histograms: General readability tweaks

- Adjust doc comments to go1.19 style.
- Break down some overly long lines.
- Minor doc comment tweaks and fixes.
- Some renaming.

Some rationales for the last point:

I have renamed “interjections” into “inserts”, mostly because it is
shorter, and the word shows up a lot by now (and the concept is
cryptic enough to not obfuscate it even more with abbreviations).

I have also tried to find more descriptive naming for the “compare
spans” functions.

Signed-off-by: beorn7 <beorn@grafana.com>
This commit is contained in:
beorn7 2023-01-18 13:47:22 +01:00
parent 9f91215bf6
commit 57c18420ab
7 changed files with 218 additions and 212 deletions

View file

@ -217,10 +217,10 @@ func (a *FloatHistogramAppender) AppendHistogram(int64, *histogram.Histogram) {
panic("appended an integer histogram to a float histogram chunk")
}
// Appendable returns whether the chunk can be appended to, and if so
// whether any recoding needs to happen using the provided interjections
// (in case of any new buckets, positive or negative range, respectively).
// If the sample is a gauge histogram, AppendableGauge must be used instead.
// Appendable returns whether the chunk can be appended to, and if so whether
// any recoding needs to happen using the provided inserts (in case of any new
// buckets, positive or negative range, respectively). If the sample is a gauge
// histogram, AppendableGauge must be used instead.
//
// The chunk is not appendable in the following cases:
// - The schema has changed.
@ -233,7 +233,7 @@ func (a *FloatHistogramAppender) AppendHistogram(int64, *histogram.Histogram) {
// because of a counter reset. If the given sample is stale, it is always ok to
// append. If counterReset is true, okToAppend is always false.
func (a *FloatHistogramAppender) Appendable(h *histogram.FloatHistogram) (
positiveInterjections, negativeInterjections []Interjection,
positiveInserts, negativeInserts []Insert,
okToAppend, counterReset bool,
) {
if a.NumSamples() > 0 && a.GetCounterResetHeader() == GaugeType {
@ -267,12 +267,12 @@ func (a *FloatHistogramAppender) Appendable(h *histogram.FloatHistogram) (
}
var ok bool
positiveInterjections, ok = forwardCompareSpans(a.pSpans, h.PositiveSpans)
positiveInserts, ok = expandSpansForward(a.pSpans, h.PositiveSpans)
if !ok {
counterReset = true
return
}
negativeInterjections, ok = forwardCompareSpans(a.nSpans, h.NegativeSpans)
negativeInserts, ok = expandSpansForward(a.nSpans, h.NegativeSpans)
if !ok {
counterReset = true
return
@ -280,7 +280,7 @@ func (a *FloatHistogramAppender) Appendable(h *histogram.FloatHistogram) (
if counterResetInAnyFloatBucket(a.pBuckets, h.PositiveBuckets, a.pSpans, h.PositiveSpans) ||
counterResetInAnyFloatBucket(a.nBuckets, h.NegativeBuckets, a.nSpans, h.NegativeSpans) {
counterReset, positiveInterjections, negativeInterjections = true, nil, nil
counterReset, positiveInserts, negativeInserts = true, nil, nil
return
}
@ -290,10 +290,11 @@ func (a *FloatHistogramAppender) Appendable(h *histogram.FloatHistogram) (
// AppendableGauge returns whether the chunk can be appended to, and if so
// whether:
// 1. Any recoding needs to happen to the chunk using the provided interjections
// 1. Any recoding needs to happen to the chunk using the provided inserts
// (in case of any new buckets, positive or negative range, respectively).
// 2. Any recoding needs to happen for the histogram being appended, using the backward interjections
// (in case of any missing buckets, positive or negative range, respectively).
// 2. Any recoding needs to happen for the histogram being appended, using the
// backward inserts (in case of any missing buckets, positive or negative
// range, respectively).
//
// This method must be only used for gauge histograms.
//
