exec: fix explain(vec) for queries with subqueries

pkg/sql/distsqlrun/column_exec_setup.go

@@ -774,12 +774,13 @@ func planProjectionOperators(
 	case *tree.BinaryExpr:
 		return planProjectionExpr(ctx, t.Operator, t.ResolvedType(), t.TypedLeft(), t.TypedRight(), columnTypes, input)
 	case *tree.CastExpr:
-		op, resultIdx, ct, memUsed, err = planProjectionOperators(ctx, t.Expr.(tree.TypedExpr), columnTypes, input)
+		expr := t.Expr.(tree.TypedExpr)
+		op, resultIdx, ct, memUsed, err = planProjectionOperators(ctx, expr, columnTypes, input)
 		if err != nil {
 			return nil, 0, nil, 0, err
 		}
 		outputIdx := len(ct)
-		op, err = exec.GetCastOperator(op, resultIdx, outputIdx, t.Expr.(tree.TypedExpr).ResolvedType(), t.Type)
+		op, err = exec.GetCastOperator(op, resultIdx, outputIdx, expr.ResolvedType(), t.Type)
 		ct = append(ct, *t.Type)
 		if sMem, ok := op.(exec.StaticMemoryOperator); ok {
 			memUsed += sMem.EstimateStaticMemoryUsage()

pkg/sql/exec/cast_tmpl.go

@@ -21,6 +21,7 @@ package exec
 
 import (
 	"context"
+	"fmt"
 	"math"
 
 	"github.com/cockroachdb/apd"
@@ -73,6 +74,14 @@ var _ interface{} = execgen.GET
 func GetCastOperator(
 	input Operator, colIdx int, resultIdx int, fromType *semtypes.T, toType *semtypes.T,
 ) (Operator, error) {
+	if fromType.Family() == semtypes.UnknownFamily {
+		return &castOpNullAny{
+			OneInputNode: NewOneInputNode(input),
+			colIdx:       colIdx,
+			outputIdx:    resultIdx,
+			toType:       typeconv.FromColumnType(toType),
+		}, nil
+	}
 	switch from := typeconv.FromColumnType(fromType); from {
 	// {{ range $typ, $overloads := . }}
 	case coltypes._ALLTYPES:
@@ -98,6 +107,57 @@ func GetCastOperator(
 	}
 }
 
+type castOpNullAny struct {
+	OneInputNode
+	colIdx    int
+	outputIdx int
+	toType    coltypes.T
+}
+
+var _ StaticMemoryOperator = &castOpNullAny{}
+
+func (c *castOpNullAny) EstimateStaticMemoryUsage() int {
+	return EstimateBatchSizeBytes([]coltypes.T{c.toType}, coldata.BatchSize)
+}
+
+func (c *castOpNullAny) Init() {
+	c.input.Init()
+}
+
+func (c *castOpNullAny) Next(ctx context.Context) coldata.Batch {
+	batch := c.input.Next(ctx)
+	n := batch.Length()
+	if n == 0 {
+		return batch
+	}
+	if c.outputIdx == batch.Width() {
+		batch.AppendCol(c.toType)
+	}
+	vec := batch.ColVec(c.colIdx)
+	projVec := batch.ColVec(c.outputIdx)
+	vecNulls := vec.Nulls()
+	projNulls := projVec.Nulls()
+	if sel := batch.Selection(); sel != nil {
+		sel = sel[:n]
+		for _, i := range sel {
+			if vecNulls.NullAt(i) {
+				projNulls.SetNull(i)
+			} else {
+				execerror.VectorizedInternalPanic(errors.Errorf("unexpected non-null at index %d", i))
+			}
+		}
+	} else {
+		for i := uint16(0); i < n; i++ {
+			if vecNulls.NullAt(uint16(i)) {
+				projNulls.SetNull(uint16(i))
+			} else {
+				execerror.VectorizedInternalPanic(fmt.Errorf("unexpected non-null at index %d", i))
+			}
+		}
+	}
+	return batch
+}
+
 // {{ range $typ, $overloads := . }}
 // {{ range $overloads }}
 // {{ if isCastFuncSet . }}

pkg/sql/explain_vec.go

@@ -20,6 +20,8 @@ import (
 	"github.com/cockroachdb/cockroach/pkg/sql/distsqlrun"
 	"github.com/cockroachdb/cockroach/pkg/sql/exec"
 	"github.com/cockroachdb/cockroach/pkg/sql/sem/tree"
+	"github.com/cockroachdb/cockroach/pkg/sql/sessiondata"
+	"github.com/cockroachdb/cockroach/pkg/util/mon"
 	"github.com/cockroachdb/cockroach/pkg/util/treeprinter"
 )
 
@@ -37,6 +39,7 @@ type explainVecNode struct {
 		// The current row returned by the node.
 		values tree.Datums
 	}
+	subqueryPlans []subquery
 }
 
 type flowWithNode struct {
@@ -62,7 +65,17 @@ func (n *explainVecNode) startExec(params runParams) error {
 	planCtx.ignoreClose = true
 	planCtx.planner = params.p
 	planCtx.stmtType = n.stmtType
-	planCtx.noEvalSubqueries = true
+	outerSubqueries := planCtx.planner.curPlan.subqueryPlans
+	defer func() {
+		planCtx.planner.curPlan.subqueryPlans = outerSubqueries
+	}()
+	planCtx.planner.curPlan.subqueryPlans = n.subqueryPlans
+	for i := range planCtx.planner.curPlan.subqueryPlans {
+		p := &planCtx.planner.curPlan.subqueryPlans[i]
+		// Fake subquery results - they're not important for our explain output.
+		p.started = true
+		p.result = tree.DNull
+	}
 
 	var plan PhysicalPlan
 	var err error
@@ -88,8 +101,16 @@ func (n *explainVecNode) startExec(params runParams) error {
 	flowCtx := &distsqlrun.FlowCtx{
 		NodeID:  planCtx.EvalContext().NodeID,
 		EvalCtx: planCtx.EvalContext(),
-		Cfg:     &distsqlrun.ServerConfig{},
+		Cfg: &distsqlrun.ServerConfig{
+			Settings:    params.p.execCfg.Settings,
+			DiskMonitor: &mon.BytesMonitor{},
+		},
 	}
+	// Temporarily set vectorize to on so that we can get the whole plan back even
+	// if we wouldn't support it due to lack of streaming.
+	origMode := flowCtx.EvalCtx.SessionData.VectorizeMode
+	flowCtx.EvalCtx.SessionData.VectorizeMode = sessiondata.VectorizeExperimentalOn
+	defer func() { flowCtx.EvalCtx.SessionData.VectorizeMode = origMode }()
 
 	sortedFlows := make([]flowWithNode, 0, len(flows))
 	for nodeID, flow := range flows {