tm-db: github.com/tendermint/tm-db Index | Files | Directories

package db

import "github.com/tendermint/tm-db"

Index

Package Files

db.go goleveldb.go goleveldb_batch.go goleveldb_iterator.go memdb.go memdb_batch.go memdb_iterator.go prefixdb.go prefixdb_batch.go prefixdb_iterator.go test_helpers.go types.go util.go

func FileExists Uses

func FileExists(filePath string) bool

func IsKeyInDomain Uses

func IsKeyInDomain(key, start, end []byte) bool

See DB interface documentation for more information.

type BackendType Uses

type BackendType string
const (
    // GoLevelDBBackend represents goleveldb (github.com/syndtr/goleveldb - most
    // popular implementation)
    //   - pure go
    //   - stable
    GoLevelDBBackend BackendType = "goleveldb"
    // CLevelDBBackend represents cleveldb (uses levigo wrapper)
    //   - fast
    //   - requires gcc
    //   - use cleveldb build tag (go build -tags cleveldb)
    CLevelDBBackend BackendType = "cleveldb"
    // MemDBBackend represents in-memory key value store, which is mostly used
    // for testing.
    MemDBBackend BackendType = "memdb"
    // BoltDBBackend represents bolt (uses etcd's fork of bolt -
    // github.com/etcd-io/bbolt)
    //   - EXPERIMENTAL
    //   - may be faster is some use-cases (random reads - indexer)
    //   - use boltdb build tag (go build -tags boltdb)
    BoltDBBackend BackendType = "boltdb"
    // RocksDBBackend represents rocksdb (uses github.com/tecbot/gorocksdb)
    //   - EXPERIMENTAL
    //   - requires gcc
    //   - use rocksdb build tag (go build -tags rocksdb)
    RocksDBBackend BackendType = "rocksdb"
)

These are valid backend types.

type Batch Uses

type Batch interface {
    // Set sets a key/value pair.
    // CONTRACT: key, value readonly []byte
    Set(key, value []byte) error

    // Delete deletes a key/value pair.
    // CONTRACT: key readonly []byte
    Delete(key []byte) error

    // Write writes the batch, possibly without flushing to disk. Only Close() can be called after,
    // other methods will error.
    Write() error

    // WriteSync writes the batch and flushes it to disk. Only Close() can be called after, other
    // methods will error.
    WriteSync() error

    // Close closes the batch. It is idempotent, but calls to other methods afterwards will error.
    Close() error
}

Batch represents a group of writes. They may or may not be written atomically depending on the backend. Callers must call Close on the batch when done.

As with DB, given keys and values should be considered read-only, and must not be modified after passing them to the batch.

type DB Uses

type DB interface {
    // Get fetches the value of the given key, or nil if it does not exist.
    // CONTRACT: key, value readonly []byte
    Get([]byte) ([]byte, error)

    // Has checks if a key exists.
    // CONTRACT: key, value readonly []byte
    Has(key []byte) (bool, error)

    // Set sets the value for the given key, replacing it if it already exists.
    // CONTRACT: key, value readonly []byte
    Set([]byte, []byte) error

    // SetSync sets the value for the given key, and flushes it to storage before returning.
    SetSync([]byte, []byte) error

    // Delete deletes the key, or does nothing if the key does not exist.
    // CONTRACT: key readonly []byte
    Delete([]byte) error

    // DeleteSync deletes the key, and flushes the delete to storage before returning.
    DeleteSync([]byte) error

    // Iterator returns an iterator over a domain of keys, in ascending order. The caller must call
    // Close when done. End is exclusive, and start must be less than end. A nil start iterates
    // from the first key, and a nil end iterates to the last key (inclusive). Empty keys are not
    // valid.
    // CONTRACT: No writes may happen within a domain while an iterator exists over it.
    // CONTRACT: start, end readonly []byte
    Iterator(start, end []byte) (Iterator, error)

    // ReverseIterator returns an iterator over a domain of keys, in descending order. The caller
    // must call Close when done. End is exclusive, and start must be less than end. A nil end
    // iterates from the last key (inclusive), and a nil start iterates to the first key (inclusive).
    // Empty keys are not valid.
    // CONTRACT: No writes may happen within a domain while an iterator exists over it.
    // CONTRACT: start, end readonly []byte
    ReverseIterator(start, end []byte) (Iterator, error)

    // Close closes the database connection.
    Close() error

    // NewBatch creates a batch for atomic updates. The caller must call Batch.Close.
    NewBatch() Batch

    // Print is used for debugging.
    Print() error

    // Stats returns a map of property values for all keys and the size of the cache.
    Stats() map[string]string
}

DB is the main interface for all database backends. DBs are concurrency-safe. Callers must call Close on the database when done.