@ -302,8 +303,8 @@ func (a *FloatHistogramAppender) Appendable(h *histogram.FloatHistogram) (
// - The threshold for the zero bucket has changed.
// - The last sample in the chunk was stale while the current sample is not stale.
func (a *FloatHistogramAppender) AppendableGauge(h *histogram.FloatHistogram) (
positiveInterjections, negativeInterjections []Interjection,
backwardPositiveInterjections, backwardNegativeInterjections []Interjection,
positiveInserts, negativeInserts []Insert,
backwardPositiveInserts, backwardNegativeInserts []Insert,
positiveSpans, negativeSpans []histogram.Span,
okToAppend bool,
) {
@ -325,8 +326,8 @@ func (a *FloatHistogramAppender) AppendableGauge(h *histogram.FloatHistogram) (
return
}
positiveInterjections, backwardPositiveInterjections, positiveSpans = bidirectionalCompareSpans(a.pSpans, h.PositiveSpans)
negativeInterjections, backwardNegativeInterjections, negativeSpans = bidirectionalCompareSpans(a.nSpans, h.NegativeSpans)
positiveInserts, backwardPositiveInserts, positiveSpans = expandSpansBothWays(a.pSpans, h.PositiveSpans)
negativeInserts, backwardNegativeInserts, negativeSpans = expandSpansBothWays(a.nSpans, h.NegativeSpans)
okToAppend = true
return
}
@ -501,12 +502,12 @@ func (a *FloatHistogramAppender) writeXorValue(old *xorValue, v float64) {
}
// Recode converts the current chunk to accommodate an expansion of the set of
// (positive and/or negative) buckets used, according to the provided
// interjections, resulting in the honoring of the provided new positive and
// negative spans. To continue appending, use the returned Appender rather than
// the receiver of this method.
// (positive and/or negative) buckets used, according to the provided inserts,
// resulting in the honoring of the provided new positive and negative spans. To
// continue appending, use the returned Appender rather than the receiver of
// this method.
func (a *FloatHistogramAppender) Recode(
positiveInterjections, negativeInterjections []Interjection,
positiveInserts, negativeInserts []Insert,
positiveSpans, negativeSpans []histogram.Span,
) (Chunk, Appender) {
// TODO(beorn7): This currently just decodes everything and then encodes
@ -539,11 +540,11 @@ func (a *FloatHistogramAppender) Recode(
// Save the modified histogram to the new chunk.
hOld.PositiveSpans, hOld.NegativeSpans = positiveSpans, negativeSpans
if len(positiveInterjections) > 0 {
hOld.PositiveBuckets = interject(hOld.PositiveBuckets, positiveBuckets, positiveInterjections, false)
if len(positiveInserts) > 0 {
hOld.PositiveBuckets = insert(hOld.PositiveBuckets, positiveBuckets, positiveInserts, false)
}
if len(negativeInterjections) > 0 {
hOld.NegativeBuckets = interject(hOld.NegativeBuckets, negativeBuckets, negativeInterjections, false)
if len(negativeInserts) > 0 {
hOld.NegativeBuckets = insert(hOld.NegativeBuckets, negativeBuckets, negativeInserts, false)
}
app.AppendFloatHistogram(tOld, hOld)
}
@ -556,15 +557,15 @@ func (a *FloatHistogramAppender) Recode(
// (positive and/or negative) buckets used.
func (a *FloatHistogramAppender) RecodeHistogramm(
fh *histogram.FloatHistogram,
pBackwardInter, nBackwardInter []Interjection,
pBackwardInter, nBackwardInter []Insert,
) {
if len(pBackwardInter) > 0 {
numPositiveBuckets := countSpans(fh.PositiveSpans)
fh.PositiveBuckets = interject(fh.PositiveBuckets, make([]float64, numPositiveBuckets), pBackwardInter, false)
fh.PositiveBuckets = insert(fh.PositiveBuckets, make([]float64, numPositiveBuckets), pBackwardInter, false)
}
if len(nBackwardInter) > 0 {
numNegativeBuckets := countSpans(fh.NegativeSpans)
fh.NegativeBuckets = interject(fh.NegativeBuckets, make([]float64, numNegativeBuckets), nBackwardInter, false)
fh.NegativeBuckets = insert(fh.NegativeBuckets, make([]float64, numNegativeBuckets), nBackwardInter, false)
}
}

