// newSeriesFrontier furnishes a populated diskFrontier for a given
// fingerprint. A nil diskFrontier will be returned if the series cannot
// be found in the store.
func newSeriesFrontier(f model.Fingerprint, d diskFrontier, i leveldb.Iterator) (s *seriesFrontier, err error) {
var (
lowerSeek = firstSupertime
upperSeek = lastSupertime
)
// If the diskFrontier for this iterator says that the candidate fingerprint
// is outside of its seeking domain, there is no way that a seriesFrontier
// could be materialized. Simply bail.
if !d.ContainsFingerprint(f) {
return
}
// If we are either the first or the last key in the database, we need to use
// pessimistic boundary frontiers.
if f.Equal(d.firstFingerprint) {
lowerSeek = indexable.EncodeTime(d.firstSupertime)
}
if f.Equal(d.lastFingerprint) {
upperSeek = indexable.EncodeTime(d.lastSupertime)
}
key := &dto.SampleKey{
Fingerprint: f.ToDTO(),
Timestamp: upperSeek,
}
raw, err := coding.NewProtocolBuffer(key).Encode()
if err != nil {
panic(err)
}
i.Seek(raw)
if i.Key() == nil {
return
}
retrievedKey, err := extractSampleKey(i)
if err != nil {
panic(err)
}
retrievedFingerprint := model.NewFingerprintFromRowKey(*retrievedKey.Fingerprint.Signature)
// The returned fingerprint may not match if the original seek key lives
// outside of a metric's frontier. This is probable, for we are seeking to
// to the maximum allowed time, which could advance us to the next
// fingerprint.
//
//
if !retrievedFingerprint.Equal(f) {
i.Previous()
retrievedKey, err = extractSampleKey(i)
if err != nil {
panic(err)
}
retrievedFingerprint := model.NewFingerprintFromRowKey(*retrievedKey.Fingerprint.Signature)
// If the previous key does not match, we know that the requested
// fingerprint does not live in the database.
if !retrievedFingerprint.Equal(f) {
return
}
}
s = &seriesFrontier{
lastSupertime: indexable.DecodeTime(retrievedKey.Timestamp),
lastTime: time.Unix(*retrievedKey.LastTimestamp, 0),
}
key.Timestamp = lowerSeek
raw, err = coding.NewProtocolBuffer(key).Encode()
if err != nil {
panic(err)
}
i.Seek(raw)
retrievedKey, err = extractSampleKey(i)
if err != nil {
panic(err)
}
retrievedFingerprint = model.NewFingerprintFromRowKey(*retrievedKey.Fingerprint.Signature)
s.firstSupertime = indexable.DecodeTime(retrievedKey.Timestamp)
return
}
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 (t *tieredStorage) loadChunkAroundTime(iterator leveldb.Iterator, frontier *seriesFrontier, fingerprint model.Fingerprint, ts time.Time) (chunk []model.SamplePair) {
var (
targetKey = &dto.SampleKey{
Fingerprint: fingerprint.ToDTO(),
}
foundKey = &dto.SampleKey{}
foundValue *dto.SampleValueSeries
)
// Limit the target key to be within the series' keyspace.
if ts.After(frontier.lastSupertime) {
targetKey.Timestamp = indexable.EncodeTime(frontier.lastSupertime)
} else {
targetKey.Timestamp = indexable.EncodeTime(ts)
}
// Try seeking to target key.
rawKey, _ := coding.NewProtocolBuffer(targetKey).Encode()
iterator.Seek(rawKey)
foundKey, err := extractSampleKey(iterator)
if err != nil {
panic(err)
}
// 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.
rewound := false
firstTime := indexable.DecodeTime(foundKey.Timestamp)
if ts.Before(firstTime) && !frontier.firstSupertime.After(ts) {
iterator.Previous()
rewound = true
}
foundValue, err = extractSampleValues(iterator)
if err != nil {
panic(err)
}
// If we rewound, but the target time is still past the current block, return
// the last value of the current (rewound) block and the entire next block.
if rewound {
foundKey, err = extractSampleKey(iterator)
if err != nil {
panic(err)
}
currentChunkLastTime := time.Unix(*foundKey.LastTimestamp, 0)
if ts.After(currentChunkLastTime) {
sampleCount := len(foundValue.Value)
chunk = append(chunk, model.SamplePair{
Timestamp: time.Unix(*foundValue.Value[sampleCount-1].Timestamp, 0),
Value: model.SampleValue(*foundValue.Value[sampleCount-1].Value),
})
// We know there's a next block since we have rewound from it.
iterator.Next()
foundValue, err = extractSampleValues(iterator)
if err != nil {
panic(err)
}
}
}
// Now append all the samples of the currently seeked block to the output.
for _, sample := range foundValue.Value {
chunk = append(chunk, model.SamplePair{
Timestamp: time.Unix(*sample.Timestamp, 0),
Value: model.SampleValue(*sample.Value),
})
}
return
}