switch sort impl to use interface

this improves perf in the case where we're not doing any sorting
as we avoid allocating memory and converting scores into
numeric terms

index_alias_impl_test.go

@@ -469,7 +469,7 @@ func TestIndexAliasMulti(t *testing.T) {
 				{
 					ID:    "a",
 					Score: 1.0,
-					Sort:  []string{string(score1)},
+					Sort:  []interface{}{string(score1)},
 				},
 			},
 			MaxScore: 1.0,
@@ -489,7 +489,7 @@ func TestIndexAliasMulti(t *testing.T) {
 				{
 					ID:    "b",
 					Score: 2.0,
-					Sort:  []string{string(score2)},
+					Sort:  []interface{}{string(score2)},
 				},
 			},
 			MaxScore: 2.0,
@@ -577,12 +577,12 @@ func TestIndexAliasMulti(t *testing.T) {
 			{
 				ID:    "b",
 				Score: 2.0,
-				Sort:  []string{string(score2)},
+				Sort:  []interface{}{string(score2)},
 			},
 			{
 				ID:    "a",
 				Score: 1.0,
-				Sort:  []string{string(score1)},
+				Sort:  []interface{}{string(score1)},
 			},
 		},
 		MaxScore: 2.0,
@@ -622,7 +622,7 @@ func TestMultiSearchNoError(t *testing.T) {
 				Index: "1",
 				ID:    "a",
 				Score: 1.0,
-				Sort:  []string{string(score1)},
+				Sort:  []interface{}{string(score1)},
 			},
 		},
 		MaxScore: 1.0,
@@ -639,7 +639,7 @@ func TestMultiSearchNoError(t *testing.T) {
 				Index: "2",
 				ID:    "b",
 				Score: 2.0,
-				Sort:  []string{string(score2)},
+				Sort:  []interface{}{string(score2)},
 			},
 		},
 		MaxScore: 2.0,
@@ -659,13 +659,13 @@ func TestMultiSearchNoError(t *testing.T) {
 				Index: "2",
 				ID:    "b",
 				Score: 2.0,
-				Sort:  []string{string(score2)},
+				Sort:  []interface{}{string(score2)},
 			},
 			{
 				Index: "1",
 				ID:    "a",
 				Score: 1.0,
-				Sort:  []string{string(score1)},
+				Sort:  []interface{}{string(score1)},
 			},
 		},
 		MaxScore: 2.0,
@@ -818,7 +818,7 @@ func TestMultiSearchTimeout(t *testing.T) {
 					Index: "1",
 					ID:    "a",
 					Score: 1.0,
-					Sort:  []string{string(score1)},
+					Sort:  []interface{}{string(score1)},
 				},
 			},
 			MaxScore: 1.0,
@@ -842,7 +842,7 @@ func TestMultiSearchTimeout(t *testing.T) {
 					Index: "2",
 					ID:    "b",
 					Score: 2.0,
-					Sort:  []string{string(score2)},
+					Sort:  []interface{}{string(score2)},
 				},
 			},
 			MaxScore: 2.0,
@@ -944,7 +944,7 @@ func TestMultiSearchTimeoutPartial(t *testing.T) {
 					Index: "1",
 					ID:    "a",
 					Score: 1.0,
-					Sort:  []string{string(score1)},
+					Sort:  []interface{}{string(score1)},
 				},
 			},
 			MaxScore: 1.0,
@@ -964,7 +964,7 @@ func TestMultiSearchTimeoutPartial(t *testing.T) {
 					Index: "2",
 					ID:    "b",
 					Score: 2.0,
-					Sort:  []string{string(score2)},
+					Sort:  []interface{}{string(score2)},
 				},
 			},
 			MaxScore: 2.0,
@@ -989,7 +989,7 @@ func TestMultiSearchTimeoutPartial(t *testing.T) {
 					Index: "3",
 					ID:    "c",
 					Score: 3.0,
-					Sort:  []string{string(score3)},
+					Sort:  []interface{}{string(score3)},
 				},
 			},
 			MaxScore: 3.0,
