Add regression test for duplicate detection at chunk size limit

TestHeadDetectsDuplcateSampleAtSizeLimit tests a regression where a
 duplicate sample,is appended to the head, right when the head chunk is
 at the size limit. The test adds all samples as duplicate, thus
 expecting that the result has exactly half of the samples.

Signed-off-by: György Krajcsovits <gyorgy.krajcsovits@grafana.com>
This commit is contained in:
György Krajcsovits 2023-09-20 14:32:20 +02:00
parent 83891135c6
commit 56b3a015b6
1 changed files with 46 additions and 0 deletions

View File

@ -5499,3 +5499,49 @@ func TestCuttingNewHeadChunks(t *testing.T) {
})
}
}
// TestHeadDetectsDuplcateSampleAtSizeLimit tests a regression where a duplicate sample
// is appended to the head, right when the head chunk is at the size limit.
// The test adds all samples as duplicate, thus expecting that the result has
// exactly half of the samples.
func TestHeadDetectsDuplicateSampleAtSizeLimit(t *testing.T) {
numSamples := 1000
baseTS := int64(1695209650)
h, _ := newTestHead(t, DefaultBlockDuration, wlog.CompressionNone, false)
defer func() {
require.NoError(t, h.Close())
}()
a := h.Appender(context.Background())
var err error
vals := []float64{math.MaxFloat64, 0x00} // Use the worst case scenario for the XOR encoding. Otherwise we hit the sample limit before the size limit.
for i := 0; i < numSamples; i++ {
ts := baseTS + int64(i/2)*10000
a.Append(0, labels.FromStrings("foo", "bar"), ts, vals[(i/2)%len(vals)])
err = a.Commit()
require.NoError(t, err)
a = h.Appender(context.Background())
}
indexReader, err := h.Index()
require.NoError(t, err)
var (
chunks []chunks.Meta
builder labels.ScratchBuilder
)
require.NoError(t, indexReader.Series(1, &builder, &chunks))
chunkReader, err := h.Chunks()
require.NoError(t, err)
storedSampleCount := 0
for _, chunkMeta := range chunks {
chunk, err := chunkReader.Chunk(chunkMeta)
require.NoError(t, err)
storedSampleCount += chunk.NumSamples()
}
require.Equal(t, numSamples/2, storedSampleCount)
}