database

Documentation

Index

• Constants
• Variables
• func GetID(db KeyValueReader, key []byte) (ids.ID, error)
• func GetTimestamp(db KeyValueReader, key []byte) (time.Time, error)
• func GetUInt32(db KeyValueReader, key []byte) (uint32, error)
• func GetUInt64(db KeyValueReader, key []byte) (uint64, error)
• func PackUInt32(val uint32) []byte
• func PackUInt64(val uint64) []byte
• func ParseID(b []byte) (ids.ID, error)
• func ParseTimestamp(b []byte) (time.Time, error)
• func ParseUInt32(b []byte) (uint32, error)
• func ParseUInt64(b []byte) (uint64, error)
• func PutID(db KeyValueWriter, key []byte, val ids.ID) error
• func PutTimestamp(db KeyValueWriter, key []byte, val time.Time) error
• func PutUInt32(db KeyValueWriter, key []byte, val uint32) error
• func PutUInt64(db KeyValueWriter, key []byte, val uint64) error
• func Size(db Iteratee) (int, error)
• func TestBatchDelete(t *testing.T, db Database)
• func TestBatchInner(t *testing.T, db Database)
• func TestBatchLargeSize(t *testing.T, db Database)
• func TestBatchPut(t *testing.T, db Database)
• func TestBatchReplay(t *testing.T, db Database)
• func TestBatchReset(t *testing.T, db Database)
• func TestBatchReuse(t *testing.T, db Database)
• func TestBatchRewrite(t *testing.T, db Database)
• func TestCompactNoPanic(t *testing.T, db Database)
• func TestIterator(t *testing.T, db Database)
• func TestIteratorClosed(t *testing.T, db Database)
• func TestIteratorError(t *testing.T, db Database)
• func TestIteratorErrorAfterRelease(t *testing.T, db Database)
• func TestIteratorMemorySafety(t *testing.T, db Database)
• func TestIteratorPrefix(t *testing.T, db Database)
• func TestIteratorStart(t *testing.T, db Database)
• func TestIteratorStartPrefix(t *testing.T, db Database)
• func TestMemorySafetyBatch(t *testing.T, db Database)
• func TestMemorySafetyDatabase(t *testing.T, db Database)
• func TestSimpleKeyValue(t *testing.T, db Database)
• func TestSimpleKeyValueClosed(t *testing.T, db Database)
• func TestStatNoPanic(t *testing.T, db Database)
• type Batch
• type Batcher
• type Compacter
• type Database
• type Iteratee
• type Iterator
• type KeyValueReader
• type KeyValueWriter
• type Stater

Constants

const (
	// MaxExcessCapacityFactor ...
	// If, when a batch is reset, the cap(batch)/len(batch) > MaxExcessCapacityFactor,
	// the underlying array's capacity will be reduced by a factor of capacityReductionFactor.
	// Higher value for MaxExcessCapacityFactor --> less aggressive array downsizing --> less memory allocations
	// but more unnecessary data in the underlying array that can't be garbage collected.
	// Higher value for CapacityReductionFactor --> more aggressive array downsizing --> more memory allocations
	// but less unnecessary data in the underlying array that can't be garbage collected.
	MaxExcessCapacityFactor = 4
	// CapacityReductionFactor ...
	CapacityReductionFactor = 2
)

Variables

var (
	ErrClosed          = errors.New("closed")
	ErrNotFound        = errors.New("not found")
	ErrAvoidCorruption = errors.New("closed to avoid possible corruption")
)

common errors

var Tests = []func(t *testing.T, db Database){
	TestSimpleKeyValue,
	TestSimpleKeyValueClosed,
	TestBatchPut,
	TestBatchDelete,
	TestBatchReset,
	TestBatchReuse,
	TestBatchRewrite,
	TestBatchReplay,
	TestBatchInner,
	TestBatchLargeSize,
	TestIterator,
	TestIteratorStart,
	TestIteratorPrefix,
	TestIteratorStartPrefix,
	TestIteratorMemorySafety,
	TestIteratorClosed,
	TestIteratorError,
	TestIteratorErrorAfterRelease,
	TestStatNoPanic,
	TestCompactNoPanic,
	TestMemorySafetyDatabase,
	TestMemorySafetyBatch,
}