Keys cannot be nil or empty, while values cannot be nil. Keys and values should be considered read-only, both when returned and when given, and must be copied before they are modified.

func NewDB Uses

func NewDB(name string, backend BackendType, dir string) (DB, error)

NewDB creates a new database of type backend with the given name.

type GoLevelDB Uses

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

func NewGoLevelDB Uses

func NewGoLevelDB(name string, dir string) (*GoLevelDB, error)

func NewGoLevelDBWithOpts Uses

func NewGoLevelDBWithOpts(name string, dir string, o *opt.Options) (*GoLevelDB, error)

func (*GoLevelDB) Close Uses

func (db *GoLevelDB) Close() error

Close implements DB.

func (*GoLevelDB) DB Uses

func (db *GoLevelDB) DB() *leveldb.DB

func (*GoLevelDB) Delete Uses

func (db *GoLevelDB) Delete(key []byte) error

Delete implements DB.

func (*GoLevelDB) DeleteSync Uses

func (db *GoLevelDB) DeleteSync(key []byte) error

DeleteSync implements DB.

func (*GoLevelDB) Get Uses

func (db *GoLevelDB) Get(key []byte) ([]byte, error)

Get implements DB.

func (*GoLevelDB) Has Uses

func (db *GoLevelDB) Has(key []byte) (bool, error)

Has implements DB.

func (*GoLevelDB) Iterator Uses

func (db *GoLevelDB) Iterator(start, end []byte) (Iterator, error)

Iterator implements DB.

func (*GoLevelDB) NewBatch Uses

func (db *GoLevelDB) NewBatch() Batch

NewBatch implements DB.

func (*GoLevelDB) Print Uses

func (db *GoLevelDB) Print() error

Print implements DB.

func (*GoLevelDB) ReverseIterator Uses

func (db *GoLevelDB) ReverseIterator(start, end []byte) (Iterator, error)

ReverseIterator implements DB.

func (*GoLevelDB) Set Uses

func (db *GoLevelDB) Set(key []byte, value []byte) error

Set implements DB.

func (*GoLevelDB) SetSync Uses

func (db *GoLevelDB) SetSync(key []byte, value []byte) error

SetSync implements DB.

func (*GoLevelDB) Stats Uses

func (db *GoLevelDB) Stats() map[string]string

Stats implements DB.

type Iterator Uses

type Iterator interface {
    // Domain returns the start (inclusive) and end (exclusive) limits of the iterator.
    // CONTRACT: start, end readonly []byte
    Domain() (start []byte, end []byte)

    // Valid returns whether the current iterator is valid. Once invalid, the Iterator remains
    // invalid forever.
    Valid() bool

    // Next moves the iterator to the next key in the database, as defined by order of iteration.
    // If Valid returns false, this method will panic.
    Next()

    // Key returns the key at the current position. Panics if the iterator is invalid.
    // CONTRACT: key readonly []byte
    Key() (key []byte)

    // Value returns the value at the current position. Panics if the iterator is invalid.
    // CONTRACT: value readonly []byte
    Value() (value []byte)

    // Error returns the last error encountered by the iterator, if any.
    Error() error

    // Close closes the iterator, relasing any allocated resources.
    Close() error
}

Iterator represents an iterator over a domain of keys. Callers must call Close when done. No writes can happen to a domain while there exists an iterator over it, some backends may take out database locks to ensure this will not happen.

Callers must make sure the iterator is valid before calling any methods on it, otherwise these methods will panic. This is in part caused by most backend databases using this convention.

As with DB, keys and values should be considered read-only, and must be copied before they are modified.

Typical usage:

var itr Iterator = ... defer itr.Close()

for ; itr.Valid(); itr.Next() {

k, v := itr.Key(); itr.Value()
...

} if err := itr.Error(); err != nil {

...

