prometheus/head.go

131 lines
2.9 KiB
Go

package tsdb
import (
"math"
"sort"
"sync"
"github.com/fabxc/tsdb/chunks"
)
// HeadBlock handles reads and writes of time series data within a time window.
type HeadBlock struct {
mtx sync.RWMutex
descs map[uint64][]*chunkDesc // labels hash to possible chunks descs
index *memIndex
samples uint64 // total samples in the block
highTimestamp int64 // highest timestamp of any sample
baseTimestamp int64 // all samples are strictly later
}
// NewHeadBlock creates a new empty head block.
func NewHeadBlock(baseTime int64) *HeadBlock {
return &HeadBlock{
descs: make(map[uint64][]*chunkDesc, 2048),
index: newMemIndex(),
baseTimestamp: baseTime,
}
}
// Querier returns a new querier over the head block.
func (h *HeadBlock) Querier(mint, maxt int64) Querier {
return newBlockQuerier(h, h, mint, maxt)
}
func (h *HeadBlock) Chunk(ref uint32) (chunks.Chunk, error) {
c, ok := h.index.forward[ref]
if !ok {
return nil, errNotFound
}
return c.chunk, nil
}
// Stats returns statisitics about the indexed data.
func (h *HeadBlock) Stats() (*BlockStats, error) {
return nil, nil
}
// LabelValues returns the possible label values
func (h *HeadBlock) LabelValues(names ...string) (StringTuples, error) {
if len(names) != 1 {
return nil, errInvalidSize
}
var sl []string
for s := range h.index.values[names[0]] {
sl = append(sl, s)
}
sort.Strings(sl)
t := &stringTuples{
l: len(names),
s: sl,
}
return t, nil
}
// Postings returns the postings list iterator for the label pair.
func (h *HeadBlock) Postings(name, value string) (Postings, error) {
return h.index.Postings(term{name, value}), nil
}
// Series returns the series for the given reference.
func (h *HeadBlock) Series(ref uint32) (Series, error) {
cd, ok := h.index.forward[ref]
if !ok {
return nil, errNotFound
}
s := &series{
labels: cd.lset,
offsets: []ChunkOffset{
{Value: h.baseTimestamp, Offset: 0},
},
chunk: func(ref uint32) (chunks.Chunk, error) {
return cd.chunk, nil
},
}
return s, nil
}
// get retrieves the chunk with the hash and label set and creates
// a new one if it doesn't exist yet.
func (h *HeadBlock) get(hash uint64, lset Labels) *chunkDesc {
cds := h.descs[hash]
for _, cd := range cds {
if cd.lset.Equals(lset) {
return cd
}
}
// None of the given chunks was for the series, create a new one.
cd := &chunkDesc{
lset: lset,
chunk: chunks.NewXORChunk(int(math.MaxInt64)),
}
h.index.add(cd)
h.descs[hash] = append(cds, cd)
return cd
}
// append adds the sample to the headblock.
func (h *HeadBlock) append(hash uint64, lset Labels, ts int64, v float64) error {
if err := h.get(hash, lset).append(ts, v); err != nil {
return err
}
h.samples++
return nil
}
type blockStats struct {
chunks uint32
samples uint64
}
func (h *HeadBlock) stats() *blockStats {
return &blockStats{
chunks: uint32(h.index.numSeries()),
samples: h.samples,
}
}