Tests is a list of all database tests

Functions

func GetID

func GetID(db KeyValueReader, key []byte) (ids.ID, error)

func GetTimestamp

func GetTimestamp(db KeyValueReader, key []byte) (time.Time, error)

func GetUInt32

func GetUInt32(db KeyValueReader, key []byte) (uint32, error)

func GetUInt64

func GetUInt64(db KeyValueReader, key []byte) (uint64, error)

func PackUInt32

func PackUInt32(val uint32) []byte

func PackUInt64

func PackUInt64(val uint64) []byte

func ParseID

func ParseID(b []byte) (ids.ID, error)

func ParseTimestamp

func ParseTimestamp(b []byte) (time.Time, error)

func ParseUInt32

func ParseUInt32(b []byte) (uint32, error)

func ParseUInt64

func ParseUInt64(b []byte) (uint64, error)

func PutID

func PutID(db KeyValueWriter, key []byte, val ids.ID) error

func PutTimestamp

func PutTimestamp(db KeyValueWriter, key []byte, val time.Time) error

func PutUInt32

func PutUInt32(db KeyValueWriter, key []byte, val uint32) error

func PutUInt64

func PutUInt64(db KeyValueWriter, key []byte, val uint64) error

func Size

func Size(db Iteratee) (int, error)

func TestBatchDelete

func TestBatchDelete(t *testing.T, db Database)

TestBatchDelete tests to make sure that batched deletes work as expected.

func TestBatchInner

func TestBatchInner(t *testing.T, db Database)

TestBatchInner tests to make sure that inner can be used to write to the database.

func TestBatchLargeSize

func TestBatchLargeSize(t *testing.T, db Database)

TestBatchLargeSize tests to make sure that the batch can support a large amount of entries.

func TestBatchPut

func TestBatchPut(t *testing.T, db Database)

TestBatchPut tests to make sure that batched writes work as expected.

func TestBatchReplay

func TestBatchReplay(t *testing.T, db Database)

TestBatchReplay tests to make sure that batches will correctly replay their contents.

func TestBatchReset

func TestBatchReset(t *testing.T, db Database)

TestBatchReset tests to make sure that a batch drops un-written operations when it is reset.

func TestBatchReuse

func TestBatchReuse(t *testing.T, db Database)

TestBatchReuse tests to make sure that a batch can be reused once it is reset.

func TestBatchRewrite

func TestBatchRewrite(t *testing.T, db Database)

TestBatchRewrite tests to make sure that write can be called multiple times on a batch and the values will be updated correctly.

func TestCompactNoPanic

func TestCompactNoPanic(t *testing.T, db Database)

TestCompactNoPanic tests to make sure compact never panics.

func TestIterator

func TestIterator(t *testing.T, db Database)

TestIterator tests to make sure the database iterates over the database contents lexicographically.

func TestIteratorClosed

func TestIteratorClosed(t *testing.T, db Database)

TestIteratorClosed tests to make sure that an iterator that was created with a closed database will report a closed error correctly.

func TestIteratorError

func TestIteratorError(t *testing.T, db Database)

TestIteratorError tests to make sure that an iterator still works after the database is closed.

func TestIteratorErrorAfterRelease

func TestIteratorErrorAfterRelease(t *testing.T, db Database)

TestIteratorErrorAfterRelease tests to make sure that an iterator that was released still reports the error correctly.

func TestIteratorMemorySafety

func TestIteratorMemorySafety(t *testing.T, db Database)

TestIteratorMemorySafety tests to make sure that keys can values are able to be modified from the returned iterator.

