distsql: support tuples

Closes cockroachdb#15938.

Release note (performance improvement): using tuples in a query no
longer reverts you to single node local SQL execution.

pkg/sql/distsql_physical_planner.go

@@ -33,7 +33,6 @@ import (
 	"github.com/cockroachdb/cockroach/pkg/sql/distsqlplan"
 	"github.com/cockroachdb/cockroach/pkg/sql/distsqlrun"
 	"github.com/cockroachdb/cockroach/pkg/sql/sem/tree"
-	"github.com/cockroachdb/cockroach/pkg/sql/sem/types"
 	"github.com/cockroachdb/cockroach/pkg/sql/sqlbase"
 	"github.com/cockroachdb/cockroach/pkg/storage"
 	"github.com/cockroachdb/cockroach/pkg/util"
@@ -280,15 +279,6 @@ func newQueryNotSupportedErrorf(format string, args ...interface{}) error {
 var mutationsNotSupportedError = newQueryNotSupportedError("mutations not supported")
 var setNotSupportedError = newQueryNotSupportedError("SET / SET CLUSTER SETTING should never distribute")
 
-// leafType returns the element type if the given type is an array, and the type
-// itself otherwise.
-func leafType(t types.T) types.T {
-	if a, ok := t.(types.TArray); ok {
-		return leafType(a.Typ)
-	}
-	return t
-}
-
 // checkSupportForNode returns a distRecommendation (as described above) or an
 // error if the plan subtree is not supported by DistSQL.
 // TODO(radu): add tests for this.
@@ -301,11 +291,7 @@ func (dsp *DistSQLPlanner) checkSupportForNode(node planNode) (distRecommendatio
 		return dsp.checkSupportForNode(n.source.plan)
 
 	case *renderNode:
-		for i, e := range n.render {
-			typ := n.columns[i].Typ
-			if leafType(typ).FamilyEqual(types.FamTuple) {
-				return 0, newQueryNotSupportedErrorf("unsupported render type %s", typ)
-			}
+		for _, e := range n.render {
 			if err := dsp.checkExpr(e); err != nil {
 				return 0, err
 			}

pkg/sql/distsqlrun/hash_row_container.go

@@ -417,7 +417,7 @@ func (h *hashDiskRowContainer) Init(
 	h.columnEncoder.init(types, storedEqCols)
 	// Provide the diskRowContainer with an ordering on the equality columns of
 	// the rows that we will store. This will result in rows with the
-	// same equality columns ocurring contiguously in the keyspace.
+	// same equality columns occurring contiguously in the keyspace.
 	ordering := make(sqlbase.ColumnOrdering, len(storedEqCols))
 	for i := range ordering {
 		ordering[i] = sqlbase.ColumnOrderInfo{

pkg/sql/distsqlrun/processors.go

@@ -67,7 +67,7 @@ type ProcOutputHelper struct {
 	//
 	// If renderExprs is set, these types correspond to the types of those
 	// expressions.
-	// If outpuCols is set, these types correspond to the types of
+	// If outputCols is set, these types correspond to the types of
 	// those columns.
 	// If neither is set, this is the internal schema of the processor.
 	outputTypes []sqlbase.ColumnType

pkg/sql/distsqlrun/version_history.txt

@@ -62,3 +62,6 @@
     - Enhancements to lookup joins. They now support joining against secondary
       indexes as well as left outer joins. Left join support required two
       additional fields on JoinReaderSpec: index_filter_expr and type.
+- Version: 15 (MinAcceptedVersion: 6)
+    - Add support for processing queries with tuples in DistSQL. Old versions
+      would not recognize the new tuple field in the proto.

pkg/sql/logictest/testdata/logic_test/select

@@ -249,7 +249,7 @@ SELECT * FROM xyzw ORDER BY x OFFSET 1 + 0.0
 ----
 4 5 6 7
 
-query T
+query T rowsort
 SELECT (x,y) FROM xyzw
 ----
 (1,2)

pkg/sql/sem/tree/datum.go

@@ -2609,6 +2609,10 @@ func (*DTuple) AmbiguousFormat() bool { return false }
 // Format implements the NodeFormatter interface.
 // TODO(bram): We don't format tuples in the same way as postgres. See #25522.
 func (d *DTuple) Format(ctx *FmtCtx) {
+	if ctx.HasFlags(FmtParsable) && (len(d.D) == 0) {
+		ctx.WriteString("ROW()")
+		return
+	}
 	ctx.FormatNode(&d.D)
 }
 