@@ -1016,13 +1016,13 @@ func TestMultiSearchTimeoutPartial(t *testing.T) {
 				Index: "2",
 				ID:    "b",
 				Score: 2.0,
-				Sort:  []string{string(score2)},
+				Sort:  []interface{}{string(score2)},
 			},
 			{
 				Index: "1",
 				ID:    "a",
 				Score: 1.0,
-				Sort:  []string{string(score1)},
+				Sort:  []interface{}{string(score1)},
 			},
 		},
 		MaxScore: 2.0,
@@ -1058,7 +1058,7 @@ func TestIndexAliasMultipleLayer(t *testing.T) {
 					Index: "1",
 					ID:    "a",
 					Score: 1.0,
-					Sort:  []string{string(score1)},
+					Sort:  []interface{}{string(score1)},
 				},
 			},
 			MaxScore: 1.0,
@@ -1082,7 +1082,7 @@ func TestIndexAliasMultipleLayer(t *testing.T) {
 					Index: "2",
 					ID:    "b",
 					Score: 2.0,
-					Sort:  []string{string(score2)},
+					Sort:  []interface{}{string(score2)},
 				},
 			},
 			MaxScore: 2.0,
@@ -1107,7 +1107,7 @@ func TestIndexAliasMultipleLayer(t *testing.T) {
 					Index: "3",
 					ID:    "c",
 					Score: 3.0,
-					Sort:  []string{string(score3)},
+					Sort:  []interface{}{string(score3)},
 				},
 			},
 			MaxScore: 3.0,
@@ -1128,7 +1128,7 @@ func TestIndexAliasMultipleLayer(t *testing.T) {
 					Index: "4",
 					ID:    "d",
 					Score: 4.0,
-					Sort:  []string{string(score4)},
+					Sort:  []interface{}{string(score4)},
 				},
 			},
 			MaxScore: 4.0,
@@ -1162,13 +1162,13 @@ func TestIndexAliasMultipleLayer(t *testing.T) {
 				Index: "4",
 				ID:    "d",
 				Score: 4.0,
-				Sort:  []string{string(score4)},
+				Sort:  []interface{}{string(score4)},
 			},
 			{
 				Index: "1",
 				ID:    "a",
 				Score: 1.0,
-				Sort:  []string{string(score1)},
+				Sort:  []interface{}{string(score1)},
 			},
 		},
 		MaxScore: 4.0,
@@ -1198,13 +1198,13 @@ func TestMultiSearchCustomSort(t *testing.T) {
 				Index: "1",
 				ID:    "a",
 				Score: 1.0,
-				Sort:  []string{"albert"},
+				Sort:  []interface{}{"albert"},
 			},
 			{
 				Index: "1",
 				ID:    "b",
 				Score: 2.0,
-				Sort:  []string{"crown"},
+				Sort:  []interface{}{"crown"},
 			},
 		},
 		MaxScore: 2.0,
@@ -1221,13 +1221,13 @@ func TestMultiSearchCustomSort(t *testing.T) {
 				Index: "2",
 				ID:    "c",
 				Score: 2.5,
-				Sort:  []string{"frank"},
+				Sort:  []interface{}{"frank"},
 			},
 			{
 				Index: "2",
 				ID:    "d",
 				Score: 3.0,
-				Sort:  []string{"zombie"},
+				Sort:  []interface{}{"zombie"},
 			},
 		},
 		MaxScore: 3.0,
@@ -1248,25 +1248,25 @@ func TestMultiSearchCustomSort(t *testing.T) {
 				Index: "1",
 				ID:    "a",
 				Score: 1.0,
-				Sort:  []string{"albert"},
+				Sort:  []interface{}{"albert"},
 			},
 			{
 				Index: "1",
 				ID:    "b",
 				Score: 2.0,
-				Sort:  []string{"crown"},
+				Sort:  []interface{}{"crown"},
 			},
 			{
 				Index: "2",
 				ID:    "c",
 				Score: 2.5,
-				Sort:  []string{"frank"},
+				Sort:  []interface{}{"frank"},
 			},
 			{
 				Index: "2",
 				ID:    "d",
 				Score: 3.0,
-				Sort:  []string{"zombie"},
+				Sort:  []interface{}{"zombie"},
 			},
 		},
 		MaxScore: 3.0,

