonly bool) (database.DB, error)
• type DB
  • func (db DB) Begin(writable bool) (database.Transaction, error)
  • func (db DB) Close() error
  • func (db DB) GetSnapshot() (*leveldb.Snapshot, error)
  • func (db DB) Update(fn func(database.Transaction) error) error
  • func (db DB) View(fn func(database.Transaction) error) error

Variables

var (
	HeaderPrefix    = []byte{0x01}
	TxPrefix        = []byte{0x02}
	HeightPrefix    = []byte{0x03}
	TxIDPrefix      = []byte{0x04}
	KeyImagePrefix  = []byte{0x05}
	StatePrefix     = []byte{0x06}
	OutputKeyPrefix = []byte{0x07}
	BidValuesPrefix = []byte{0x08}
)

var (
	// DriverName is the unique identifier for the heavy driver
	DriverName = "heavy_v0.1.0"
)

Functions

func CreateDBConnection

func CreateDBConnection() (database.Driver, database.DB)

func NewDatabase

func NewDatabase(path string, network protocol.Magic, readonly bool) (database.DB, error)

NewDatabase create or open backend storage (goleveldb) located at the specified path. Readonly option is pseudo read-only mode implemented by heavy.Database. Not to be confused with read-only goleveldb mode

Types

type DB

type DB struct {
	// contains filtered or unexported fields
}

DB on top of underlying storage syndtr/goleveldb/leveldb

func (DB) Begin

func (db DB) Begin(writable bool) (database.Transaction, error)

Begin builds read-only or read-write Transaction

func (DB) Close

func (db DB) Close() error

Close does not close the underlying storage as we need to reuse it within another DB instances. Note that we rely on the Finalizer that goleveldb is setting at the point of leveldb.DB.openDB to call leveldb.DB.Close() when the process is terminating

func (DB) GetSnapshot

func (db DB) GetSnapshot() (*leveldb.Snapshot, error)

GetSnapshot returns current storage snapshot. To be used only by database/testing pkg

func (DB) Update

func (db DB) Update(fn func(database.Transaction) error) error

func (DB) View

func (db DB) View(fn func(database.Transaction) error) error