diff --git a/posting/list.go b/posting/list.go
index f5a47f677e7..b2a509432ae 100644
--- a/posting/list.go
+++ b/posting/list.go
@@ -19,10 +19,10 @@ package posting
 import (
 	"bytes"
 	"context"
-	"fmt"
 	"log"
 	"math"
 	"sort"
+	"sync"
 
 	"github.com/dgryski/go-farm"
 
@@ -279,7 +279,8 @@ func NewPosting(t *pb.DirectedEdge) *pb.Posting {
 		postingType = pb.Posting_REF
 	}
 
-	return &pb.Posting{
+	p := postingPool.Get().(*pb.Posting)
+	*p = pb.Posting{
 		Uid:         t.ValueId,
 		Value:       t.Value,
 		ValType:     t.ValueType,
@@ -289,6 +290,7 @@ func NewPosting(t *pb.DirectedEdge) *pb.Posting {
 		Op:          op,
 		Facets:      t.Facets,
 	}
+	return p
 }
 
 func hasDeleteAll(mpost *pb.Posting) bool {
@@ -393,6 +395,26 @@ func (l *List) addMutation(ctx context.Context, txn *Txn, t *pb.DirectedEdge) er
 	return l.addMutationInternal(ctx, txn, t)
 }
 
+var postingPool = &sync.Pool{
+	New: func() interface{} {
+		return &pb.Posting{}
+	},
+}
+
+func (l *List) release() {
+	fromList := func(list *pb.PostingList) {
+		for _, p := range list.GetPostings() {
+			postingPool.Put(p)
+		}
+	}
+	fromList(l.plist)
+	for _, plist := range l.mutationMap {
+		fromList(plist)
+	}
+	l.plist = nil
+	l.mutationMap = nil
+}
+
 func (l *List) addMutationInternal(ctx context.Context, txn *Txn, t *pb.DirectedEdge) error {
 	l.AssertLock()
 
@@ -400,8 +422,11 @@ func (l *List) addMutationInternal(ctx context.Context, txn *Txn, t *pb.Directed
 		return y.ErrConflict
 	}
 
-	getKey := func(key []byte, uid uint64) string {
-		return fmt.Sprintf("%s|%d", key, uid)
+	getKey := func(key []byte, uid uint64) uint64 {
+		// Instead of creating a string first and then doing a fingerprint, let's do a fingerprint
+		// here to save memory allocations.
+		// Not entirely sure about effect on collision chances due to this simple XOR with uid.
+		return farm.Fingerprint64(key) ^ uid
 	}
 
 	mpost := NewPosting(t)
@@ -415,7 +440,7 @@ func (l *List) addMutationInternal(ctx context.Context, txn *Txn, t *pb.Directed
 	// We ensure that commit marks are applied to posting lists in the right
 	// order. We can do so by proposing them in the same order as received by the Oracle delta
 	// stream from Zero, instead of in goroutines.
-	var conflictKey string
+	var conflictKey uint64
 	pk := x.Parse(l.key)
 	switch {
 	case schema.State().HasUpsert(t.Attr):
diff --git a/posting/lists.go b/posting/lists.go
index cc803e25e5e..53364f25d5a 100644
--- a/posting/lists.go
+++ b/posting/lists.go
@@ -281,6 +281,7 @@ func (lc *LocalCache) UpdateDeltasAndDiscardLists() {
 			lc.deltas[key] = data
 		}
 		lc.maxVersions[key] = pl.maxVersion()
+		pl.release()
 	}
 	lc.plists = make(map[string]*List)
 }
diff --git a/posting/mvcc.go b/posting/mvcc.go
index 14a32b3c706..6f46e8b57e7 100644
--- a/posting/mvcc.go
+++ b/posting/mvcc.go
@@ -27,7 +27,6 @@ import (
 	"github.com/dgraph-io/dgo/protos/api"
 	"github.com/dgraph-io/dgraph/protos/pb"
 	"github.com/dgraph-io/dgraph/x"
-	farm "github.com/dgryski/go-farm"
 	"github.com/pkg/errors"
 )
 
@@ -44,13 +43,13 @@ func (txn *Txn) ShouldAbort() bool {
 	return atomic.LoadUint32(&txn.shouldAbort) > 0
 }
 
-func (txn *Txn) addConflictKey(conflictKey string) {
+func (txn *Txn) addConflictKey(conflictKey uint64) {
 	txn.Lock()
 	defer txn.Unlock()
 	if txn.conflicts == nil {
-		txn.conflicts = make(map[string]struct{})
+		txn.conflicts = make(map[uint64]struct{})
 	}
-	if len(conflictKey) > 0 {
+	if conflictKey > 0 {
 		txn.conflicts[conflictKey] = struct{}{}
 	}
 }
@@ -63,7 +62,7 @@ func (txn *Txn) FillContext(ctx *api.TxnContext, gid uint32) {
 		// We don'txn need to send the whole conflict key to Zero. Solving #2338
 		// should be done by sending a list of mutating predicates to Zero,
 		// along with the keys to be used for conflict detection.
-		fps := strconv.FormatUint(farm.Fingerprint64([]byte(key)), 36)
+		fps := strconv.FormatUint(key, 36)
 		if !x.HasString(ctx.Keys, fps) {
 			ctx.Keys = append(ctx.Keys, fps)
 		}
diff --git a/posting/oracle.go b/posting/oracle.go
index adc4045b075..59619124851 100644
--- a/posting/oracle.go
+++ b/posting/oracle.go
@@ -54,7 +54,7 @@ type Txn struct {
 
 	// Keeps track of conflict keys that should be used to determine if this
 	// transaction conflicts with another.
-	conflicts map[string]struct{}
+	conflicts map[uint64]struct{}
 
 	// Keeps track of last update wall clock. We use this fact later to
 	// determine unhealthy, stale txns.