search/collectors/bench_test.go

@@ -13,12 +13,13 @@ import (
 type createCollector func() search.Collector
 
 func benchHelper(numOfMatches int, cc createCollector, b *testing.B) {
+	dp := search.NewDocumentMatchPool(numOfMatches, 1)
 	matches := make([]*search.DocumentMatch, 0, numOfMatches)
 	for i := 0; i < numOfMatches; i++ {
-		matches = append(matches, &search.DocumentMatch{
-			IndexInternalID: index.IndexInternalID(strconv.Itoa(i)),
-			Score:           rand.Float64(),
-		})
+		match := dp.Get()
+		match.IndexInternalID = index.IndexInternalID(strconv.Itoa(i))
+		match.Score = rand.Float64()
+		matches = append(matches, match)
 	}
 
 	b.ResetTimer()

search/collectors/collector_heap.go

@@ -28,6 +28,9 @@ type HeapCollector struct {
 	results       search.DocumentMatchCollection
 	facetsBuilder *search.FacetsBuilder
 
+	needDocIds   bool
+	neededFields []string
+
 	lowestMatchOutsideResults *search.DocumentMatch
 }
 
@@ -35,7 +38,15 @@ var COLLECT_CHECK_DONE_EVERY = uint64(1024)
 
 func NewHeapCollector(size int, skip int, sort search.SortOrder) *HeapCollector {
 	hc := &HeapCollector{size: size, skip: skip, sort: sort}
+	hc.results = make(search.DocumentMatchCollection, 0, size+skip)
 	heap.Init(hc)
+
+	// these lookups traverse an interface, so do once up-front
+	if sort.RequiresDocID() {
+		hc.needDocIds = true
+	}
+	hc.neededFields = sort.RequiredFields()
+
 	return hc
 }
 
@@ -49,7 +60,7 @@ func (hc *HeapCollector) Collect(ctx context.Context, searcher search.Searcher,
 	// plus possibly one extra for the highestMatchOutsideResults
 	// plus the amount required by the searcher tree
 	searchContext := &search.SearchContext{
-		DocumentMatchPool: search.NewDocumentMatchPool(hc.size + hc.skip + 1 + searcher.DocumentMatchPoolSize()),
+		DocumentMatchPool: search.NewDocumentMatchPool(hc.size+hc.skip+1+searcher.DocumentMatchPoolSize(), len(hc.sort)),
 	}
 
 	select {
@@ -105,7 +116,7 @@ func (hc *HeapCollector) collectSingle(ctx *search.SearchContext, reader index.I
 
 	var err error
 	// see if we need to load ID (at this early stage, for example to sort on it)
-	if hc.sort.RequiresDocID() {
+	if hc.needDocIds {
 		d.ID, err = reader.FinalizeDocID(d.IndexInternalID)
 		if err != nil {
 			return err
@@ -113,9 +124,9 @@ func (hc *HeapCollector) collectSingle(ctx *search.SearchContext, reader index.I
 	}
 
 	// see if we need to load the stored fields
-	if len(hc.sort.RequiredFields()) > 0 {
+	if len(hc.neededFields) > 0 {
 		// find out which fields haven't been loaded yet
-		fieldsToLoad := d.CachedFieldTerms.FieldsNotYetCached(hc.sort.RequiredFields())
+		fieldsToLoad := d.CachedFieldTerms.FieldsNotYetCached(hc.neededFields)
 		// look them up
 		fieldTerms, err := reader.DocumentFieldTerms(d.IndexInternalID, fieldsToLoad)
 		if err != nil {
@@ -129,7 +140,7 @@ func (hc *HeapCollector) collectSingle(ctx *search.SearchContext, reader index.I
 	}
 
 	// compute this hits sort value
-	d.Sort = hc.sort.Value(d)
+	hc.sort.Value(d)
 
