diff --git a/internal/db/base/collection_keys.go b/internal/db/base/collection_keys.go
index 31cdeef18c..015a2aeee3 100644
--- a/internal/db/base/collection_keys.go
+++ b/internal/db/base/collection_keys.go
@@ -11,10 +11,7 @@
 package base
 
 import (
-	"fmt"
-
 	"github.com/sourcenetwork/defradb/client"
-	"github.com/sourcenetwork/defradb/internal/core"
 	"github.com/sourcenetwork/defradb/internal/keys"
 )
 
@@ -35,29 +32,3 @@ func MakeDataStoreKeyWithCollectionAndDocID(
 		DocID:            docID,
 	}
 }
-
-func MakePrimaryIndexKeyForCRDT(
-	c client.CollectionDefinition,
-	ctype client.CType,
-	key keys.DataStoreKey,
-	fieldName string,
-) (keys.DataStoreKey, error) {
-	switch ctype {
-	case client.COMPOSITE:
-		return MakeDataStoreKeyWithCollectionDescription(c.Description).
-				WithInstanceInfo(key).
-				WithFieldID(core.COMPOSITE_NAMESPACE),
-			nil
-	case client.LWW_REGISTER, client.PN_COUNTER, client.P_COUNTER:
-		field, ok := c.GetFieldByName(fieldName)
-		if !ok {
-			return keys.DataStoreKey{}, client.NewErrFieldNotExist(fieldName)
-		}
-
-		return MakeDataStoreKeyWithCollectionDescription(c.Description).
-				WithInstanceInfo(key).
-				WithFieldID(fmt.Sprint(field.ID)),
-			nil
-	}
-	return keys.DataStoreKey{}, ErrInvalidCrdtType
-}
diff --git a/internal/db/fetcher/versioned.go b/internal/db/fetcher/versioned.go
index 508b0ea406..b2294f57e5 100644
--- a/internal/db/fetcher/versioned.go
+++ b/internal/db/fetcher/versioned.go
@@ -13,6 +13,7 @@ package fetcher
 import (
 	"container/list"
 	"context"
+	"fmt"
 
 	"github.com/ipfs/go-cid"
 	ds "github.com/ipfs/go-datastore"
@@ -27,7 +28,6 @@ import (
 	"github.com/sourcenetwork/defradb/datastore/memory"
 	"github.com/sourcenetwork/defradb/internal/core"
 	coreblock "github.com/sourcenetwork/defradb/internal/core/block"
-	"github.com/sourcenetwork/defradb/internal/db/base"
 	"github.com/sourcenetwork/defradb/internal/keys"
 	merklecrdt "github.com/sourcenetwork/defradb/internal/merkle/crdt"
 	"github.com/sourcenetwork/defradb/internal/planner/mapper"
@@ -99,7 +99,7 @@ type VersionedFetcher struct {
 
 	col client.Collection
 	// @todo index  *client.IndexDescription
-	mCRDTs map[uint32]merklecrdt.MerkleCRDT
+	mCRDTs map[client.FieldID]merklecrdt.MerkleCRDT
 }
 
 // Init initializes the VersionedFetcher.
@@ -118,7 +118,7 @@ func (vf *VersionedFetcher) Init(
 	vf.acp = acp
 	vf.col = col
 	vf.queuedCids = list.New()
-	vf.mCRDTs = make(map[uint32]merklecrdt.MerkleCRDT)
+	vf.mCRDTs = make(map[client.FieldID]merklecrdt.MerkleCRDT)
 	vf.txn = txn
 
 	// create store
@@ -182,7 +182,7 @@ func (vf *VersionedFetcher) Start(ctx context.Context, spans core.Spans) error {
 	}
 
 	vf.ctx = ctx
-	vf.dsKey = dk
+	vf.dsKey = dk.WithCollectionRoot(vf.col.Description().RootID)
 	vf.version = c
 
 	if err := vf.seekTo(vf.version); err != nil {
@@ -352,7 +352,17 @@ func (vf *VersionedFetcher) merge(c cid.Cid) error {
 	}
 
