4 files changed, 13 insertions, 12 deletions
diff --git a/format/pack/ingest/resolve.go b/format/pack/ingest/resolve.go
index c6336d18..6058a275 100644
--- a/format/pack/ingest/resolve.go
+++ b/format/pack/ingest/resolve.go
@@ -1,6 +1,7 @@
 package ingest
 
 import (
+	"bytes"
 	"errors"
 	"fmt"
 	"io"
@@ -45,7 +46,7 @@ func resolveAll(state *ingestState) error {
 		record.realType = ty
 		record.objectID = id
 		record.resolved = true
-		state.objectToRecord[id.String()] = idx
+		state.objectToRecord[id] = idx
 		state.baseCache.add(idx, ty, content)
 	}
 
@@ -87,7 +88,7 @@ func resolveRecord(state *ingestState, idx int, visiting map[int]struct{}) (obje
 		record.objectID = id
 		record.realType = ty
 		record.resolved = true
-		state.objectToRecord[id.String()] = idx
+		state.objectToRecord[id] = idx
 		state.baseCache.add(idx, ty, content)
 
 		return ty, content, nil
@@ -112,7 +113,7 @@ func resolveRecord(state *ingestState, idx int, visiting map[int]struct{}) (obje
 			return objecttype.TypeInvalid, nil, err
 		}
 	case objecttype.TypeRefDelta:
-		baseIdx, ok := state.objectToRecord[record.baseObject.String()]
+		baseIdx, ok := state.objectToRecord[record.baseObject]
 		if ok {
 			baseType, baseContent, err = resolveRecord(state, baseIdx, visiting)
 			if err != nil {
@@ -140,7 +141,7 @@ func resolveRecord(state *ingestState, idx int, visiting map[int]struct{}) (obje
 	record.objectID = id
 	record.realType = ty
 	record.resolved = true
-	state.objectToRecord[id.String()] = idx
+	state.objectToRecord[id] = idx
 	state.baseCache.add(idx, ty, content)
 
 	return ty, content, nil
@@ -258,21 +259,21 @@ func hashCanonicalObject(algo objectid.Algorithm, ty objecttype.Type, content []
 
 // unresolvedThinBaseIDs returns sorted unique unresolved ref base IDs.
 func unresolvedThinBaseIDs(state *ingestState) []objectid.ObjectID {
-	seen := make(map[string]objectid.ObjectID)
+	seen := make(map[objectid.ObjectID]struct{})
 	for _, idx := range state.unresolvedRefDeltas {
 		record := state.records[idx]
 		if record.packedType != objecttype.TypeRefDelta {
 			continue
 		}
-		seen[record.baseObject.String()] = record.baseObject
+		seen[record.baseObject] = struct{}{}
 	}
 
 	out := make([]objectid.ObjectID, 0, len(seen))
-	for _, id := range seen {
+	for id := range seen {
 		out = append(out, id)
 	}
 	slices.SortFunc(out, func(a, b objectid.ObjectID) int {
-		return slices.Compare(a.Bytes(), b.Bytes())
+		return bytes.Compare(a.RawBytes(), b.RawBytes())
 	})
 
 	return out
diff --git a/format/pack/ingest/state.go b/format/pack/ingest/state.go
index 7033a6f6..3fabe639 100644
--- a/format/pack/ingest/state.go
+++ b/format/pack/ingest/state.go
@@ -35,7 +35,7 @@ type ingestState struct {
 	refDeltas           []refDeltaRef
 	unresolvedRefDeltas []int
 	offsetToRecord      map[uint64]int
-	objectToRecord      map[string]int
+	objectToRecord      map[objectid.ObjectID]int
 
 	baseCache *deltaBaseCache
 	packHash  objectid.ObjectID
@@ -65,7 +65,7 @@ func newIngestState(
 		writeRev:       writeRev,
 		base:           base,
 		offsetToRecord: make(map[uint64]int),
-		objectToRecord: make(map[string]int),
+		objectToRecord: make(map[objectid.ObjectID]int),
 		baseCache:      newDeltaBaseCache(defaultDeltaBaseCacheMaxBytes),
 	}, nil
 }
diff --git a/format/pack/ingest/stream_scan.go b/format/pack/ingest/stream_scan.go
index 49290c0e..524467be 100644
--- a/format/pack/ingest/stream_scan.go
+++ b/format/pack/ingest/stream_scan.go
@@ -127,7 +127,7 @@ func scanOneEntry(state *ingestState, startOffset uint64) (uint64, error) {
 	state.records = append(state.records, record)
 	state.offsetToRecord[record.offset] = recordIdx
 	if record.resolved {
-		state.objectToRecord[record.objectID.String()] = recordIdx
+		state.objectToRecord[record.objectID] = recordIdx
 	}
 
 	switch record.packedType {
diff --git a/format/pack/ingest/thin_fix.go b/format/pack/ingest/thin_fix.go
index e605c3f2..436d5c88 100644
--- a/format/pack/ingest/thin_fix.go
+++ b/format/pack/ingest/thin_fix.go
@@ -98,7 +98,7 @@ func appendBaseObject(state *ingestState, id objectid.ObjectID, realType objectt
 	recordIdx := len(state.records)
 	state.records = append(state.records, record)
 	state.offsetToRecord[start] = recordIdx
-	state.objectToRecord[id.String()] = recordIdx
+	state.objectToRecord[id] = recordIdx
 	state.baseCache.add(recordIdx, realType, content)
 
 	return recordIdx, nil