 	// optimization, we track lowest sorting hit already removed from heap
 	// with this one comparision, we can avoid all heap operations if

search/pool.go

@@ -31,12 +31,13 @@ func defaultDocumentMatchPoolTooSmall(p *DocumentMatchPool) *DocumentMatch {
 // NewDocumentMatchPool will build a DocumentMatchPool with memory
 // pre-allocated to accomodate the requested number of DocumentMatch
 // instances
-func NewDocumentMatchPool(size int) *DocumentMatchPool {
+func NewDocumentMatchPool(size, sortsize int) *DocumentMatchPool {
 	avail := make(DocumentMatchCollection, 0, size)
 	// pre-allocate the expected number of instances
 	startBlock := make([]DocumentMatch, size)
 	// make these initial instances available
 	for i := range startBlock {
+		startBlock[i].Sort = make([]interface{}, 0, sortsize)
 		avail = append(avail, &startBlock[i])
 	}
 	return &DocumentMatchPool{

search/pool_test.go

@@ -16,7 +16,7 @@ func TestDocumentMatchPool(t *testing.T) {
 	tooManyCalled := false
 
 	// create a pool
-	dmp := NewDocumentMatchPool(10)
+	dmp := NewDocumentMatchPool(10, 0)
 	dmp.TooSmall = func(inner *DocumentMatchPool) *DocumentMatch {
 		tooManyCalled = true
 		return &DocumentMatch{}

search/scorers/scorer_constant_test.go

@@ -47,13 +47,14 @@ func TestConstantScorer(t *testing.T) {
 					Value:   1.0,
 					Message: "ConstantScore()",
 				},
+				Sort: []interface{}{},
 			},
 		},
 	}
 
 	for _, test := range tests {
 		ctx := &search.SearchContext{
-			DocumentMatchPool: search.NewDocumentMatchPool(1),
+			DocumentMatchPool: search.NewDocumentMatchPool(1, 0),
 		}
 		actual := scorer.Score(ctx, test.termMatch.ID)
 
@@ -82,6 +83,7 @@ func TestConstantScorerWithQueryNorm(t *testing.T) {
 			result: &search.DocumentMatch{
 				IndexInternalID: index.IndexInternalID("one"),
 				Score:           2.0,
+				Sort:            []interface{}{},
 				Expl: &search.Explanation{
 					Value:   2.0,
 					Message: "weight(^1.000000), product of:",
@@ -112,7 +114,7 @@ func TestConstantScorerWithQueryNorm(t *testing.T) {
 
 	for _, test := range tests {
 		ctx := &search.SearchContext{
-			DocumentMatchPool: search.NewDocumentMatchPool(1),
+			DocumentMatchPool: search.NewDocumentMatchPool(1, 0),
 		}
 		actual := scorer.Score(ctx, test.termMatch.ID)
 

search/scorers/scorer_term_test.go

@@ -50,6 +50,7 @@ func TestTermScorer(t *testing.T) {
 			result: &search.DocumentMatch{
 				IndexInternalID: index.IndexInternalID("one"),
 				Score:           math.Sqrt(1.0) * idf,
+				Sort:            []interface{}{},
 				Expl: &search.Explanation{
 					Value:   math.Sqrt(1.0) * idf,
 					Message: "fieldWeight(desc:beer in one), product of:",
@@ -91,6 +92,7 @@ func TestTermScorer(t *testing.T) {
 			result: &search.DocumentMatch{
 				IndexInternalID: index.IndexInternalID("one"),
 				Score:           math.Sqrt(1.0) * idf,
+				Sort:            []interface{}{},
 				Expl: &search.Explanation{
 					Value:   math.Sqrt(1.0) * idf,
 					Message: "fieldWeight(desc:beer in one), product of:",
@@ -121,6 +123,7 @@ func TestTermScorer(t *testing.T) {
 			result: &search.DocumentMatch{
 				IndexInternalID: index.IndexInternalID("one"),
 				Score:           math.Sqrt(65) * idf,
+				Sort:            []interface{}{},
 				Expl: &search.Explanation{
 					Value:   math.Sqrt(65) * idf,
 					Message: "fieldWeight(desc:beer in one), product of:",
@@ -145,7 +148,7 @@ func TestTermScorer(t *testing.T) {
 
 	for _, test := range tests {
 		ctx := &search.SearchContext{
-			DocumentMatchPool: search.NewDocumentMatchPool(1),
+			DocumentMatchPool: search.NewDocumentMatchPool(1, 0),
 		}
 		actual := scorer.Score(ctx, test.termMatch)
 
