Documentation
¶
Index ¶
- Constants
- Variables
- type Batch
- type Batcher
- type Compacter
- type Database
- type Deleter
- type Iteratee
- type Iterator
- type KeyValueReader
- type KeyValueStore
- type KeyValueWriter
- type LDBDatabase
- func (db *LDBDatabase) Close()
- func (db *LDBDatabase) Delete(key []byte) error
- func (db *LDBDatabase) Get(key []byte) ([]byte, error)
- func (db *LDBDatabase) Has(key []byte) (bool, error)
- func (db *LDBDatabase) LDB() *leveldb.DB
- func (db *LDBDatabase) Meter(prefix string)
- func (db *LDBDatabase) NewBatch() Batch
- func (db *LDBDatabase) NewIterator() iterator.Iterator
- func (db *LDBDatabase) NewIteratorWithPrefix(prefix []byte) iterator.Iterator
- func (db *LDBDatabase) Path() string
- func (db *LDBDatabase) Put(key []byte, value []byte) error
- type MemDatabase
- func (db *MemDatabase) Close()
- func (db *MemDatabase) Delete(key []byte) error
- func (db *MemDatabase) Get(key []byte) ([]byte, error)
- func (db *MemDatabase) Has(key []byte) (bool, error)
- func (db *MemDatabase) Keys() [][]byte
- func (db *MemDatabase) Len() int
- func (db *MemDatabase) NewBatch() Batch
- func (db *MemDatabase) Put(key []byte, value []byte) error
- type Putter
- type Stater
Constants ¶
const IdealBatchSize = 100 * 1024
Code using batches should try to add this much data to the batch. The value was determined empirically.
Variables ¶
var OpenFileLimit = 64
Functions ¶
This section is empty.
Types ¶
type Batch ¶
type Batch interface {
Putter
Deleter
ValueSize() int // amount of data in the batch
Write() error
// Reset resets the batch for reuse
Reset()
}
Batch is a write-only database that commits changes to its host database when Write is called. Batch cannot be used concurrently.
func NewTableBatch ¶
NewTableBatch returns a Batch object which prefixes all keys with a given string.
type Batcher ¶
type Batcher interface {
// NewBatch creates a write-only database that buffers changes to its host db
// until a final write is called.
NewBatch() Batch
}
Batcher wraps the NewBatch method of a backing data store.
type Compacter ¶
type Compacter interface {
// Compact flattens the underlying data store for the given key range. In essence,
// deleted and overwritten versions are discarded, and the data is rearranged to
// reduce the cost of operations needed to access them.
//
// A nil start is treated as a key before all keys in the data store; a nil limit
// is treated as a key after all keys in the data store. If both is nil then it
// will compact entire data store.
Compact(start []byte, limit []byte) error
}
Compacter wraps the Compact method of a backing data store.
type Database ¶
type Database interface {
Putter
Deleter
Get(key []byte) ([]byte, error)
Has(key []byte) (bool, error)
Close()
NewBatch() Batch
}
Database wraps all database operations. All methods are safe for concurrent use.
type Deleter ¶
Deleter wraps the database delete operation supported by both batches and regular databases.
type Iteratee ¶
type Iteratee interface {
// NewIterator creates a binary-alphabetical iterator over the entire keyspace
// contained within the key-value database.
NewIterator() Iterator
// NewIteratorWithStart creates a binary-alphabetical iterator over a subset of
// database content starting at a particular initial key (or after, if it does
// not exist).
NewIteratorWithStart(start []byte) Iterator
// NewIteratorWithPrefix creates a binary-alphabetical iterator over a subset
// of database content with a particular key prefix.
NewIteratorWithPrefix(prefix []byte) Iterator
}
Iteratee wraps the NewIterator methods of a backing data store.
type Iterator ¶
type Iterator interface {
// Next moves the iterator to the next key/value pair. It returns whether the
// iterator is exhausted.
Next() bool
// Error returns any accumulated error. Exhausting all the key/value pairs
// is not considered to be an error.