View file

@ -138,7 +138,7 @@ func TestFloatHistogramChunkSameBuckets(t *testing.T) {
require.Equal(t, ValNone, it4.Seek(exp[len(exp)-1].t+1))
}
// Mimics the scenario described for compareSpans().
// Mimics the scenario described for expandSpansForward.
func TestFloatHistogramChunkBucketChanges(t *testing.T) {
c := Chunk(NewFloatHistogramChunk())

View file

@ -243,10 +243,10 @@ func (a *HistogramAppender) AppendFloatHistogram(int64, *histogram.FloatHistogra
panic("appended a float histogram to a histogram chunk")
}
// Appendable returns whether the chunk can be appended to, and if so
// whether any recoding needs to happen using the provided interjections
// (in case of any new buckets, positive or negative range, respectively).
// If the sample is a gauge histogram, AppendableGauge must be used instead.
// Appendable returns whether the chunk can be appended to, and if so whether
// any recoding needs to happen using the provided inserts (in case of any new
// buckets, positive or negative range, respectively). If the sample is a gauge
// histogram, AppendableGauge must be used instead.
//
// The chunk is not appendable in the following cases:
//
@ -261,7 +261,7 @@ func (a *HistogramAppender) AppendFloatHistogram(int64, *histogram.FloatHistogra
// because of a counter reset. If the given sample is stale, it is always ok to
// append. If counterReset is true, okToAppend is always false.
func (a *HistogramAppender) Appendable(h *histogram.Histogram) (
positiveInterjections, negativeInterjections []Interjection,
positiveInserts, negativeInserts []Insert,
okToAppend, counterReset bool,
) {
if a.NumSamples() > 0 && a.GetCounterResetHeader() == GaugeType {
@ -295,12 +295,12 @@ func (a *HistogramAppender) Appendable(h *histogram.Histogram) (
}
var ok bool
positiveInterjections, ok = forwardCompareSpans(a.pSpans, h.PositiveSpans)
positiveInserts, ok = expandSpansForward(a.pSpans, h.PositiveSpans)
if !ok {
counterReset = true
return
}
negativeInterjections, ok = forwardCompareSpans(a.nSpans, h.NegativeSpans)
negativeInserts, ok = expandSpansForward(a.nSpans, h.NegativeSpans)
if !ok {
counterReset = true
return
@ -308,7 +308,7 @@ func (a *HistogramAppender) Appendable(h *histogram.Histogram) (
if counterResetInAnyBucket(a.pBuckets, h.PositiveBuckets, a.pSpans, h.PositiveSpans) ||
counterResetInAnyBucket(a.nBuckets, h.NegativeBuckets, a.nSpans, h.NegativeSpans) {
counterReset, positiveInterjections, negativeInterjections = true, nil, nil
counterReset, positiveInserts, negativeInserts = true, nil, nil
return
}
@ -318,10 +318,11 @@ func (a *HistogramAppender) Appendable(h *histogram.Histogram) (
// AppendableGauge returns whether the chunk can be appended to, and if so
// whether:
// 1. Any recoding needs to happen to the chunk using the provided interjections
// 1. Any recoding needs to happen to the chunk using the provided inserts
// (in case of any new buckets, positive or negative range, respectively).
// 2. Any recoding needs to happen for the histogram being appended, using the backward interjections
// (in case of any missing buckets, positive or negative range, respectively).
// 2. Any recoding needs to happen for the histogram being appended, using the
// backward inserts (in case of any missing buckets, positive or negative
// range, respectively).
//
// This method must be only used for gauge histograms.
//
@ -330,8 +331,8 @@ func (a *HistogramAppender) Appendable(h *histogram.Histogram) (
// - The threshold for the zero bucket has changed.
// - The last sample in the chunk was stale while the current sample is not stale.
func (a *HistogramAppender) AppendableGauge(h *histogram.Histogram) (
positiveInterjections, negativeInterjections []Interjection,
backwardPositiveInterjections, backwardNegativeInterjections []Interjection,
positiveInserts, negativeInserts []Insert,
backwardPositiveInserts, backwardNegativeInserts []Insert,
positiveSpans, negativeSpans []histogram.Span,
okToAppend bool,
) {