@@ -187,6 +190,7 @@ func TestTermScorerWithQueryNorm(t *testing.T) {
 			result: &search.DocumentMatch{
 				IndexInternalID: index.IndexInternalID("one"),
 				Score:           math.Sqrt(1.0) * idf * 3.0 * idf * 2.0,
+				Sort:            []interface{}{},
 				Expl: &search.Explanation{
 					Value:   math.Sqrt(1.0) * idf * 3.0 * idf * 2.0,
 					Message: "weight(desc:beer^3.000000 in one), product of:",
@@ -235,7 +239,7 @@ func TestTermScorerWithQueryNorm(t *testing.T) {
 
 	for _, test := range tests {
 		ctx := &search.SearchContext{
-			DocumentMatchPool: search.NewDocumentMatchPool(1),
+			DocumentMatchPool: search.NewDocumentMatchPool(1, 0),
 		}
 		actual := scorer.Score(ctx, test.termMatch)
 

search/search.go

@@ -65,7 +65,7 @@ type DocumentMatch struct {
 	Expl            *Explanation          `json:"explanation,omitempty"`
 	Locations       FieldTermLocationMap  `json:"locations,omitempty"`
 	Fragments       FieldFragmentMap      `json:"fragments,omitempty"`
-	Sort            []string              `json:"sort,omitempty"`
+	Sort            []interface{}         `json:"sort,omitempty"`
 
 	// Fields contains the values for document fields listed in
 	// SearchRequest.Fields. Text fields are returned as strings, numeric
@@ -107,11 +107,15 @@ func (dm *DocumentMatch) AddFieldValue(name string, value interface{}) {
 // Reset allows an already allocated DocumentMatch to be reused
 func (dm *DocumentMatch) Reset() *DocumentMatch {
 	// remember the []byte used for the IndexInternalID
-	indexInternalId := dm.IndexInternalID
+	indexInternalID := dm.IndexInternalID
+	// remember the []interface{} used for sort
+	sort := dm.Sort
 	// idiom to copy over from empty DocumentMatch (0 allocations)
 	*dm = DocumentMatch{}
 	// reuse the []byte already allocated (and reset len to 0)
-	dm.IndexInternalID = indexInternalId[:0]
+	dm.IndexInternalID = indexInternalID[:0]
+	// reuse the []interface{} already allocated (and reset len to 0)
+	dm.Sort = sort[:0]
 	return dm
 }
 

search/searchers/search_boolean_test.go

@@ -344,7 +344,7 @@ func TestBooleanSearch(t *testing.T) {
 		}()
 
 		ctx := &search.SearchContext{
-			DocumentMatchPool: search.NewDocumentMatchPool(test.searcher.DocumentMatchPoolSize()),
+			DocumentMatchPool: search.NewDocumentMatchPool(test.searcher.DocumentMatchPoolSize(), 0),
 		}
 		next, err := test.searcher.Next(ctx)
 		i := 0

search/searchers/search_conjunction_test.go

@@ -189,7 +189,7 @@ func TestConjunctionSearch(t *testing.T) {
 		}()
 
 		ctx := &search.SearchContext{
-			DocumentMatchPool: search.NewDocumentMatchPool(10),
+			DocumentMatchPool: search.NewDocumentMatchPool(10, 0),
 		}
 		next, err := test.searcher.Next(ctx)
 		i := 0

search/searchers/search_disjunction_test.go

@@ -110,7 +110,7 @@ func TestDisjunctionSearch(t *testing.T) {
 		}()
 
 		ctx := &search.SearchContext{
-			DocumentMatchPool: search.NewDocumentMatchPool(test.searcher.DocumentMatchPoolSize()),
+			DocumentMatchPool: search.NewDocumentMatchPool(test.searcher.DocumentMatchPoolSize(), 0),
 		}
 		next, err := test.searcher.Next(ctx)
 		i := 0
@@ -164,7 +164,7 @@ func TestDisjunctionAdvance(t *testing.T) {
 	}
 
