TSDB: Remove code for querying OOO-head only

Just query via `HeadAndOOOQuerier`, which will skip series where no
in-order chunks are in range.

Now we don't need `OOORangeHead`.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>

tsdb/db.go

@@ -2041,8 +2041,9 @@ func (db *DB) Querier(mint, maxt int64) (_ storage.Querier, err error) {
 		}
 	}()
 
+	overlapsOOO := overlapsClosedInterval(mint, maxt, db.head.MinOOOTime(), db.head.MaxOOOTime())
 	var headQuerier storage.Querier
-	if maxt >= db.head.MinTime() {
+	if maxt >= db.head.MinTime() || overlapsOOO {
 		rh := NewRangeHead(db.head, mint, maxt)
 		var err error
 		headQuerier, err = db.blockQuerierFunc(rh, mint, maxt)
@@ -2069,22 +2070,10 @@ func (db *DB) Querier(mint, maxt int64) (_ storage.Querier, err error) {
 		}
 	}
 
-	if headQuerier != nil {
+	if overlapsOOO {
-		if overlapsClosedInterval(mint, maxt, db.head.MinOOOTime(), db.head.MaxOOOTime()) {
+		// We need to fetch from in-order and out-of-order chunks: wrap the headQuerier.
-			// We need to fetch from in-order and out-of-order chunks: wrap the headQuerier.
+		isoState := db.head.oooIso.TrackReadAfter(db.lastGarbageCollectedMmapRef)
-			isoState := db.head.oooIso.TrackReadAfter(db.lastGarbageCollectedMmapRef)
+		headQuerier = NewHeadAndOOOQuerier(mint, maxt, db.head, isoState, headQuerier)
-			headQuerier = NewHeadAndOOOQuerier(mint, maxt, db.head, isoState, headQuerier)
-		}
-	} else if overlapsClosedInterval(mint, maxt, db.head.MinOOOTime(), db.head.MaxOOOTime()) {
-		rh := NewOOORangeHead(db.head, mint, maxt, db.lastGarbageCollectedMmapRef)
-		var err error
-		headQuerier, err = db.blockQuerierFunc(rh, mint, maxt)
-		if err != nil {
-			// If BlockQuerierFunc() failed, make sure to clean up the pending read created by NewOOORangeHead.
-			rh.isoState.Close()
-
-			return nil, fmt.Errorf("open block querier for ooo head %s: %w", rh, err)
-		}
 	}
 
 	if headQuerier != nil {
@@ -2128,8 +2117,9 @@ func (db *DB) blockChunkQuerierForRange(mint, maxt int64) (_ []storage.ChunkQuer
 		}
 	}()
 
+	overlapsOOO := overlapsClosedInterval(mint, maxt, db.head.MinOOOTime(), db.head.MaxOOOTime())
 	var headQuerier storage.ChunkQuerier
-	if maxt >= db.head.MinTime() {
+	if maxt >= db.head.MinTime() || overlapsOOO {
 		rh := NewRangeHead(db.head, mint, maxt)
 		headQuerier, err = db.blockChunkQuerierFunc(rh, mint, maxt)
 		if err != nil {
@@ -2155,21 +2145,10 @@ func (db *DB) blockChunkQuerierForRange(mint, maxt int64) (_ []storage.ChunkQuer
 		}
 	}
 
-	if headQuerier != nil {
+	if overlapsOOO {
-		if overlapsClosedInterval(mint, maxt, db.head.MinOOOTime(), db.head.MaxOOOTime()) {
+		// We need to fetch from in-order and out-of-order chunks: wrap the headQuerier.
-			// We need to fetch from in-order and out-of-order chunks: wrap the headQuerier.
+		isoState := db.head.oooIso.TrackReadAfter(db.lastGarbageCollectedMmapRef)
-			isoState := db.head.oooIso.TrackReadAfter(db.lastGarbageCollectedMmapRef)
+		headQuerier = NewHeadAndOOOChunkQuerier(mint, maxt, db.head, isoState, headQuerier)
-			headQuerier = NewHeadAndOOOChunkQuerier(mint, maxt, db.head, isoState, headQuerier)
-		}
-	} else if overlapsClosedInterval(mint, maxt, db.head.MinOOOTime(), db.head.MaxOOOTime()) {
-		rh := NewOOORangeHead(db.head, mint, maxt, db.lastGarbageCollectedMmapRef)
-		headQuerier, err = db.blockChunkQuerierFunc(rh, mint, maxt)
-		if err != nil {
-			// If NewBlockQuerier() failed, make sure to clean up the pending read created by NewOOORangeHead.
-			rh.isoState.Close()
-
-			return nil, fmt.Errorf("open block chunk querier for ooo head %s: %w", rh, err)
-		}
 	}
 