@ -353,8 +354,8 @@ func (a *HistogramAppender) AppendableGauge(h *histogram.Histogram) (
return
}
positiveInterjections, backwardPositiveInterjections, positiveSpans = bidirectionalCompareSpans(a.pSpans, h.PositiveSpans)
negativeInterjections, backwardNegativeInterjections, negativeSpans = bidirectionalCompareSpans(a.nSpans, h.NegativeSpans)
positiveInserts, backwardPositiveInserts, positiveSpans = expandSpansBothWays(a.pSpans, h.PositiveSpans)
negativeInserts, backwardNegativeInserts, negativeSpans = expandSpansBothWays(a.nSpans, h.NegativeSpans)
okToAppend = true
return
}
@ -488,8 +489,9 @@ func (a *HistogramAppender) AppendHistogram(t int64, h *histogram.Histogram) {
putVarbitInt(a.b, b)
}
} else {
// The case for the 2nd sample with single deltas is implicitly handled correctly with the double delta code,
// so we don't need a separate single delta logic for the 2nd sample.
// The case for the 2nd sample with single deltas is implicitly
// handled correctly with the double delta code, so we don't
// need a separate single delta logic for the 2nd sample.
tDelta = t - a.t
cntDelta = int64(h.Count) - int64(a.cnt)
@ -539,12 +541,12 @@ func (a *HistogramAppender) AppendHistogram(t int64, h *histogram.Histogram) {
}
// Recode converts the current chunk to accommodate an expansion of the set of
// (positive and/or negative) buckets used, according to the provided
// interjections, resulting in the honoring of the provided new positive and
// negative spans. To continue appending, use the returned Appender rather than
// the receiver of this method.
// (positive and/or negative) buckets used, according to the provided inserts,
// resulting in the honoring of the provided new positive and negative spans. To
// continue appending, use the returned Appender rather than the receiver of
// this method.
func (a *HistogramAppender) Recode(
positiveInterjections, negativeInterjections []Interjection,
positiveInserts, negativeInserts []Insert,
positiveSpans, negativeSpans []histogram.Span,
) (Chunk, Appender) {
// TODO(beorn7): This currently just decodes everything and then encodes
@ -577,11 +579,11 @@ func (a *HistogramAppender) Recode(
// Save the modified histogram to the new chunk.
hOld.PositiveSpans, hOld.NegativeSpans = positiveSpans, negativeSpans
if len(positiveInterjections) > 0 {
hOld.PositiveBuckets = interject(hOld.PositiveBuckets, positiveBuckets, positiveInterjections, true)
if len(positiveInserts) > 0 {
hOld.PositiveBuckets = insert(hOld.PositiveBuckets, positiveBuckets, positiveInserts, true)
}
if len(negativeInterjections) > 0 {
hOld.NegativeBuckets = interject(hOld.NegativeBuckets, negativeBuckets, negativeInterjections, true)
if len(negativeInserts) > 0 {
hOld.NegativeBuckets = insert(hOld.NegativeBuckets, negativeBuckets, negativeInserts, true)
}
app.AppendHistogram(tOld, hOld)
}
@ -590,19 +592,19 @@ func (a *HistogramAppender) Recode(
return hc, app
}
// RecodeHistogram converts the current histogram (in-place) to accommodate an expansion of the set of
// (positive and/or negative) buckets used.
// RecodeHistogram converts the current histogram (in-place) to accommodate an
// expansion of the set of (positive and/or negative) buckets used.
func (a *HistogramAppender) RecodeHistogram(
h *histogram.Histogram,
pBackwardInter, nBackwardInter []Interjection,
pBackwardInserts, nBackwardInserts []Insert,
) {
if len(pBackwardInter) > 0 {
if len(pBackwardInserts) > 0 {
numPositiveBuckets := countSpans(h.PositiveSpans)
h.PositiveBuckets = interject(h.PositiveBuckets, make([]int64, numPositiveBuckets), pBackwardInter, true)
h.PositiveBuckets = insert(h.PositiveBuckets, make([]int64, numPositiveBuckets), pBackwardInserts, true)
}
if len(nBackwardInter) > 0 {
if len(nBackwardInserts) > 0 {
numNegativeBuckets := countSpans(h.NegativeSpans)
h.NegativeBuckets = interject(h.NegativeBuckets, make([]int64, numNegativeBuckets), nBackwardInter, true)
h.NegativeBuckets = insert(h.NegativeBuckets, make([]int64, numNegativeBuckets), nBackwardInserts, true)
}
}

