mirrors/prometheus
1
0
Fork 0
mirror of https://github.com/prometheus/prometheus.git synced 2026-05-05 12:26:14 +02:00
Code Issues Projects Releases Wiki Activity

tsdb: fix grow/shrink nextIndex calculation (#17863)

Browse Source 
Signed-off-by: Julius Hinze <julius.hinze@grafana.com>
This commit is contained in:
Julius Hinze 2026-01-14 16:44:50 +01:00 committed by GitHub
parent 3374d2e56f
commit ccb7468b09
No known key found for this signature in database
GPG Key ID: B5690EEEBB952194
2 changed files with 57 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
tsdb/exemplar.go
View File

@ -327,7 +327,8 @@ func (ce *CircularExemplarStorage) grow(l int64) int {
{from: ce.nextIndex, to: oldSize},
{from: 0, to: ce.nextIndex},
}
ce.nextIndex = copyExemplarRanges(ce.index, newSlice, ce.exemplars, ranges)
totalCopied, _ := copyExemplarRanges(ce.index, newSlice, ce.exemplars, ranges)
ce.nextIndex = totalCopied
ce.exemplars = newSlice
return oldSize
}
@ -353,6 +354,7 @@ func (ce *CircularExemplarStorage) shrink(l int64) (migrated int) {
newSlice := make([]circularBufferEntry, int(l))
var totalCopied int
switch {
case deleteStart == deleteEnd:
// The entire buffer was cleared (shrink to zero). Note that we don't have to
@ -363,18 +365,18 @@ func (ce *CircularExemplarStorage) shrink(l int64) (migrated int) {
return 0
case deleteStart < deleteEnd:
// We delete an "inner" section of the circular buffer.
migrated = copyExemplarRanges(ce.index, newSlice, ce.exemplars, []intRange{
totalCopied, migrated = copyExemplarRanges(ce.index, newSlice, ce.exemplars, []intRange{
{from: deleteEnd, to: oldSize},
{from: 0, to: deleteStart},
})
case deleteStart > deleteEnd:
// We keep an "inner" section of the circular buffer.
migrated = copyExemplarRanges(ce.index, newSlice, ce.exemplars, []intRange{
totalCopied, migrated = copyExemplarRanges(ce.index, newSlice, ce.exemplars, []intRange{
{from: deleteEnd, to: deleteStart},
})
}
ce.nextIndex = migrated % int(l)
ce.nextIndex = totalCopied % int(l)
ce.exemplars = newSlice
return migrated
}
@ -582,20 +584,21 @@ func (e intRange) contains(i int) bool {
}
// copyExemplarRanges copies non-overlapping ranges from src into dest and
// adjusts list pointers in dest and index accordingly. Returns the number of
// copied items.
// adjusts list pointers in dest and index accordingly. Returns the total
// number of slots copied (for nextIndex) and the number of non-empty entries
// migrated.
func copyExemplarRanges(
index map[string]*indexEntry,
dest, src []circularBufferEntry,
ranges []intRange,
) int {
) (totalCopied, migratedEntries int) {
offsets := make([]int, len(ranges))
n := 0
for i, rng := range ranges {
offsets[i] = n - rng.from
n += copy(dest[n:], src[rng.from:rng.to])
}
migratedEntries := n
migratedEntries = n
for di := range n {
e := &dest[di]
if e.ref == nil {
@ -631,5 +634,5 @@ func copyExemplarRanges(
}
}
}
return migratedEntries
return n, migratedEntries
}

49
tsdb/exemplar_test.go
View File

@ -390,7 +390,7 @@ func TestCircularExemplarStorage_Resize(t *testing.T) {
{Labels: series1, Value: 0.1, Ts: 1},
{Labels: series1, Value: 0.2, Ts: 2},
},
wantNextIndex: 2,
wantNextIndex: 3,
},
{
name: "in-order, shrink",
@ -431,7 +431,7 @@ func TestCircularExemplarStorage_Resize(t *testing.T) {
{Labels: series1, Value: 0.2, Ts: 2},
{Labels: series1, Value: 0.3, Ts: 3},
},
wantNextIndex: 2,
wantNextIndex: 3,
},
{
name: "duplicate timestamps",
@ -452,7 +452,7 @@ func TestCircularExemplarStorage_Resize(t *testing.T) {
exemplars: []exemplar.Exemplar{},
resize: 10,
wantExemplars: []exemplar.Exemplar{},
wantNextIndex: 0,
wantNextIndex: 3,
},
{
name: "empty input, shrink",
@ -507,7 +507,7 @@ func TestCircularExemplarStorage_Resize(t *testing.T) {
wantExemplars: []exemplar.Exemplar{
{Labels: series1, Value: 0.1, Ts: 1},
},
wantNextIndex: 1,
wantNextIndex: 0,
},
}
@ -660,6 +660,47 @@ func TestCircularExemplarStorage_Resize(t *testing.T) {
{Labels: series1, Value: 0.6, Ts: 6},
},
},
{
name: "grow non-full buffer then add entries",
addExemplars1: []exemplar.Exemplar{
{Labels: series1, Value: 0.1, Ts: 1},
{Labels: series1, Value: 0.2, Ts: 2},
},
resize1: 10,
wantExemplars1: []exemplar.Exemplar{
{Labels: series1, Value: 0.1, Ts: 1},
{Labels: series1, Value: 0.2, Ts: 2},
},
resize2: 10,
addExemplars2: []exemplar.Exemplar{
{Labels: series1, Value: 0.3, Ts: 3},
{Labels: series1, Value: 0.4, Ts: 4},
},
wantExemplars2: []exemplar.Exemplar{
{Labels: series1, Value: 0.1, Ts: 1},
{Labels: series1, Value: 0.2, Ts: 2},
{Labels: series1, Value: 0.3, Ts: 3},
{Labels: series1, Value: 0.4, Ts: 4},
},
},
{
name: "shrink non-full buffer then add entries",
addExemplars1: []exemplar.Exemplar{
{Labels: series1, Value: 0.1, Ts: 1},
},
resize1: 2,
wantExemplars1: []exemplar.Exemplar{
{Labels: series1, Value: 0.1, Ts: 1},
},
resize2: 2,
addExemplars2: []exemplar.Exemplar{
{Labels: series1, Value: 0.2, Ts: 2},
},
wantExemplars2: []exemplar.Exemplar{
{Labels: series1, Value: 0.1, Ts: 1},
{Labels: series1, Value: 0.2, Ts: 2},
},
},
}
for _, tc := range resizeTwiceCases {