pkg/sql/sem/tree/format_test.go

@@ -194,6 +194,8 @@ func TestFormatExpr(t *testing.T) {
 			`unique_rowid() + 123:::INT`},
 		{`sqrt(123.0) + 456`, tree.FmtParsable,
 			`sqrt(123.0:::DECIMAL) + 456:::DECIMAL`},
+		{`ROW()`, tree.FmtParsable, `ROW()`},
+		{`ROW()`, tree.FmtSimple, `()`},
 		{`now() + interval '3s'`, tree.FmtSimple,
 			`now() + '3s'`},
 		{`now() + interval '3s'`, tree.FmtParsable,

pkg/sql/sqlbase/encoded_datum.go

@@ -203,7 +203,7 @@ func (ed *EncDatum) EnsureDecoded(typ *ColumnType, a *DatumAlloc) error {
 		panic(fmt.Sprintf("unknown encoding %s", ed.encoding))
 	}
 	if err != nil {
-		return err
+		return errors.Wrapf(err, "error decoding %d bytes", len(ed.encoded))
 	}
 	if len(rem) != 0 {
 		ed.Datum = nil

pkg/sql/sqlbase/structured.go

@@ -652,7 +652,7 @@ func DatumTypeHasCompositeKeyEncoding(typ types.T) bool {
 // MustBeValueEncoded returns true if columns of the given kind can only be value
 // encoded.
 func MustBeValueEncoded(semanticType ColumnType_SemanticType) bool {
-	return semanticType == ColumnType_ARRAY || semanticType == ColumnType_JSON
+	return semanticType == ColumnType_ARRAY || semanticType == ColumnType_JSON || semanticType == ColumnType_TUPLE
 }
 
 // HasOldStoredColumns returns whether the index has stored columns in the old
@@ -2305,6 +2305,9 @@ func DatumTypeToColumnSemanticType(ptyp types.T) (ColumnType_SemanticType, error
 		if ptyp.FamilyEqual(types.FamCollatedString) {
 			return ColumnType_COLLATEDSTRING, nil
 		}
+		if ptyp.FamilyEqual(types.FamTuple) {
+			return ColumnType_TUPLE, nil
+		}
 		if wrapper, ok := ptyp.(types.TOidWrapper); ok {
 			return DatumTypeToColumnSemanticType(wrapper.T)
 		}
@@ -2330,6 +2333,17 @@ func DatumTypeToColumnType(ptyp types.T) (ColumnType, error) {
 			cs := t.Typ.(types.TCollatedString)
 			ctyp.Locale = &cs.Locale
 		}
+	case types.TTuple:
+		ctyp.SemanticType = ColumnType_TUPLE
+		ctyp.TupleContents = make([]ColumnType, len(t.Types))
+		for i, tc := range t.Types {
+			var err error
+			ctyp.TupleContents[i], err = DatumTypeToColumnType(tc)
+			if err != nil {
+				return ColumnType{}, err
+			}
+		}
+		return ctyp, nil
 	default:
 		semanticType, err := DatumTypeToColumnSemanticType(ptyp)
 		if err != nil {
@@ -2372,6 +2386,8 @@ func columnSemanticTypeToDatumType(c *ColumnType, k ColumnType_SemanticType) typ
 		return types.INet
 	case ColumnType_JSON:
 		return types.JSON
+	case ColumnType_TUPLE:
+		return types.FamTuple
 	case ColumnType_COLLATEDSTRING:
 		if c.Locale == nil {
 			panic("locale is required for COLLATEDSTRING")
@@ -2397,6 +2413,14 @@ func (c *ColumnType) ToDatumType() types.T {
 	switch c.SemanticType {
 	case ColumnType_ARRAY:
 		return types.TArray{Typ: columnSemanticTypeToDatumType(c, *c.ArrayContents)}
+	case ColumnType_TUPLE:
+		datums := types.TTuple{
+			Types: make([]types.T, len(c.TupleContents)),
+		}
+		for i := range c.TupleContents {
+			datums.Types[i] = c.TupleContents[i].ToDatumType()
+		}
+		return datums
 	default:
 		return columnSemanticTypeToDatumType(c, c.SemanticType)
 	}