View file

@ -19,7 +19,10 @@ import (
"github.com/prometheus/prometheus/model/histogram"
)
func writeHistogramChunkLayout(b *bstream, schema int32, zeroThreshold float64, positiveSpans, negativeSpans []histogram.Span) {
func writeHistogramChunkLayout(
b *bstream, schema int32, zeroThreshold float64,
positiveSpans, negativeSpans []histogram.Span,
) {
putZeroThreshold(b, zeroThreshold)
putVarbitInt(b, int64(schema))
putHistogramChunkLayoutSpans(b, positiveSpans)
@ -91,9 +94,7 @@ func readHistogramChunkLayoutSpans(b *bstreamReader) ([]histogram.Span, error) {
// putZeroThreshold writes the zero threshold to the bstream. It stores typical
// values in just one byte, but needs 9 bytes for other values. In detail:
//
// * If the threshold is 0, store a single zero byte.
//
// - If the threshold is 0, store a single zero byte.
// - If the threshold is a power of 2 between (and including) 2^-243 and 2^10,
// take the exponent from the IEEE 754 representation of the threshold, which
// covers a range between (and including) -242 and 11. (2^-243 is 0.5*2^-242
@ -103,7 +104,6 @@ func readHistogramChunkLayoutSpans(b *bstreamReader) ([]histogram.Span, error) {
// threshold. The default value for the zero threshold is 2^-128 (or
// 0.5*2^-127 in IEEE 754 representation) and will therefore be encoded as a
// single byte (with value 116).
//
// - In all other cases, store 255 as a single byte, followed by the 8 bytes of
// the threshold as a float64, i.e. taking 9 bytes in total.
func putZeroThreshold(b *bstream, threshold float64) {
@ -186,16 +186,16 @@ func (b *bucketIterator) Next() (int, bool) {
return 0, false
}
// An Interjection describes how many new buckets have to be introduced before
// processing the pos'th delta from the original slice.
type Interjection struct {
// An Insert describes how many new buckets have to be inserted before
// processing the pos'th bucket from the original slice.
type Insert struct {
pos int
num int
}
// forwardCompareSpans returns the interjections to convert a slice of deltas to a new
// slice representing an expanded set of buckets, or false if incompatible
// (e.g. if buckets were removed).
// expandSpansForward returns the inserts to expand the bucket spans 'a' so that
// they match the spans in 'b'. 'b' must cover the same or more buckets than
// 'a', otherwise the function will return false.
//
// Example:
//
@ -222,25 +222,25 @@ type Interjection struct {
// deltas 6 -3 -3 3 -3 0 2 2 1 -5 1
// delta mods: / \ / \ / \
//
// Note that whenever any new buckets are introduced, the subsequent "old"
// bucket needs to readjust its delta to the new base of 0. Thus, for the caller
// who wants to transform the set of original deltas to a new set of deltas to
// match a new span layout that adds buckets, we simply need to generate a list
// of interjections.
// Note for histograms with delta-encoded buckets: Whenever any new buckets are
// introduced, the subsequent "old" bucket needs to readjust its delta to the
// new base of 0. Thus, for the caller who wants to transform the set of
// original deltas to a new set of deltas to match a new span layout that adds
// buckets, we simply need to generate a list of inserts.
//
// Note: Within forwardCompareSpans we don't have to worry about the changes to the
// Note: Within expandSpansForward we don't have to worry about the changes to the
// spans themselves, thanks to the iterators we get to work with the more useful
// bucket indices (which of course directly correspond to the buckets we have to
// adjust).
func forwardCompareSpans(a, b []histogram.Span) (forward []Interjection, ok bool) {
func expandSpansForward(a, b []histogram.Span) (forward []Insert, ok bool) {
ai := newBucketIterator(a)
bi := newBucketIterator(b)
var interjections []Interjection
var inserts []Insert
// When inter.num becomes > 0, this becomes a valid interjection that
// should be yielded when we finish a streak of new buckets.
var inter Interjection
// When inter.num becomes > 0, this becomes a valid insert that should
// be yielded when we finish a streak of new buckets.
var inter Insert
av, aOK := ai.Next()
bv, bOK := bi.Next()
@ -250,43 +250,46 @@ loop:
case aOK && bOK:
switch {
case av == bv: // Both have an identical value. move on!
// Finish WIP interjection and reset.
// Finish WIP insert and reset.
if inter.num > 0 {
interjections = append(interjections, inter)
inserts = append(inserts, inter)
}
inter.num = 0
av, aOK = ai.Next()
bv, bOK = bi.Next()
inter.pos++
case av < bv: // b misses a value that is in a.
return interjections, false
return inserts, false
case av > bv: // a misses a value that is in b. Forward b and recompare.
inter.num++
bv, bOK = bi.Next()
}
case aOK && !bOK: // b misses a value that is in a.
return interjections, false
return inserts, false
case !aOK && bOK: // a misses a value that is in b. Forward b and recompare.
inter.num++
bv, bOK = bi.Next()
default: // Both iterators ran out. We're done.
if inter.num > 0 {
interjections = append(interjections, inter)
inserts = append(inserts, inter)
}
break loop
}
}
return interjections, true
return inserts, true
}
// bidirectionalCompareSpans does everything that forwardCompareSpans does and
// also returns interjections in the other direction (i.e. buckets missing in b that are missing in a).
func bidirectionalCompareSpans(a, b []histogram.Span) (forward, backward []Interjection, mergedSpans []histogram.Span) {
// expandSpansBothWays is similar to expandSpansForward, but now b may also
// cover an entirely different set of buckets. The function returns the
// “forward” inserts to expand 'a' to also cover all the buckets exclusively
// covered by 'b', and it returns the “backward” inserts to expand 'b' to also