 	if headQuerier != nil {

tsdb/ooo_head.go

@@ -14,16 +14,10 @@
 package tsdb
 
 import (
-	"fmt"
 	"sort"
 
 	"github.com/prometheus/prometheus/model/histogram"
 	"github.com/prometheus/prometheus/tsdb/chunkenc"
-
-	"github.com/oklog/ulid"
-
-	"github.com/prometheus/prometheus/tsdb/chunks"
-	"github.com/prometheus/prometheus/tsdb/tombstones"
 )
 
 // OOOChunk maintains samples in time-ascending order.
@@ -171,75 +165,3 @@ func (o *OOOChunk) ToEncodedChunks(mint, maxt int64) (chks []memChunk, err error
 	}
 	return chks, nil
 }
-
-var _ BlockReader = &OOORangeHead{}
-
-// OOORangeHead allows querying Head out of order samples via BlockReader
-// interface implementation.
-type OOORangeHead struct {
-	head *Head
-	// mint and maxt are tracked because when a query is handled we only want
-	// the timerange of the query and having preexisting pointers to the first
-	// and last timestamp help with that.
-	mint, maxt int64
-
-	isoState *oooIsolationState
-}
-
-func NewOOORangeHead(head *Head, mint, maxt int64, minRef chunks.ChunkDiskMapperRef) *OOORangeHead {
-	isoState := head.oooIso.TrackReadAfter(minRef)
-
-	return &OOORangeHead{
-		head:     head,
-		mint:     mint,
-		maxt:     maxt,
-		isoState: isoState,
-	}
-}
-
-func (oh *OOORangeHead) Index() (IndexReader, error) {
-	return NewOOOHeadIndexReader(oh.head, oh.mint, oh.maxt, oh.isoState.minRef), nil
-}
-
-func (oh *OOORangeHead) Chunks() (ChunkReader, error) {
-	return NewOOOHeadChunkReader(oh.head, oh.mint, oh.maxt, oh.isoState, 0), nil
-}
-
-func (oh *OOORangeHead) Tombstones() (tombstones.Reader, error) {
-	// As stated in the design doc https://docs.google.com/document/d/1Kppm7qL9C-BJB1j6yb6-9ObG3AbdZnFUBYPNNWwDBYM/edit?usp=sharing
-	// Tombstones are not supported for out of order metrics.
-	return tombstones.NewMemTombstones(), nil
-}
-
-var oooRangeHeadULID = ulid.MustParse("0000000000XXXX000RANGEHEAD")
-
-func (oh *OOORangeHead) Meta() BlockMeta {
-	return BlockMeta{
-		MinTime: oh.mint,
-		MaxTime: oh.maxt,
-		ULID:    oooRangeHeadULID,
-		Stats: BlockStats{
-			NumSeries: oh.head.NumSeries(),
-		},
-	}
-}
-
-// Size returns the size taken by the Head block.
-func (oh *OOORangeHead) Size() int64 {
-	return oh.head.Size()
-}
-
-// String returns an human readable representation of the out of order range
-// head. It's important to keep this function in order to avoid the struct dump
-// when the head is stringified in errors or logs.
-func (oh *OOORangeHead) String() string {
-	return fmt.Sprintf("ooo range head (mint: %d, maxt: %d)", oh.MinTime(), oh.MaxTime())
-}
-
-func (oh *OOORangeHead) MinTime() int64 {
-	return oh.mint
-}
-
-func (oh *OOORangeHead) MaxTime() int64 {
-	return oh.maxt
-}