diff --git a/bats/compatibility/corona-virus-test.sh b/bats/compatibility/corona-virus-test.sh
index 68b7c60ec84..b42aa07d34b 100755
--- a/bats/compatibility/corona-virus-test.sh
+++ b/bats/compatibility/corona-virus-test.sh
@@ -60,7 +60,7 @@ function export_tables() {
     places
   do
     dolt table export "$table" "$table$1.csv"
-    dolt sql -r csv -q "select * from $table" > "$table$1.sql.csv"
+    dolt sql -r csv -q "select * from $table" | sed 's/<NULL>//g' > "$table$1.sql.csv"
   done
 }
 
@@ -99,7 +99,7 @@ local_bin="`pwd`"/"$bin"
 PATH="$local_bin":"$PATH" dolt clone Liquidata/corona-virus
 pushd "corona-virus"
 PATH="$local_bin":"$PATH" export_tables "-pre"
-dolt migrate
+time dolt migrate
 export_tables "-post"
 diff_tables
 echo "success!"
diff --git a/go/libraries/doltcore/rebase/rebase_tag.go b/go/libraries/doltcore/rebase/rebase_tag.go
index 7292a8b1284..e2830e12d7e 100644
--- a/go/libraries/doltcore/rebase/rebase_tag.go
+++ b/go/libraries/doltcore/rebase/rebase_tag.go
@@ -27,6 +27,7 @@ import (
 	"github.com/liquidata-inc/dolt/go/libraries/doltcore/schema"
 	"github.com/liquidata-inc/dolt/go/libraries/doltcore/schema/encoding"
 	"github.com/liquidata-inc/dolt/go/libraries/doltcore/table/typed"
+	"github.com/liquidata-inc/dolt/go/libraries/doltcore/table/typed/noms"
 	"github.com/liquidata-inc/dolt/go/libraries/utils/set"
 	ndiff "github.com/liquidata-inc/dolt/go/store/diff"
 	"github.com/liquidata-inc/dolt/go/store/hash"
@@ -404,7 +405,7 @@ func replayCommitWithNewTag(ctx context.Context, root, parentRoot, rebasedParent
 			return nil, err
 		}
 
-		rebasedRows, err := replayRowDiffs(ctx, rebasedSch, rows, parentRows, rebasedParentRows, tableMapping)
+		rebasedRows, err := replayRowDiffs(ctx, rebasedParentRoot.VRW(), rebasedSch, rows, parentRows, rebasedParentRows, tableMapping)
 
 		if err != nil {
 			return nil, err
@@ -442,7 +443,7 @@ func replayCommitWithNewTag(ctx context.Context, root, parentRoot, rebasedParent
 	return newRoot, nil
 }
 
-func replayRowDiffs(ctx context.Context, rSch schema.Schema, rows, parentRows, rebasedParentRows types.Map, tagMapping map[uint64]uint64) (types.Map, error) {
+func replayRowDiffs(ctx context.Context, vrw types.ValueReadWriter, rSch schema.Schema, rows, parentRows, rebasedParentRows types.Map, tagMapping map[uint64]uint64) (types.Map, error) {
 
 	unmappedTags := set.NewUint64Set(rSch.GetAllCols().Tags)
 	tm := make(map[uint64]uint64)
@@ -454,8 +455,7 @@ func replayRowDiffs(ctx context.Context, rSch schema.Schema, rows, parentRows, r
 		tm[t] = t
 	}
 
-	// we will apply modified differences to the rebasedParent
-	rebasedRowEditor := rebasedParentRows.Edit()
+	nmu := noms.NewNomsMapUpdater(ctx, vrw, rebasedParentRows, rSch, func(stats types.AppliedEditStats) {})
 
 	ad := diff.NewAsyncDiffer(diffBufSize)
 	// get all differences (including merges) between original commit and its parent
@@ -486,16 +486,25 @@ func replayRowDiffs(ctx context.Context, rSch schema.Schema, rows, parentRows, r
 
 			switch d.ChangeType {
 			case types.DiffChangeAdded:
-				rebasedRowEditor.Set(key, newVal)
+				err = nmu.WriteEdit(ctx, key, newVal)
 			case types.DiffChangeRemoved:
-				rebasedRowEditor.Remove(key)
+				err = nmu.WriteEdit(ctx, key, nil)
 			case types.DiffChangeModified:
-				rebasedRowEditor.Set(key, newVal)
+				err = nmu.WriteEdit(ctx, key, newVal)
+			}
+
+			if err != nil {
+				return types.EmptyMap, err
 			}
 		}
 	}
 
-	return rebasedRowEditor.Map(ctx)
+	err := nmu.Close(ctx)
+	if err != nil {
+		return types.EmptyMap, err
+	}
+
+	return *nmu.GetMap(), nil
 }
 
 func dropValsForDeletedColumns(ctx context.Context, nbf *types.NomsBinFormat, rows types.Map, sch, parentSch schema.Schema) (types.Map, error) {
diff --git a/go/libraries/doltcore/table/typed/noms/noms_map_updater.go b/go/libraries/doltcore/table/typed/noms/noms_map_updater.go
index ab5cd9a9339..678ca0ca286 100644
--- a/go/libraries/doltcore/table/typed/noms/noms_map_updater.go
+++ b/go/libraries/doltcore/table/typed/noms/noms_map_updater.go
@@ -96,6 +96,11 @@ func (nmu *NomsMapUpdater) GetSchema() schema.Schema {
 
 // WriteRow will write a row to a table
 func (nmu *NomsMapUpdater) WriteRow(ctx context.Context, r row.Row) error {
+	return nmu.WriteEdit(ctx, r.NomsMapKey(nmu.sch), r.NomsMapValue(nmu.sch))
+}
+
+// WriteEdit will write an edit to a table's edit accumulator
+func (nmu *NomsMapUpdater) WriteEdit(ctx context.Context, pk types.LesserValuable, fieldVals types.Valuable) error {
 	if nmu.acc == nil {
 		return errors.New("Attempting to write after closing.")
 	}
@@ -105,9 +110,6 @@ func (nmu *NomsMapUpdater) WriteRow(ctx context.Context, r row.Row) error {
 	}
 
 	err := func() error {
-		pk := r.NomsMapKey(nmu.sch)
-		fieldVals := r.NomsMapValue(nmu.sch)
-
 		nmu.acc.AddEdit(pk, fieldVals)
 		nmu.count++