}

func IteratePrefix Uses

func IteratePrefix(db DB, prefix []byte) (Iterator, error)

IteratePrefix is a convenience function for iterating over a key domain restricted by prefix.

type MemDB Uses

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

MemDB is an in-memory database backend using a B-tree for storage.

For performance reasons, all given and returned keys and values are pointers to the in-memory database, so modifying them will cause the stored values to be modified as well. All DB methods already specify that keys and values should be considered read-only, but this is especially important with MemDB.

func NewMemDB Uses

func NewMemDB() *MemDB

NewMemDB creates a new in-memory database.

func (*MemDB) Close Uses

func (db *MemDB) Close() error

Close implements DB.

func (*MemDB) Delete Uses

func (db *MemDB) Delete(key []byte) error

Delete implements DB.

func (*MemDB) DeleteSync Uses

func (db *MemDB) DeleteSync(key []byte) error

DeleteSync implements DB.

func (*MemDB) Get Uses

func (db *MemDB) Get(key []byte) ([]byte, error)

Get implements DB.

func (*MemDB) Has Uses

func (db *MemDB) Has(key []byte) (bool, error)

Has implements DB.

func (*MemDB) Iterator Uses

func (db *MemDB) Iterator(start, end []byte) (Iterator, error)

Iterator implements DB. Takes out a read-lock on the database until the iterator is closed.

func (*MemDB) NewBatch Uses

func (db *MemDB) NewBatch() Batch

NewBatch implements DB.

func (*MemDB) Print Uses

func (db *MemDB) Print() error

Print implements DB.

func (*MemDB) ReverseIterator Uses

func (db *MemDB) ReverseIterator(start, end []byte) (Iterator, error)

ReverseIterator implements DB. Takes out a read-lock on the database until the iterator is closed.

func (*MemDB) Set Uses

func (db *MemDB) Set(key []byte, value []byte) error

Set implements DB.

func (*MemDB) SetSync Uses

func (db *MemDB) SetSync(key []byte, value []byte) error

SetSync implements DB.

func (*MemDB) Stats Uses

func (db *MemDB) Stats() map[string]string

Stats implements DB.

type PrefixDB Uses

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

PrefixDB wraps a namespace of another database as a logical database.

func NewPrefixDB Uses

func NewPrefixDB(db DB, prefix []byte) *PrefixDB

NewPrefixDB lets you namespace multiple DBs within a single DB.

func (*PrefixDB) Close Uses

func (pdb *PrefixDB) Close() error

Close implements DB.

func (*PrefixDB) Delete Uses

func (pdb *PrefixDB) Delete(key []byte) error

Delete implements DB.

func (*PrefixDB) DeleteSync Uses

func (pdb *PrefixDB) DeleteSync(key []byte) error

DeleteSync implements DB.

func (*PrefixDB) Get Uses

func (pdb *PrefixDB) Get(key []byte) ([]byte, error)

Get implements DB.

func (*PrefixDB) Has Uses

func (pdb *PrefixDB) Has(key []byte) (bool, error)

Has implements DB.

func (*PrefixDB) Iterator Uses

func (pdb *PrefixDB) Iterator(start, end []byte) (Iterator, error)

Iterator implements DB.

func (*PrefixDB) NewBatch Uses

func (pdb *PrefixDB) NewBatch() Batch

NewBatch implements DB.

func (*PrefixDB) Print Uses

func (pdb *PrefixDB) Print() error

Print implements DB.

func (*PrefixDB) ReverseIterator Uses

func (pdb *PrefixDB) ReverseIterator(start, end []byte) (Iterator, error)

ReverseIterator implements DB.

func (*PrefixDB) Set Uses

func (pdb *PrefixDB) Set(key []byte, value []byte) error

Set implements DB.

func (*PrefixDB) SetSync Uses

func (pdb *PrefixDB) SetSync(key []byte, value []byte) error

SetSync implements DB.

func (*PrefixDB) Stats Uses

func (pdb *PrefixDB) Stats() map[string]string

Stats implements DB.

Directories

PathSynopsis
remotedbremotedb is a package for connecting to distributed Tendermint db.DB instances.
remotedb/grpcdbgrpcdb is the distribution of Tendermint's db.DB instances using the gRPC transport to decouple local db.DB usages from applications, to using them over a network in a highly performant manner.
remotedb/proto

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