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README
¶
DB
The db package contains the key-value database interface and memdb implementation. The memdb is a simple in-memory key-value store that is used for testing and development purposes.
Context
The main purpose of the db package is to provide decoupling between cosmos-db and iavl packages. It provides a simple wrapper for the old users of iavl and cosmos-db to use the new db package without changing their code. For example:
package main
import (
"cosmossdk.io/log"
dbm "github.com/cosmos/cosmos-db"
"github.com/cosmos/iavl"
idbm "github.com/cosmos/iavl/db"
)
func main() {
levelDB, err := dbm.NewDB("application", dbm.GoLevelDBBackend, "test")
if err != nil {
panic(err)
}
tree := iavl.NewMutableTree(idbm.NewWrapper(dbm.NewPrefixDB(levelDB, []byte("s/k:main/"))), 0, false, NewNopLogger())
}
Documentation
¶
Index ¶
- Constants
- func IteratePrefix(db DB, prefix []byte) (corestore.Iterator, error)
- type DB
- type GoLevelDB
- func (db *GoLevelDB) Close() error
- func (db *GoLevelDB) Delete(key []byte) error
- func (db *GoLevelDB) DeleteSync(key []byte) error
- func (db *GoLevelDB) ForceCompact(start, limit []byte) error
- func (db *GoLevelDB) Get(key []byte) ([]byte, error)
- func (db *GoLevelDB) Has(key []byte) (bool, error)
- func (db *GoLevelDB) Iterator(start, end []byte) (corestore.Iterator, error)
- func (db *GoLevelDB) NewBatch() corestore.Batch
- func (db *GoLevelDB) NewBatchWithSize(size int) corestore.Batch
- func (db *GoLevelDB) Print() error
- func (db *GoLevelDB) RawDB() *leveldb.DB
- func (db *GoLevelDB) ReverseIterator(start, end []byte) (corestore.Iterator, error)
- func (db *GoLevelDB) Set(key, value []byte) error
- func (db *GoLevelDB) SetSync(key, value []byte) error
- func (db *GoLevelDB) Stats() map[string]string
- type MemDB
- func (db *MemDB) Close() error
- func (db *MemDB) Delete(key []byte) error
- func (db *MemDB) DeleteSync(key []byte) error
- func (db *MemDB) Get(key []byte) ([]byte, error)
- func (db *MemDB) Has(key []byte) (bool, error)
- func (db *MemDB) Iterator(start, end []byte) (corestore.Iterator, error)
- func (db *MemDB) IteratorNoMtx(start, end []byte) (corestore.Iterator, error)
- func (db *MemDB) NewBatch() corestore.Batch
- func (db *MemDB) NewBatchWithSize(_ int) corestore.Batch
- func (db *MemDB) Print() error
- func (db *MemDB) ReverseIterator(start, end []byte) (corestore.Iterator, error)
- func (db *MemDB) ReverseIteratorNoMtx(start, end []byte) (corestore.Iterator, error)
- func (db *MemDB) Set(key []byte, value []byte) error
- func (db *MemDB) SetSync(key []byte, value []byte) error
- func (db *MemDB) Stats() map[string]string
- type PrefixDB
- func (pdb *PrefixDB) Close() error
- func (pdb *PrefixDB) Delete(key []byte) error
- func (pdb *PrefixDB) Get(key []byte) ([]byte, error)
- func (pdb *PrefixDB) Has(key []byte) (bool, error)
- func (pdb *PrefixDB) Iterator(start, end []byte) (corestore.Iterator, error)
- func (pdb *PrefixDB) NewBatch() corestore.Batch
- func (pdb *PrefixDB) NewBatchWithSize(size int) corestore.Batch
- func (pdb *PrefixDB) Print() error
- func (pdb *PrefixDB) ReverseIterator(start, end []byte) (corestore.Iterator, error)
- func (pdb *PrefixDB) Set(key, value []byte) error
Constants ¶
const DBFileSuffix string = ".db"
Variables ¶
This section is empty.
Functions ¶
Types ¶
type DB ¶
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)
// 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) (corestore.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) (corestore.Iterator, error)
// Close closes the database connection.
Close() error
// NewBatch creates a batch for atomic updates. The caller must call Batch.Close.
NewBatch() corestore.Batch
// NewBatchWithSize create a new batch for atomic updates, but with pre-allocated size.
// This will does the same thing as NewBatch if the batch implementation doesn't support pre-allocation.
NewBatchWithSize(int) corestore.Batch
}
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.
type GoLevelDB ¶ added in v1.3.0
type GoLevelDB struct {
// contains filtered or unexported fields
}
GoLevelDB implements corestore.KVStore using github.com/syndtr/goleveldb/leveldb. It is used for only store v2 migration, since some clients use goleveldb as the IAVL v0/v1 backend.
func NewGoLevelDB ¶ added in v1.3.0
func NewGoLevelDBWithOpts ¶ added in v1.3.0
func (*GoLevelDB) DeleteSync ¶ added in v1.3.0
DeleteSync implements corestore.KVStore.
func (*GoLevelDB) ForceCompact ¶ added in v1.3.0
func (*GoLevelDB) NewBatchWithSize ¶ added in v1.3.0
NewBatchWithSize implements corestore.BatchCreator.
func (*GoLevelDB) ReverseIterator ¶ added in v1.3.0
ReverseIterator implements corestore.KVStore.
type MemDB ¶
type MemDB struct {
// contains filtered or unexported fields
}
MemDB is an in-memory database backend using a B-tree for the test purpose.
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 (*MemDB) Iterator ¶
Iterator implements DB. Takes out a read-lock on the database until the iterator is closed.
func (*MemDB) IteratorNoMtx ¶
IteratorNoMtx makes an iterator with no mutex.
func (*MemDB) NewBatchWithSize ¶
NewBatchWithSize implements DB. It does the same thing as NewBatch because we can't pre-allocate memDBBatch
func (*MemDB) ReverseIterator ¶
ReverseIterator implements DB. Takes out a read-lock on the database until the iterator is closed.
func (*MemDB) ReverseIteratorNoMtx ¶
ReverseIteratorNoMtx makes an iterator with no mutex.
type PrefixDB ¶ added in v1.3.0
type PrefixDB struct {
// contains filtered or unexported fields
}
PrefixDB wraps a namespace of another database as a logical database.
func NewPrefixDB ¶ added in v1.3.0
func NewPrefixDB(db corestore.KVStoreWithBatch, prefix []byte) *PrefixDB
NewPrefixDB lets you namespace multiple corestore.KVStores within a single corestore.KVStore.
func (*PrefixDB) NewBatchWithSize ¶ added in v1.3.0
NewBatchWithSize implements corestore.BatchCreator.
func (*PrefixDB) ReverseIterator ¶ added in v1.3.0
ReverseIterator implements corestore.KVStore.
Source Files