// cover all the buckets exclusively covered by 'a'
func expandSpansBothWays(a, b []histogram.Span) (forward, backward []Insert, mergedSpans []histogram.Span) {
ai := newBucketIterator(a)
bi := newBucketIterator(b)
var interjections, bInterjections []Interjection
var fInserts, bInserts []Insert
var lastBucket int
addBucket := func(b int) {
offset := b - lastBucket - 1
@ -305,9 +308,10 @@ func bidirectionalCompareSpans(a, b []histogram.Span) (forward, backward []Inter
lastBucket = b
}
// When inter.num becomes > 0, this becomes a valid interjection that
// should be yielded when we finish a streak of new buckets.
var inter, bInter Interjection
// When fInter.num (or bInter.num, respectively) becomes > 0, this
// becomes a valid insert that should be yielded when we finish a streak
// of new buckets.
var fInter, bInter Insert
av, aOK := ai.Next()
bv, bOK := bi.Next()
@ -317,37 +321,37 @@ loop:
case aOK && bOK:
switch {
case av == bv: // Both have an identical value. move on!
// Finish WIP interjection and reset.
if inter.num > 0 {
interjections = append(interjections, inter)
inter.num = 0
// Finish WIP insert and reset.
if fInter.num > 0 {
fInserts = append(fInserts, fInter)
fInter.num = 0
}
if bInter.num > 0 {
bInterjections = append(bInterjections, bInter)
bInserts = append(bInserts, bInter)
bInter.num = 0
}
addBucket(av)
av, aOK = ai.Next()
bv, bOK = bi.Next()
inter.pos++
fInter.pos++
bInter.pos++
case av < bv: // b misses a value that is in a.
bInter.num++
// Collect the forward interjection before advancing the
// position of 'a'.
if inter.num > 0 {
interjections = append(interjections, inter)
inter.num = 0
// Collect the forward inserts before advancing
// the position of 'a'.
if fInter.num > 0 {
fInserts = append(fInserts, fInter)
fInter.num = 0
}
addBucket(av)
inter.pos++
fInter.pos++
av, aOK = ai.Next()
case av > bv: // a misses a value that is in b. Forward b and recompare.
inter.num++
// Collect the backward interjection before advancing the
fInter.num++
// Collect the backward inserts before advancing the
// position of 'b'.
if bInter.num > 0 {
bInterjections = append(bInterjections, bInter)
bInserts = append(bInserts, bInter)
bInter.num = 0
}
addBucket(bv)
@ -359,92 +363,92 @@ loop:
addBucket(av)
av, aOK = ai.Next()
case !aOK && bOK: // a misses a value that is in b. Forward b and recompare.
inter.num++
fInter.num++
addBucket(bv)
bv, bOK = bi.Next()
default: // Both iterators ran out. We're done.
if inter.num > 0 {
interjections = append(interjections, inter)
if fInter.num > 0 {
fInserts = append(fInserts, fInter)
}
if bInter.num > 0 {
bInterjections = append(bInterjections, bInter)
bInserts = append(bInserts, bInter)
}
break loop
}
}
return interjections, bInterjections, mergedSpans
return fInserts, bInserts, mergedSpans
}
type bucketValue interface {
int64 | float64
}
// interject merges 'in' with the provided interjections and writes them into
// 'out', which must already have the appropriate length.
func interject[BV bucketValue](in, out []BV, interjections []Interjection, deltas bool) []BV {
// insert merges 'in' with the provided inserts and writes them into 'out',
// which must already have the appropriate length. 'out' is also returned for
// convenience.
func insert[BV bucketValue](in, out []BV, inserts []Insert, deltas bool) []BV {
var (
j int // Position in out.
v BV // The last value seen.
interj int // The next interjection to process.
oi int // Position in out.
v BV // The last value seen.
ii int // The next insert to process.
)
for i, d := range in {
if interj < len(interjections) && i == interjections[interj].pos {
// We have an interjection!
// Add interjection.num new delta values such that their bucket values equate 0.
// When deltas==false, it means that it is an absolute value. So we set it to 0 directly.
if ii < len(inserts) && i == inserts[ii].pos {
// We have an insert!
// Add insert.num new delta values such that their
// bucket values equate 0. When deltas==false, it means
// that it is an absolute value. So we set it to 0
// directly.
if deltas {
out[j] = -v
out[oi] = -v
} else {
out[j] = 0
out[oi] = 0
}
j++
for x := 1; x < interjections[interj].num; x++ {
out[j] = 0
j++
oi++
for x := 1; x < inserts[ii].num; x++ {
out[oi] = 0
oi++
}
interj++
ii++
// Now save the value from the input. The delta value we
// should save is the original delta value + the last
// value of the point before the interjection (to undo
// the delta that was introduced by the interjection).
// When deltas==false, it means that it is an absolute value,
// value of the point before the insert (to undo the
// delta that was introduced by the insert). When
// deltas==false, it means that it is an absolute value,
// so we set it directly to the value in the 'in' slice.
if deltas {
out[j] = d + v
out[oi] = d + v
} else {
out[j] = d
out[oi] = d
}
j++
oi++
v = d + v
continue
}
// If there was no interjection, the original delta is still
// valid.
out[j] = d
j++
// If there was no insert, the original delta is still valid.
out[oi] = d
oi++
v += d
}
switch interj {
case len(interjections):
// All interjections processed. Nothing more to do.
case len(interjections) - 1:
// One more interjection to process at the end.
switch ii {
case len(inserts):
// All inserts processed. Nothing more to do.
case len(inserts) - 1:
// One more insert to process at the end.
if deltas {
out[j] = -v
out[oi] = -v
} else {
out[j] = 0
out[oi] = 0
}
j++
for x := 1; x < interjections[interj].num; x++ {
out[j] = 0
j++
oi++
for x := 1; x < inserts[ii].num; x++ {
out[oi] = 0
oi++
}
default:
panic("unprocessed interjections left")
panic("unprocessed inserts left")
}
return out
}

