revisions

package
v1.57.1 Latest Latest
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 Go to latest Published: Nov 10, 2026 License: Apache-2.0 Imports: 11 Imported by: 0

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Index

Constants

View Source 
const (
	// Timestamp is a revision that is a timestamp.
	Timestamp RevisionKind = "timestamp"

	// TransactionID is a revision that is a transaction ID.
	TransactionID = "txid"

	// HybridLogicalClock is a revision that is a hybrid logical clock.
	HybridLogicalClock = "hlc"
)

Variables

This section is empty.

Functions

func CheckGCWindow added in v1.57.0 

func CheckGCWindow(now, rev WithTimestampRevision, gcWindow time.Duration) error

CheckGCWindow verifies that the given revision is within the datastore's software GC window relative to the current time: not so old that it has (likely) been garbage collected, and not from the future.

func HLCKeyLessThanFunc 

func HLCKeyLessThanFunc(lhs, rhs HLCRevision) bool

HLCKeyLessThanFunc is used to compare keys created by the HLCKeyFunc.

func TimestampIDKeyFunc 

func TimestampIDKeyFunc(r TimestampRevision) int64

TimestampIDKeyFunc is used to create keys for timestamps.

func TimestampIDKeyLessThanFunc 

func TimestampIDKeyLessThanFunc(l, r int64) bool

TimestampIDKeyLessThanFunc is used to create keys for timestamps.

func TransactionIDKeyFunc 

func TransactionIDKeyFunc(r TransactionIDRevision) uint64

TransactionIDKeyFunc is used to create keys for transaction IDs.

func TransactionIDKeyLessThanFunc 

func TransactionIDKeyLessThanFunc(l, r uint64) bool

TransactionIDKeyLessThanFunc is used to create keys for transaction IDs.

Types

type CommonDecoder 

type CommonDecoder struct {
	Kind              RevisionKind
	DatastoreUniqueID string
}

CommonDecoder is a revision decoder that can decode revisions of a given kind.

func (CommonDecoder) RevisionFromString 

func (cd CommonDecoder) RevisionFromString(s string) (datastore.Revision, error)

func (CommonDecoder) UniqueID added in v1.46.0 

func (cd CommonDecoder) UniqueID(_ context.Context) (string, error)

type HLCRevision 

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

HLCRevision is a revision that is a hybrid logical clock, stored as two integers. The first integer is the timestamp in nanoseconds, and the second integer is the logical clock defined as 11 digits, with the first digit being ignored to ensure precision of the given logical clock.

func HLCKeyFunc 

func HLCKeyFunc(r HLCRevision) HLCRevision

HLCKeyFunc is used to convert a simple HLC for use in maps.

func HLCRevisionFromString 

func HLCRevisionFromString(revisionStr string) (HLCRevision, error)

HLCRevisionFromString parses a string into a hybrid logical clock revision.

func NewForHLC 

func NewForHLC(decimal decimal.Decimal) (HLCRevision, error)

NewForHLC creates a new revision for the given hybrid logical clock.

func NewHLCForTime 

func NewHLCForTime(time time.Time) HLCRevision

NewHLCForTime creates a new revision for the given time.

func (HLCRevision) AppendSortKey added in v1.57.0 

func (hlc HLCRevision) AppendSortKey(dst []byte) []byte

AppendSortKey implements datastore.SortKeyRevision. Keys are hlcSortKeyLength bytes.

func (HLCRevision) AsDecimal added in v1.34.0 

func (hlc HLCRevision) AsDecimal() (decimal.Decimal, error)

func (HLCRevision) ByteSortable added in v1.39.0 

func (hlc HLCRevision) ByteSortable() bool

func (HLCRevision) ConstructForTimestamp 

func (hlc HLCRevision) ConstructForTimestamp(timestamp int64) WithTimestampRevision

func (HLCRevision) Equal 

func (hlc HLCRevision) Equal(rhs datastore.Revision) bool

func (HLCRevision) GreaterThan 

func (hlc HLCRevision) GreaterThan(rhs datastore.Revision) bool

func (HLCRevision) InexactFloat64 

func (hlc HLCRevision) InexactFloat64() float64

func (HLCRevision) LessThan 

func (hlc HLCRevision) LessThan(rhs datastore.Revision) bool

func (HLCRevision) String 

func (hlc HLCRevision) String() string

func (HLCRevision) TimestampNanoSec 

func (hlc HLCRevision) TimestampNanoSec() int64

type ParsingFunc 

type ParsingFunc func(revisionStr string) (rev datastore.Revision, err error)