 	ctx := &search.SearchContext{
-		DocumentMatchPool: search.NewDocumentMatchPool(martyOrDustinSearcher.DocumentMatchPoolSize()),
+		DocumentMatchPool: search.NewDocumentMatchPool(martyOrDustinSearcher.DocumentMatchPoolSize(), 0),
 	}
 	match, err := martyOrDustinSearcher.Advance(ctx, index.IndexInternalID("3"))
 	if err != nil {

search/searchers/search_docid_test.go

@@ -64,7 +64,7 @@ func testDocIDSearcher(t *testing.T, indexed, searched, wanted []string) {
 	}()
 
 	ctx := &search.SearchContext{
-		DocumentMatchPool: search.NewDocumentMatchPool(searcher.DocumentMatchPoolSize()),
+		DocumentMatchPool: search.NewDocumentMatchPool(searcher.DocumentMatchPoolSize(), 0),
 	}
 
 	// Check the sequence

search/searchers/search_fuzzy_test.go

@@ -107,7 +107,7 @@ func TestFuzzySearch(t *testing.T) {
 		}()
 
 		ctx := &search.SearchContext{
-			DocumentMatchPool: search.NewDocumentMatchPool(test.searcher.DocumentMatchPoolSize()),
+			DocumentMatchPool: search.NewDocumentMatchPool(test.searcher.DocumentMatchPoolSize(), 0),
 		}
 		next, err := test.searcher.Next(ctx)
 		i := 0

search/searchers/search_match_all_test.go

@@ -111,7 +111,7 @@ func TestMatchAllSearch(t *testing.T) {
 		}()
 
 		ctx := &search.SearchContext{
-			DocumentMatchPool: search.NewDocumentMatchPool(test.searcher.DocumentMatchPoolSize()),
+			DocumentMatchPool: search.NewDocumentMatchPool(test.searcher.DocumentMatchPoolSize(), 0),
 		}
 		next, err := test.searcher.Next(ctx)
 		i := 0

search/searchers/search_match_none_test.go

@@ -52,7 +52,7 @@ func TestMatchNoneSearch(t *testing.T) {
 		}()
 
 		ctx := &search.SearchContext{
-			DocumentMatchPool: search.NewDocumentMatchPool(test.searcher.DocumentMatchPoolSize()),
+			DocumentMatchPool: search.NewDocumentMatchPool(test.searcher.DocumentMatchPoolSize(), 0),
 		}
 		next, err := test.searcher.Next(ctx)
 		i := 0

search/searchers/search_phrase_test.go

@@ -70,7 +70,7 @@ func TestPhraseSearch(t *testing.T) {
 		}()
 
 		ctx := &search.SearchContext{
-			DocumentMatchPool: search.NewDocumentMatchPool(test.searcher.DocumentMatchPoolSize()),
+			DocumentMatchPool: search.NewDocumentMatchPool(test.searcher.DocumentMatchPoolSize(), 0),
 		}
 		next, err := test.searcher.Next(ctx)
 		i := 0

search/searchers/search_regexp_test.go

@@ -87,7 +87,7 @@ func TestRegexpSearch(t *testing.T) {
 		}()
 
 		ctx := &search.SearchContext{
-			DocumentMatchPool: search.NewDocumentMatchPool(test.searcher.DocumentMatchPoolSize()),
+			DocumentMatchPool: search.NewDocumentMatchPool(test.searcher.DocumentMatchPoolSize(), 0),
 		}
 		next, err := test.searcher.Next(ctx)
 		i := 0

search/searchers/search_term_test.go

@@ -165,7 +165,7 @@ func TestTermSearcher(t *testing.T) {
 	}
 
 	ctx := &search.SearchContext{
-		DocumentMatchPool: search.NewDocumentMatchPool(1),
+		DocumentMatchPool: search.NewDocumentMatchPool(1, 0),
 	}
 	docMatch, err := searcher.Next(ctx)
 	if err != nil {

search/sort.go

@@ -22,7 +22,7 @@ var HighTerm = strings.Repeat(string([]byte{0xff}), 10)
 var LowTerm = string([]byte{0x00})
 
 type SearchSort interface {
-	Value(a *DocumentMatch) string
+	Value(a *DocumentMatch) interface{}
 	Descending() bool
 