View file

@ -78,7 +78,7 @@ func TestBucketIterator(t *testing.T) {
},
idxs: []int{100, 101, 102, 103, 112, 113, 114, 115, 116, 117, 118, 119},
},
// The below 2 sets ore the ones described in compareSpans's comments.
// The below 2 sets ore the ones described in expandSpansForward's comments.
{
spans: []histogram.Span{
{Offset: 0, Length: 2},
@ -111,12 +111,12 @@ func TestBucketIterator(t *testing.T) {
}
}
func TestCompareSpansAndInterject(t *testing.T) {
func TestCompareSpansAndInsert(t *testing.T) {
scenarios := []struct {
description string
spansA, spansB []histogram.Span
interjections, backwardInterjections []Interjection
bucketsIn, bucketsOut []int64
description string
spansA, spansB []histogram.Span
fInserts, bInserts []Insert
bucketsIn, bucketsOut []int64
}{
{
description: "single prepend at the beginning",
@ -126,7 +126,7 @@ func TestCompareSpansAndInterject(t *testing.T) {
spansB: []histogram.Span{
{Offset: -11, Length: 4},
},
interjections: []Interjection{
fInserts: []Insert{
{
pos: 0,
num: 1,
@ -143,7 +143,7 @@ func TestCompareSpansAndInterject(t *testing.T) {
spansB: []histogram.Span{
{Offset: -10, Length: 4},
},
interjections: []Interjection{
fInserts: []Insert{
{
pos: 3,
num: 1,
@ -160,7 +160,7 @@ func TestCompareSpansAndInterject(t *testing.T) {
spansB: []histogram.Span{
{Offset: -12, Length: 5},
},
interjections: []Interjection{
fInserts: []Insert{
{
pos: 0,
num: 2,
@ -177,7 +177,7 @@ func TestCompareSpansAndInterject(t *testing.T) {
spansB: []histogram.Span{
{Offset: -10, Length: 5},
},
interjections: []Interjection{
fInserts: []Insert{
{
pos: 3,
num: 2,
@ -194,7 +194,7 @@ func TestCompareSpansAndInterject(t *testing.T) {
spansB: []histogram.Span{
{Offset: -12, Length: 7},
},
interjections: []Interjection{
fInserts: []Insert{
{
pos: 0,
num: 2,
@ -215,7 +215,7 @@ func TestCompareSpansAndInterject(t *testing.T) {
spansB: []histogram.Span{
{Offset: -9, Length: 3},
},
backwardInterjections: []Interjection{
bInserts: []Insert{
{pos: 0, num: 1},
},
},
@ -228,7 +228,7 @@ func TestCompareSpansAndInterject(t *testing.T) {
{Offset: -10, Length: 2},
{Offset: 1, Length: 1},
},
backwardInterjections: []Interjection{
bInserts: []Insert{
{pos: 2, num: 1},
},
},
@ -240,7 +240,7 @@ func TestCompareSpansAndInterject(t *testing.T) {
spansB: []histogram.Span{
{Offset: -10, Length: 3},
},
backwardInterjections: []Interjection{
bInserts: []Insert{
{pos: 3, num: 1},
},
},
@ -259,7 +259,7 @@ func TestCompareSpansAndInterject(t *testing.T) {
{Offset: 1, Length: 4},
{Offset: 3, Length: 3},
},
interjections: []Interjection{
fInserts: []Insert{
{
pos: 2,
num: 1,
@ -277,7 +277,7 @@ func TestCompareSpansAndInterject(t *testing.T) {
bucketsOut: []int64{6, -3, -3, 3, -3, 0, 2, 2, 1, -5, 1},
},
{
description: "both forward and backward interjections, complex case",
description: "both forward and backward inserts, complex case",
spansA: []histogram.Span{
{Offset: 0, Length: 2},
{Offset: 2, Length: 1},
@ -292,7 +292,7 @@ func TestCompareSpansAndInterject(t *testing.T) {
{Offset: 1, Length: 1},
{Offset: 4, Length: 1},
},
interjections: []Interjection{
fInserts: []Insert{
{
pos: 2,
num: 1,
@ -306,7 +306,7 @@ func TestCompareSpansAndInterject(t *testing.T) {
num: 1,
},
},
backwardInterjections: []Interjection{
bInserts: []Insert{
{
pos: 0,
num: 1,
@ -329,22 +329,22 @@ func TestCompareSpansAndInterject(t *testing.T) {
for _, s := range scenarios {
t.Run(s.description, func(t *testing.T) {
if len(s.backwardInterjections) > 0 {
interjections, bInterjections, _ := bidirectionalCompareSpans(s.spansA, s.spansB)
require.Equal(t, s.interjections, interjections)
require.Equal(t, s.backwardInterjections, bInterjections)
if len(s.bInserts) > 0 {
fInserts, bInserts, _ := expandSpansBothWays(s.spansA, s.spansB)
require.Equal(t, s.fInserts, fInserts)
require.Equal(t, s.bInserts, bInserts)
}
interjections, valid := forwardCompareSpans(s.spansA, s.spansB)
if len(s.backwardInterjections) > 0 {
inserts, valid := expandSpansForward(s.spansA, s.spansB)
if len(s.bInserts) > 0 {
require.False(t, valid, "compareScan unexpectedly returned true")
return
}
require.True(t, valid, "compareScan unexpectedly returned false")
require.Equal(t, s.interjections, interjections)
require.Equal(t, s.fInserts, inserts)
gotBuckets := make([]int64, len(s.bucketsOut))
interject(s.bucketsIn, gotBuckets, interjections, true)
insert(s.bucketsIn, gotBuckets, inserts, true)
require.Equal(t, s.bucketsOut, gotBuckets)
floatBucketsIn := make([]float64, len(s.bucketsIn))
@ -362,7 +362,7 @@ func TestCompareSpansAndInterject(t *testing.T) {
floatBucketsOut[i] = float64(last)
}
gotFloatBuckets := make([]float64, len(floatBucketsOut))
interject(floatBucketsIn, gotFloatBuckets, interjections, false)
insert(floatBucketsIn, gotFloatBuckets, inserts, false)
require.Equal(t, floatBucketsOut, gotFloatBuckets)
})
}
@ -564,12 +564,12 @@ func TestSpansFromBidirectionalCompareSpans(t *testing.T) {
copy(s1c, c.s1)
copy(s2c, c.s2)
_, _, act := bidirectionalCompareSpans(c.s1, c.s2)
_, _, act := expandSpansBothWays(c.s1, c.s2)
require.Equal(t, c.exp, act)
// Check that s1 and s2 are not modified.
require.Equal(t, s1c, c.s1)
require.Equal(t, s2c, c.s2)
_, _, act = bidirectionalCompareSpans(c.s2, c.s1)
_, _, act = expandSpansBothWays(c.s2, c.s1)
require.Equal(t, c.exp, act)
}
}

View file

@ -149,7 +149,7 @@ func TestHistogramChunkSameBuckets(t *testing.T) {
require.Equal(t, ValNone, it4.Seek(exp[len(exp)-1].t+1))
}
// Mimics the scenario described for compareSpans().
// Mimics the scenario described for expandSpansForward.
func TestHistogramChunkBucketChanges(t *testing.T) {
c := Chunk(NewHistogramChunk())