ParsingFunc is a function that can parse a string into a revision.

func RevisionParser 

func RevisionParser(kind RevisionKind) ParsingFunc

RevisionParser returns a ParsingFunc for the given RevisionKind.

type RevisionKind 

type RevisionKind string

RevisionKind is an enum of the different kinds of revisions that can be used.

type TimestampRevision 

type TimestampRevision int64

TimestampRevision is a revision that is a timestamp.

func NewForTime 

func NewForTime(time time.Time) TimestampRevision

NewForTime creates a new revision for the given time.

func NewForTimestamp 

func NewForTimestamp(timestampNanosec int64) TimestampRevision

NewForTimestamp creates a new revision for the given timestamp.

func (TimestampRevision) AppendSortKey added in v1.57.0 

func (ir TimestampRevision) AppendSortKey(dst []byte) []byte

AppendSortKey implements datastore.SortKeyRevision. Keys are timestampSortKeyLength bytes.

func (TimestampRevision) ByteSortable added in v1.39.0 

func (ir TimestampRevision) ByteSortable() bool

func (TimestampRevision) ConstructForTimestamp 

func (ir TimestampRevision) ConstructForTimestamp(timestamp int64) WithTimestampRevision

func (TimestampRevision) Equal 

func (ir TimestampRevision) Equal(rhs datastore.Revision) bool

func (TimestampRevision) GreaterThan 

func (ir TimestampRevision) GreaterThan(rhs datastore.Revision) bool

func (TimestampRevision) LessThan 

func (ir TimestampRevision) LessThan(rhs datastore.Revision) bool

func (TimestampRevision) String 

func (ir TimestampRevision) String() string

func (TimestampRevision) Time 

func (ir TimestampRevision) Time() time.Time

func (TimestampRevision) TimestampNanoSec 

func (ir TimestampRevision) TimestampNanoSec() int64

func (TimestampRevision) WithInexactFloat64 

func (ir TimestampRevision) WithInexactFloat64() float64

type TransactionIDRevision 

type TransactionIDRevision uint64

TransactionIDRevision is a revision that is a transaction ID.

func NewForTransactionID 

func NewForTransactionID(transactionID uint64) TransactionIDRevision

NewForTransactionID creates a new revision for the given transaction ID.

func (TransactionIDRevision) AppendSortKey added in v1.57.0 

func (ir TransactionIDRevision) AppendSortKey(dst []byte) []byte

AppendSortKey implements datastore.SortKeyRevision. Keys are transactionIDSortKeyLength bytes.

func (TransactionIDRevision) ByteSortable added in v1.39.0 

func (ir TransactionIDRevision) ByteSortable() bool

func (TransactionIDRevision) Equal 

func (ir TransactionIDRevision) Equal(rhs datastore.Revision) bool

func (TransactionIDRevision) GreaterThan 

func (ir TransactionIDRevision) GreaterThan(rhs datastore.Revision) bool

func (TransactionIDRevision) LessThan 

func (ir TransactionIDRevision) LessThan(rhs datastore.Revision) bool

func (TransactionIDRevision) String 

func (ir TransactionIDRevision) String() string

func (TransactionIDRevision) TransactionID 

func (ir TransactionIDRevision) TransactionID() uint64

func (TransactionIDRevision) WithInexactFloat64 

func (ir TransactionIDRevision) WithInexactFloat64() float64

type WithInexactFloat64 

type WithInexactFloat64 interface {
	// InexactFloat64 returns a float64 that is an inexact representation of the
	// revision.
	InexactFloat64() float64
}

WithInexactFloat64 is an interface that can be implemented by a revision to provide an inexact float64 representation of the revision.

type WithTimestampRevision 

type WithTimestampRevision interface {
	datastore.Revision
	TimestampNanoSec() int64
	ConstructForTimestamp(timestampNanoSec int64) WithTimestampRevision
}

WithTimestampRevision is an interface that can be implemented by a revision to provide a timestamp.

func Quantize added in v1.57.0 

func Quantize(now WithTimestampRevision, followerReadDelay, quantization time.Duration) (WithTimestampRevision, time.Duration)

Quantize rounds a timestamp-based "now" revision down to a quantization boundary, after subtracting the follower-read delay, and reports how long the result remains valid: until the next boundary. A zero quantization returns the delayed now unchanged with no validity.

This is the in-Go quantization used by datastores whose revision is a clock reading (CockroachDB, Spanner, memdb). Datastores that quantize in SQL (Postgres, MySQL) compute validFor in their query and do not use this helper.

Source Files

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