func TestIteratorPrefix

func TestIteratorPrefix(t *testing.T, db Database)

TestIteratorPrefix tests to make sure the iterator can be configured to skip keys missing the provided prefix.

func TestIteratorStart

func TestIteratorStart(t *testing.T, db Database)

TestIteratorStart tests to make sure the the iterator can be configured to start mid way through the database.

func TestIteratorStartPrefix

func TestIteratorStartPrefix(t *testing.T, db Database)

TestIteratorStartPrefix tests to make sure that the iterator can start mid way through the database while skipping a prefix.

func TestMemorySafetyBatch

func TestMemorySafetyBatch(t *testing.T, db Database)

TestMemorySafetyDatabase ensures it is safe to modify a key after passing it to Batch.Put.

func TestMemorySafetyDatabase

func TestMemorySafetyDatabase(t *testing.T, db Database)

TestMemorySafetyDatabase ensures it is safe to modify a key after passing it to Database.Put and Database.Get.

func TestSimpleKeyValue

func TestSimpleKeyValue(t *testing.T, db Database)

TestSimpleKeyValue tests to make sure that simple Put + Get + Delete + Has calls return the expected values.

func TestSimpleKeyValueClosed

func TestSimpleKeyValueClosed(t *testing.T, db Database)

TestSimpleKeyValueClosed tests to make sure that Put + Get + Delete + Has calls return the correct error when the database has been closed.

func TestStatNoPanic

func TestStatNoPanic(t *testing.T, db Database)

TestStatNoPanic tests to make sure that Stat never panics.

Types

type Batch

type Batch interface {
	KeyValueWriter

	// Size retrieves the amount of data queued up for writing, this includes
	// the keys, values, and deleted keys.
	Size() int

	// Write flushes any accumulated data to disk.
	Write() error

	// Reset resets the batch for reuse.
	Reset()

	// Replay replays the batch contents.
	Replay(w KeyValueWriter) error

	// Inner returns a Batch writing to the inner database, if one exists. If
	// this batch is already writing to the base DB, then itself should be
	// returned.
	Inner() Batch
}

Batch is a write-only database that commits changes to its host database when Write is called. A batch cannot be used concurrently.

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 the underlying DB for the given key range.
	// Specifically, deleted and overwritten versions are discarded,
	// and the data is rearranged to reduce the cost of operations
	// needed to access the data. This operation should typically only
	// be invoked by users who understand the underlying implementation.
	//
	// A nil start is treated as a key before all keys in the DB.
	// And a nil limit is treated as a key after all keys in the DB.
	// Therefore if both are nil then it will compact entire DB.
	Compact(start []byte, limit []byte) error
}

Compacter wraps the Compact method of a backing data store.

type Database

type Database interface {
	KeyValueReader
	KeyValueWriter
	Batcher
	Iteratee
	Stater
	Compacter
	io.Closer
}

Database contains all the methods required to allow handling different key-value data stores backing the database.

type Iteratee

type Iteratee interface {
	// NewIterator creates an iterator over the entire keyspace contained within
	// the key-value database.
	NewIterator() Iterator

	// NewIteratorWithStart creates an iterator over a subset of database
	// content starting at a particular initial key.
	NewIteratorWithStart(start []byte) Iterator

	// NewIteratorWithPrefix creates an iterator over a subset of database
	// content with a particular key prefix.
	NewIteratorWithPrefix(prefix []byte) Iterator

	// NewIteratorWithStartAndPrefix creates an iterator over a subset of
	// database content with a particular key prefix starting at a specified
	// key.
	NewIteratorWithStartAndPrefix(start, 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 successfully moved to a new key/value pair.
	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.
	Key() []byte

	// Value returns the value of the current key/value pair, or nil if done.
	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.

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 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 Stater

type Stater interface {
	// Stat returns a particular internal stat of the database.
	Stat(property string) (string, error)
}

Stater wraps the Stat method of a backing data store.