 	RequiresDocID() bool
@@ -160,27 +160,55 @@ func ParseSortOrderJSON(in []json.RawMessage) (SortOrder, error) {
 
 type SortOrder []SearchSort
 
-func (so SortOrder) Value(doc *DocumentMatch) []string {
-	rv := make([]string, len(so))
-	for i, soi := range so {
-		rv[i] = soi.Value(doc)
+func (so SortOrder) Value(doc *DocumentMatch) {
+	for _, soi := range so {
+		doc.Sort = append(doc.Sort, soi.Value(doc))
 	}
-	return rv
 }
 
+// Compare will compare two document matches using the specified sort order
+// if both are numbers, we avoid converting back to term
 func (so SortOrder) Compare(i, j *DocumentMatch) int {
 	// compare the documents on all search sorts until a differences is found
 	for x, soi := range so {
 		iVal := i.Sort[x]
 		jVal := j.Sort[x]
-		c := strings.Compare(iVal, jVal)
+		c := 0
+		switch iVal := iVal.(type) {
+		case string:
+			switch jVal := jVal.(type) {
+			case string:
+				// both string
+				c = strings.Compare(iVal, jVal)
+			case float64:
+				// i is string, j is number, i sorts higher
+				ji := numeric_util.Float64ToInt64(jVal)
+				jt, _ := numeric_util.NewPrefixCodedInt64(ji, 0)
+				c = strings.Compare(iVal, string(jt))
+			}
+		case float64:
+			switch jVal := jVal.(type) {
+			case string:
+				// i is number, j is string
+				ii := numeric_util.Float64ToInt64(iVal)
+				it, _ := numeric_util.NewPrefixCodedInt64(ii, 0)
+				c = strings.Compare(string(it), jVal)
+			case float64:
+				// numeric comparison
+				if iVal < jVal {
+					c = -1
+				} else if iVal > jVal {
+					c = 1
+				}
+			}
+		}
+
 		if c == 0 {
 			continue
 		}
 		if soi.Descending() {
 			c = -c
 		}
-		//c := soi.Compare(i, j)
 		return c
 	}
 	// if they are the same at this point, impose order based on index natural sort order
@@ -273,10 +301,23 @@ type SortField struct {
 }
 
 // Value returns the sort value of the DocumentMatch
-func (s *SortField) Value(i *DocumentMatch) string {
+func (s *SortField) Value(i *DocumentMatch) interface{} {
 	iTerms := i.CachedFieldTerms[s.Field]
 	iTerms = s.filterTermsByType(iTerms)
 	iTerm := s.filterTermsByMode(iTerms)
+	if s.Type == SortFieldAsNumber || s.Type == SortFieldAsDate {
+		// explicitly asked for numeric sort
+		rv, _ := numeric_util.PrefixCoded(iTerm).Int64()
+		return rv
+	} else if s.Type == SortFieldAuto {
+		// asked for auto, looks like a number
+		valid, shift := numeric_util.ValidPrefixCodedTerm(iTerm)
+		if valid && shift == 0 {
+			ri, _ := numeric_util.PrefixCoded(iTerm).Int64()
+			rv := numeric_util.Int64ToFloat64(ri)
+			return rv
+		}
+	}
 	return iTerm
 }
 
@@ -406,7 +447,7 @@ type SortDocID struct {
 }
 
 // Value returns the sort value of the DocumentMatch
-func (s *SortDocID) Value(i *DocumentMatch) string {
+func (s *SortDocID) Value(i *DocumentMatch) interface{} {
 	return i.ID
 }
 
@@ -437,10 +478,8 @@ type SortScore struct {
 }
 
 // Value returns the sort value of the DocumentMatch
-func (s *SortScore) Value(i *DocumentMatch) string {
-	scoreInt := numeric_util.Float64ToInt64(i.Score)
-	prefixCodedScore, _ := numeric_util.NewPrefixCodedInt64(scoreInt, 0)
-	return string(prefixCodedScore)
+func (s *SortScore) Value(i *DocumentMatch) interface{} {
+	return i.Score
 }
 
 // Descending determines the order of the sort