wip

pkg/sql/catalog/catenumpb/encoded_datum.proto

@@ -20,4 +20,6 @@ enum DatumEncoding {
     DESCENDING_KEY = 1;
     // Indicates that the datum is encoded using the encoding used for values.
     VALUE = 2;
+    // Indicates that the datum is encoded using the legacy encoding for values.
+    VALUE_LEGACY = 3;
 }

pkg/sql/row/fetcher.go

@@ -25,7 +25,6 @@ import (
 	"github.com/cockroachdb/cockroach/pkg/sql/catalog/fetchpb"
 	"github.com/cockroachdb/cockroach/pkg/sql/rowenc"
 	"github.com/cockroachdb/cockroach/pkg/sql/rowenc/keyside"
-	"github.com/cockroachdb/cockroach/pkg/sql/rowenc/valueside"
 	"github.com/cockroachdb/cockroach/pkg/sql/rowinfra"
 	"github.com/cockroachdb/cockroach/pkg/sql/scrub"
 	"github.com/cockroachdb/cockroach/pkg/sql/sem/eval"
@@ -1076,21 +1075,17 @@ func (rf *Fetcher) processValueSingle(
 		return prettyKey, "", nil
 	}
 	typ := table.spec.FetchedColumns[idx].Type
-	// TODO(arjun): The value is a directly marshaled single value, so we
-	// unmarshal it eagerly here. This can potentially be optimized out,
-	// although that would require changing UnmarshalColumnValue to operate
-	// on bytes, and for Encode/DecodeTableValue to operate on marshaled
-	// single values.
-	value, err := valueside.UnmarshalLegacy(rf.args.Alloc, typ, kv.Value)
-	if err != nil {
-		return "", "", err
-	}
+	encValue := rowenc.EncDatumValueLegacyFromValue(kv.Value)
 	if rf.args.TraceKV {
-		prettyValue = value.String()
+		err := encValue.EnsureDecoded(typ, rf.args.Alloc)
+		if err != nil {
+			return "", "", err
+		}
+		prettyValue = encValue.Datum.String()
 	}
-	table.row[idx] = rowenc.DatumToEncDatum(typ, value)
+	table.row[idx] = encValue
 	if DebugRowFetch {
-		log.Infof(ctx, "Scan %s -> %v", kv.Key, value)
+		log.Infof(ctx, "Scan %d -> %v", kv.Key, encValue)
 	}
 	return prettyKey, prettyValue, nil
 }

pkg/sql/rowenc/encoded_datum.go

@@ -11,6 +11,7 @@ import (
 	"fmt"
 	"unsafe"
 
+	"github.com/cockroachdb/cockroach/pkg/roachpb"
 	"github.com/cockroachdb/cockroach/pkg/sql/catalog/catenumpb"
 	"github.com/cockroachdb/cockroach/pkg/sql/catalog/colinfo"
 	"github.com/cockroachdb/cockroach/pkg/sql/rowenc/keyside"
@@ -179,6 +180,18 @@ func EncDatumValueFromBufferWithOffsetsAndType(
 	return ed, buf[encLen:], nil
 }
 
+// EncDatumValueLegacyFromValue
+func EncDatumValueLegacyFromValue(value roachpb.Value) EncDatum {
+	if value.RawBytes == nil {
+		return NullEncDatum()
+	}
+	return EncDatum{
+		encoding: catenumpb.DatumEncoding_VALUE_LEGACY,
+		encoded:  value.TagAndDataBytes(),
+		Datum:    nil,
+	}
+}
+
 // DatumToEncDatum initializes an EncDatum with the given Datum.
 func DatumToEncDatum(ctyp *types.T, d tree.Datum) EncDatum {
 	ed, err := DatumToEncDatumEx(ctyp, d)
@@ -242,6 +255,9 @@ func (ed *EncDatum) IsNull() bool {
 		}
 		return typ == encoding.Null
 
+	case catenumpb.DatumEncoding_VALUE_LEGACY:
+		// should already have ed.Datum set to tree.DNull
+		return false
 	default:
 		panic(errors.AssertionFailedf("unknown encoding %s", ed.encoding))
 	}
@@ -264,6 +280,10 @@ func (ed *EncDatum) EnsureDecoded(typ *types.T, a *tree.DatumAlloc) error {
 		ed.Datum, rem, err = keyside.Decode(a, typ, ed.encoded, encoding.Descending)
 	case catenumpb.DatumEncoding_VALUE:
 		ed.Datum, rem, err = valueside.Decode(a, typ, ed.encoded)
+	case catenumpb.DatumEncoding_VALUE_LEGACY:
+		var v roachpb.Value
+		v.SetTagAndData(ed.encoded)
+		ed.Datum, err = valueside.UnmarshalLegacy(a, typ, v)
 	default:
 		return errors.AssertionFailedf("unknown encoding %d", redact.Safe(ed.encoding))
 	}