quantum

Documentation

Overview

Copyright 2022 Molecula Corp. (DBA FeatureBase). SPDX-License-Identifier: Apache-2.0

Index

• Constants
• Variables
• func MinMaxViews(views []string, q TimeQuantum) (min string, max string)
• func TimeOfView(v string, adj bool) (time.Time, error)
• func ViewByTimeUnit(name string, t time.Time, unit rune) string
• func ViewsByTime(name string, t time.Time, q TimeQuantum) []string
• func ViewsByTimeInto(fullBuf []byte, into [][]byte, t time.Time, q TimeQuantum) [][]byte
• func ViewsByTimeRange(name string, start, end time.Time, q TimeQuantum) []string
• type TimeQuantum
  • func (q TimeQuantum) Granularity() rune
  • func (q TimeQuantum) HasDay() bool
  • func (q TimeQuantum) HasHour() bool
  • func (q TimeQuantum) HasMonth() bool
  • func (q TimeQuantum) HasYear() bool
  • func (q TimeQuantum) IsEmpty() bool
  • func (q *TimeQuantum) Set(value string) error
  • func (q TimeQuantum) String() string
  • func (q TimeQuantum) Type() string
  • func (q TimeQuantum) Valid() bool

Constants

const TimeFormat = "2006-01-02T15:04"

Variables

var ErrInvalidTimeQuantum = errors.New("invalid time quantum")

ErrInvalidTimeQuantum is returned when parsing a time quantum.

Functions

func MinMaxViews

func MinMaxViews(views []string, q TimeQuantum) (min string, max string)

MinMaxViews returns the min and max view from a list of views with a time quantum taken into consideration. It assumes that all views represent the same base view name (the logic depends on the views sorting correctly in alphabetical order).

func TimeOfView

func TimeOfView(v string, adj bool) (time.Time, error)

TimeOfView returns a valid time.Time based on the view string. For upper bound use, the result can be adjusted by one by setting the `adj` argument to `true`.

func ViewByTimeUnit

func ViewByTimeUnit(name string, t time.Time, unit rune) string

ViewByTimeUnit returns the view name for time with a given quantum unit.

func ViewsByTime

func ViewsByTime(name string, t time.Time, q TimeQuantum) []string

ViewsByTime returns a list of views for a given timestamp.

func ViewsByTimeInto

func ViewsByTimeInto(fullBuf []byte, into [][]byte, t time.Time, q TimeQuantum) [][]byte

ViewsByTimeInto computes the list of views for a given time. It expects to be given an initial buffer of the form `name_YYYYMMDDHH`, and a slice of []bytes. This allows us to reuse the buffer for all the sub-buffers, and also to reuse the slice of slices, to eliminate all those allocations. This might seem crazy, but even including the JSON parsing and all the disk activity, the straightforward viewsByTime implementation was 25% of runtime in an ingest test.

func ViewsByTimeRange

func ViewsByTimeRange(name string, start, end time.Time, q TimeQuantum) []string

ViewsByTimeRange returns a list of views to traverse to query a time range.

Types

type TimeQuantum

type TimeQuantum string

TimeQuantum represents a time granularity for time-based bitmaps.

func (TimeQuantum) Granularity

func (q TimeQuantum) Granularity() rune

func (TimeQuantum) HasDay

func (q TimeQuantum) HasDay() bool

HasDay returns true if the quantum contains a 'D' unit.

func (TimeQuantum) HasHour

func (q TimeQuantum) HasHour() bool

HasHour returns true if the quantum contains a 'H' unit.

func (TimeQuantum) HasMonth

func (q TimeQuantum) HasMonth() bool

HasMonth returns true if the quantum contains a 'M' unit.

func (TimeQuantum) HasYear

func (q TimeQuantum) HasYear() bool

HasYear returns true if the quantum contains a 'Y' unit.

func (TimeQuantum) IsEmpty

func (q TimeQuantum) IsEmpty() bool

IsEmpty returns true if the quantum is empty.

func (*TimeQuantum) Set

func (q *TimeQuantum) Set(value string) error

Set sets the time quantum value.

func (TimeQuantum) String

func (q TimeQuantum) String() string

func (TimeQuantum) Type

func (q TimeQuantum) Type() string

Type returns the type of a time quantum value.

func (TimeQuantum) Valid

func (q TimeQuantum) Valid() bool

Valid returns true if q is a valid time quantum value.