Error() error
// Key returns the key of the current key/value pair, or nil if done. The caller
// should not modify the contents of the returned slice, and its contents may
// change on the next call to Next.
Key() []byte
// Value returns the value of the current key/value pair, or nil if done. The
// caller should not modify the contents of the returned slice, and its contents
// may change on the next call to Next.
Value() []byte
// Release releases associated resources. Release should always succeed and can
// be called multiple times without causing error.
Release()
}
Iterator iterates over a database's key/value pairs in ascending key order.
When it encounters an error any seek will return false and will yield no key/ value pairs. The error can be queried by calling the Error method. Calling Release is still necessary.
An iterator must be released after use, but it is not necessary to read an iterator until exhaustion. An iterator is not safe for concurrent use, but it is safe to use multiple iterators concurrently.
type KeyValueReader ¶
type KeyValueReader interface {
// Has retrieves if a key is present in the key-value data store.
Has(key []byte) (bool, error)
// Get retrieves the given key if it's present in the key-value data store.
Get(key []byte) ([]byte, error)
}
KeyValueReader wraps the Has and Get method of a backing data store.
type KeyValueStore ¶
type KeyValueStore interface {
KeyValueReader
KeyValueWriter
Batcher
Iteratee
Stater
Compacter
io.Closer
}
KeyValueStore contains all the methods required to allow handling different key-value data stores backing the high level database.
type KeyValueWriter ¶
type KeyValueWriter interface {
// Put inserts the given value into the key-value data store.
Put(key []byte, value []byte) error
// Delete removes the key from the key-value data store.
Delete(key []byte) error
}
KeyValueWriter wraps the Put method of a backing data store.
type LDBDatabase ¶
type LDBDatabase struct {
// contains filtered or unexported fields
}
func NewLDBDatabase ¶
func NewLDBDatabase(file string, cache int, handles int) (*LDBDatabase, error)
NewLDBDatabase returns a LevelDB wrapped object.
func (*LDBDatabase) Close ¶
func (db *LDBDatabase) Close()
func (*LDBDatabase) Delete ¶
func (db *LDBDatabase) Delete(key []byte) error
Delete deletes the key from the queue and database
func (*LDBDatabase) Get ¶
func (db *LDBDatabase) Get(key []byte) ([]byte, error)
Get returns the given key if it's present.
func (*LDBDatabase) LDB ¶
func (db *LDBDatabase) LDB() *leveldb.DB
func (*LDBDatabase) Meter ¶
func (db *LDBDatabase) Meter(prefix string)
Meter configures the database metrics collectors and
func (*LDBDatabase) NewBatch ¶
func (db *LDBDatabase) NewBatch() Batch
func (*LDBDatabase) NewIterator ¶
func (db *LDBDatabase) NewIterator() iterator.Iterator
func (*LDBDatabase) NewIteratorWithPrefix ¶
func (db *LDBDatabase) NewIteratorWithPrefix(prefix []byte) iterator.Iterator
NewIteratorWithPrefix returns a iterator to iterate over subset of database content with a particular prefix.
func (*LDBDatabase) Path ¶
func (db *LDBDatabase) Path() string
Path returns the path to the database directory.
type MemDatabase ¶
type MemDatabase struct {
// contains filtered or unexported fields
}
* This is a test memory database. Do not use for any production it does not get persisted
func NewMemDatabase ¶
func NewMemDatabase() *MemDatabase
func NewMemDatabaseWithCap ¶
func NewMemDatabaseWithCap(size int) *MemDatabase
func (*MemDatabase) Close ¶
func (db *MemDatabase) Close()
func (*MemDatabase) Delete ¶
func (db *MemDatabase) Delete(key []byte) error
func (*MemDatabase) Keys ¶
func (db *MemDatabase) Keys() [][]byte
func (*MemDatabase) Len ¶
func (db *MemDatabase) Len() int
func (*MemDatabase) NewBatch ¶
func (db *MemDatabase) NewBatch() Batch
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