// ValueAtTime implements SeriesIterator.
func (it *memorySeriesIterator) ValueAtTime(t clientmodel.Timestamp) metric.Values {
// The most common case. We are iterating through a chunk.
if it.chunkIt != nil && it.chunkIt.contains(t) {
return it.chunkIt.valueAtTime(t)
}
if len(it.chunks) == 0 {
return nil
}
// Before or exactly on the first sample of the series.
it.chunkIt = it.chunkIterator(0)
ts := it.chunkIt.timestampAtIndex(0)
if !t.After(ts) {
// return first value of first chunk
return metric.Values{metric.SamplePair{
Timestamp: ts,
Value: it.chunkIt.sampleValueAtIndex(0),
}}
}
// After or exactly on the last sample of the series.
it.chunkIt = it.chunkIterator(len(it.chunks) - 1)
ts = it.chunkIt.lastTimestamp()
if !t.Before(ts) {
// return last value of last chunk
return metric.Values{metric.SamplePair{
Timestamp: ts,
Value: it.chunkIt.sampleValueAtIndex(it.chunkIt.length() - 1),
}}
}
// Find last chunk where firstTime() is before or equal to t.
l := len(it.chunks) - 1
i := sort.Search(len(it.chunks), func(i int) bool {
return !it.chunks[l-i].firstTime().After(t)
})
if i == len(it.chunks) {
panic("out of bounds")
}
it.chunkIt = it.chunkIterator(l - i)
ts = it.chunkIt.lastTimestamp()
if t.After(ts) {
// We ended up between two chunks.
sp1 := metric.SamplePair{
Timestamp: ts,
Value: it.chunkIt.sampleValueAtIndex(it.chunkIt.length() - 1),
}
it.chunkIt = it.chunkIterator(l - i + 1)
return metric.Values{
sp1,
metric.SamplePair{
Timestamp: it.chunkIt.timestampAtIndex(0),
Value: it.chunkIt.sampleValueAtIndex(0),
},
}
}
return it.chunkIt.valueAtTime(t)
}
// MayContain indicates whether the given SampleKey could potentially contain a
// value at the provided time. Even if true is emitted, that does not mean a
// satisfactory value, in fact, exists.
func (s *SampleKey) MayContain(t clientmodel.Timestamp) bool {
switch {
case t.Before(s.FirstTimestamp):
return false
case t.After(s.LastTimestamp):
return false
default:
return true
}
}
// GetValueAtTime implements SeriesIterator.
func (it *memorySeriesIterator) GetValueAtTime(t clientmodel.Timestamp) metric.Values {
it.lock()
defer it.unlock()
// The most common case. We are iterating through a chunk.
if it.chunkIt != nil && it.chunkIt.contains(t) {
return it.chunkIt.getValueAtTime(t)
}
it.chunkIt = nil
if len(it.chunks) == 0 {
return nil
}
// Before or exactly on the first sample of the series.
if !t.After(it.chunks[0].firstTime()) {
// return first value of first chunk
return it.chunks[0].newIterator().getValueAtTime(t)
}
// After or exactly on the last sample of the series.
if !t.Before(it.chunks[len(it.chunks)-1].lastTime()) {
// return last value of last chunk
return it.chunks[len(it.chunks)-1].newIterator().getValueAtTime(t)
}
// Find first chunk where lastTime() is after or equal to t.
i := sort.Search(len(it.chunks), func(i int) bool {
return !it.chunks[i].lastTime().Before(t)
})
if i == len(it.chunks) {
panic("out of bounds")
}
if t.Before(it.chunks[i].firstTime()) {
// We ended up between two chunks.
return metric.Values{
it.chunks[i-1].newIterator().getValueAtTime(t)[0],
it.chunks[i].newIterator().getValueAtTime(t)[0],
}
}
// We ended up in the middle of a chunk. We might stay there for a while,
// so save it as the current chunk iterator.
it.chunkIt = it.chunks[i].newIterator()
return it.chunkIt.getValueAtTime(t)
}
// contains implements chunkIterator.
func (it *deltaEncodedChunkIterator) contains(t clientmodel.Timestamp) bool {
return !t.Before(it.baseT) && !t.After(it.timestampAtIndex(it.len-1))
}
func (t *TieredStorage) loadChunkAroundTime(
iterator leveldb.Iterator,
fingerprint *clientmodel.Fingerprint,
ts clientmodel.Timestamp,
firstBlock,
lastBlock *SampleKey,
) (chunk metric.Values, expired bool) {
if fingerprint.Less(firstBlock.Fingerprint) {
return nil, false
}
if lastBlock.Fingerprint.Less(fingerprint) {
return nil, true
}
seekingKey, _ := t.sampleKeys.Get()
defer t.sampleKeys.Give(seekingKey)
seekingKey.Fingerprint = fingerprint
if fingerprint.Equal(firstBlock.Fingerprint) && ts.Before(firstBlock.FirstTimestamp) {
seekingKey.FirstTimestamp = firstBlock.FirstTimestamp
} else if fingerprint.Equal(lastBlock.Fingerprint) && ts.After(lastBlock.FirstTimestamp) {
seekingKey.FirstTimestamp = lastBlock.FirstTimestamp
} else {
seekingKey.FirstTimestamp = ts
}
dto, _ := t.dtoSampleKeys.Get()
defer t.dtoSampleKeys.Give(dto)
seekingKey.Dump(dto)
if !iterator.Seek(dto) {
return chunk, true
}
var foundValues metric.Values
if err := iterator.Key(dto); err != nil {
panic(err)
}
seekingKey.Load(dto)
if seekingKey.Fingerprint.Equal(fingerprint) {
// Figure out if we need to rewind by one block.
// Imagine the following supertime blocks with time ranges:
//
// Block 1: ft 1000 - lt 1009 <data>
// Block 1: ft 1010 - lt 1019 <data>
//
// If we are aiming to find time 1005, we would first seek to the block with
// supertime 1010, then need to rewind by one block by virtue of LevelDB
// iterator seek behavior.
//
// Only do the rewind if there is another chunk before this one.
if !seekingKey.MayContain(ts) {
postValues := unmarshalValues(iterator.RawValue(), nil)
if !seekingKey.Equal(firstBlock) {
if !iterator.Previous() {
panic("This should never return false.")
}
if err := iterator.Key(dto); err != nil {
panic(err)
}
seekingKey.Load(dto)
if !seekingKey.Fingerprint.Equal(fingerprint) {
return postValues, false
}
foundValues = unmarshalValues(iterator.RawValue(), nil)
foundValues = append(foundValues, postValues...)
return foundValues, false
}
}
foundValues = unmarshalValues(iterator.RawValue(), nil)
return foundValues, false
}
if fingerprint.Less(seekingKey.Fingerprint) {
if !seekingKey.Equal(firstBlock) {
if !iterator.Previous() {
panic("This should never return false.")
}
if err := iterator.Key(dto); err != nil {
panic(err)
}
seekingKey.Load(dto)
if !seekingKey.Fingerprint.Equal(fingerprint) {
return nil, false
}
foundValues = unmarshalValues(iterator.RawValue(), nil)
return foundValues, false
}
}
panic("illegal state: violated sort invariant")
}
func (cd *chunkDesc) contains(t clientmodel.Timestamp) bool {
return !t.Before(cd.firstTime()) && !t.After(cd.lastTime())
}
// contains implements chunkIterator.
func (it *deltaEncodedChunkIterator) contains(t clientmodel.Timestamp) bool {
return !t.Before(it.chunk.firstTime()) && !t.After(it.chunk.lastTime())
}