View file

@ -1141,7 +1141,6 @@ func (s *memSeries) append(t int64, v float64, appendID uint64, chunkDiskMapper
// appendHistogram adds the histogram.
// It is unsafe to call this concurrently with s.iterator(...) without holding the series lock.
// TODO(codesome): Support gauge histograms here.
func (s *memSeries) appendHistogram(t int64, h *histogram.Histogram, appendID uint64, chunkDiskMapper *chunks.ChunkDiskMapper, chunkRange int64) (sampleInOrder, chunkCreated bool) {
// Head controls the execution of recoding, so that we own the proper
// chunk reference afterwards. We check for Appendable from appender before
@ -1150,10 +1149,10 @@ func (s *memSeries) appendHistogram(t int64, h *histogram.Histogram, appendID ui
// meta properly.
app, _ := s.app.(*chunkenc.HistogramAppender)
var (
positiveInterjections, negativeInterjections []chunkenc.Interjection
pBackwardInter, nBackwardInter []chunkenc.Interjection
pMergedSpans, nMergedSpans []histogram.Span
okToAppend, counterReset bool
pForwardInserts, nForwardInserts []chunkenc.Insert
pBackwardInserts, nBackwardInserts []chunkenc.Insert
pMergedSpans, nMergedSpans []histogram.Span
okToAppend, counterReset bool
)
c, sampleInOrder, chunkCreated := s.appendPreprocessor(t, chunkenc.EncHistogram, chunkDiskMapper, chunkRange)
if !sampleInOrder {
@ -1162,32 +1161,32 @@ func (s *memSeries) appendHistogram(t int64, h *histogram.Histogram, appendID ui
gauge := h.CounterResetHint == histogram.GaugeType
if app != nil {
if gauge {
positiveInterjections, negativeInterjections, pBackwardInter, nBackwardInter, pMergedSpans, nMergedSpans, okToAppend = app.AppendableGauge(h)
pForwardInserts, nForwardInserts, pBackwardInserts, nBackwardInserts, pMergedSpans, nMergedSpans, okToAppend = app.AppendableGauge(h)
} else {
positiveInterjections, negativeInterjections, okToAppend, counterReset = app.Appendable(h)
pForwardInserts, nForwardInserts, okToAppend, counterReset = app.Appendable(h)
}
}
if !chunkCreated {
if len(pBackwardInter)+len(nBackwardInter) > 0 {
if len(pBackwardInserts)+len(nBackwardInserts) > 0 {
h.PositiveSpans = pMergedSpans
h.NegativeSpans = nMergedSpans
app.RecodeHistogram(h, pBackwardInter, nBackwardInter)
app.RecodeHistogram(h, pBackwardInserts, nBackwardInserts)
}
// We have 3 cases here
// - !okToAppend -> We need to cut a new chunk.
// - okToAppend but we have interjections → Existing chunk needs
// - okToAppend but we have inserts → Existing chunk needs
// recoding before we can append our histogram.
// - okToAppend and no interjections → Chunk is ready to support our histogram.
// - okToAppend and no inserts → Chunk is ready to support our histogram.
if !okToAppend || counterReset {
c = s.cutNewHeadChunk(t, chunkenc.EncHistogram, chunkDiskMapper, chunkRange)
chunkCreated = true
} else if len(positiveInterjections) > 0 || len(negativeInterjections) > 0 {
} else if len(pForwardInserts) > 0 || len(nForwardInserts) > 0 {
// New buckets have appeared. We need to recode all
// prior histogram samples within the chunk before we
// can process this one.
chunk, app := app.Recode(
positiveInterjections, negativeInterjections,
pForwardInserts, nForwardInserts,
h.PositiveSpans, h.NegativeSpans,
)
c.chunk = chunk
@ -1233,10 +1232,10 @@ func (s *memSeries) appendFloatHistogram(t int64, fh *histogram.FloatHistogram,
// meta properly.
app, _ := s.app.(*chunkenc.FloatHistogramAppender)
var (
positiveInterjections, negativeInterjections []chunkenc.Interjection
pBackwardInter, nBackwardInter []chunkenc.Interjection
pMergedSpans, nMergedSpans []histogram.Span
okToAppend, counterReset bool
pForwardInserts, nForwardInserts []chunkenc.Insert
pBackwardInserts, nBackwardInserts []chunkenc.Insert
pMergedSpans, nMergedSpans []histogram.Span
okToAppend, counterReset bool
)
c, sampleInOrder, chunkCreated := s.appendPreprocessor(t, chunkenc.EncFloatHistogram, chunkDiskMapper, chunkRange)
if !sampleInOrder {
@ -1245,33 +1244,33 @@ func (s *memSeries) appendFloatHistogram(t int64, fh *histogram.FloatHistogram,
gauge := fh.CounterResetHint == histogram.GaugeType
if app != nil {
if gauge {
positiveInterjections, negativeInterjections, pBackwardInter, nBackwardInter,
pForwardInserts, nForwardInserts, pBackwardInserts, nBackwardInserts,
pMergedSpans, nMergedSpans, okToAppend = app.AppendableGauge(fh)
} else {
positiveInterjections, negativeInterjections, okToAppend, counterReset = app.Appendable(fh)
pForwardInserts, nForwardInserts, okToAppend, counterReset = app.Appendable(fh)
}
}
if !chunkCreated {
if len(pBackwardInter)+len(nBackwardInter) > 0 {
if len(pBackwardInserts)+len(nBackwardInserts) > 0 {
fh.PositiveSpans = pMergedSpans
fh.NegativeSpans = nMergedSpans
app.RecodeHistogramm(fh, pBackwardInter, nBackwardInter)
app.RecodeHistogramm(fh, pBackwardInserts, nBackwardInserts)
}
// We have 3 cases here
// - !okToAppend -> We need to cut a new chunk.
// - okToAppend but we have interjections → Existing chunk needs
// - okToAppend but we have inserts → Existing chunk needs
// recoding before we can append our histogram.
// - okToAppend and no interjections → Chunk is ready to support our histogram.
// - okToAppend and no inserts → Chunk is ready to support our histogram.
if !okToAppend || counterReset {
c = s.cutNewHeadChunk(t, chunkenc.EncFloatHistogram, chunkDiskMapper, chunkRange)
chunkCreated = true
} else if len(positiveInterjections) > 0 || len(negativeInterjections) > 0 {
} else if len(pForwardInserts) > 0 || len(nForwardInserts) > 0 {
// New buckets have appeared. We need to recode all
// prior histogram samples within the chunk before we
// can process this one.
chunk, app := app.Recode(
positiveInterjections, negativeInterjections,
pForwardInserts, nForwardInserts,
fh.PositiveSpans, fh.NegativeSpans,
)
c.chunk = chunk