 	// first arg 0 is the index for the composite DAG in the mCRDTs cache
-	if err := vf.processBlock(0, block, link, client.COMPOSITE, client.FieldKind_None, ""); err != nil {
+	mcrdt, exists := vf.mCRDTs[0]
+	if !exists {
+		mcrdt = merklecrdt.NewMerkleCompositeDAG(
+			vf.store,
+			keys.CollectionSchemaVersionKey{},
+			vf.dsKey.WithFieldID(core.COMPOSITE_NAMESPACE),
+		)
+		vf.mCRDTs[0] = mcrdt
+	}
+	err = mcrdt.Clock().ProcessBlock(vf.ctx, block, link)
+	if err != nil {
 		return err
 	}
 
@@ -368,7 +378,7 @@ func (vf *VersionedFetcher) merge(c cid.Cid) error {
 		if !ok {
 			return client.NewErrFieldNotExist(l.Name)
 		}
-		if err := vf.processBlock(uint32(field.ID), subBlock, l.Link, field.Typ, field.Kind, l.Name); err != nil {
+		if err := vf.processBlock(subBlock, l.Link, field, l.Name); err != nil {
 			return err
 		}
 	}
@@ -377,32 +387,25 @@ func (vf *VersionedFetcher) merge(c cid.Cid) error {
 }
 
 func (vf *VersionedFetcher) processBlock(
-	crdtIndex uint32,
 	block *coreblock.Block,
 	blockLink cidlink.Link,
-	ctype client.CType,
-	kind client.FieldKind,
+	field client.FieldDefinition,
 	fieldName string,
 ) (err error) {
-	// handle CompositeDAG
-	mcrdt, exists := vf.mCRDTs[crdtIndex]
+	mcrdt, exists := vf.mCRDTs[field.ID]
 	if !exists {
-		dsKey, err := base.MakePrimaryIndexKeyForCRDT(vf.col.Definition(), ctype, vf.dsKey, fieldName)
-		if err != nil {
-			return err
-		}
 		mcrdt, err = merklecrdt.InstanceWithStore(
 			vf.store,
 			keys.CollectionSchemaVersionKey{},
-			ctype,
-			kind,
-			dsKey,
+			field.Typ,
+			field.Kind,
+			vf.dsKey.WithFieldID(fmt.Sprint(field.ID)),
 			fieldName,
 		)
 		if err != nil {
 			return err
 		}
-		vf.mCRDTs[crdtIndex] = mcrdt
+		vf.mCRDTs[field.ID] = mcrdt
 	}
 
 	return mcrdt.Clock().ProcessBlock(vf.ctx, block, blockLink)
diff --git a/internal/keys/datastore_doc.go b/internal/keys/datastore_doc.go
index 1665fb7ea3..cd8ac60917 100644
--- a/internal/keys/datastore_doc.go
+++ b/internal/keys/datastore_doc.go
@@ -86,6 +86,12 @@ func (k DataStoreKey) WithDeletedFlag() DataStoreKey {
 	return newKey
 }
 
+func (k DataStoreKey) WithCollectionRoot(colRoot uint32) DataStoreKey {
+	newKey := k
+	newKey.CollectionRootID = colRoot
+	return newKey
+}
+
 func (k DataStoreKey) WithDocID(docID string) DataStoreKey {
 	newKey := k
 	newKey.DocID = docID
diff --git a/internal/merkle/crdt/merklecrdt.go b/internal/merkle/crdt/merklecrdt.go
index 3dd47ad0dc..9b4cd019a8 100644
--- a/internal/merkle/crdt/merklecrdt.go
+++ b/internal/merkle/crdt/merklecrdt.go
@@ -66,12 +66,6 @@ func InstanceWithStore(
 			cType == client.PN_COUNTER,
 			kind.(client.ScalarKind),
 		), nil
-	case client.COMPOSITE:
-		return NewMerkleCompositeDAG(
-			store,
-			schemaVersionKey,
-			key,
-		), nil
 	}
 	return nil, client.NewErrUnknownCRDT(cType)
 }