opt: add support for ALTER TABLE/INDEX SPLIT AT

Adding optimizer support for `tree.Split`. This statement has a
relational input, so it can't be implemented as an "opaque".

Note that as part of this change, we move all the "fixed" planNode
column definitions to `sqlbase` and we add an `Ordinal()` method to
`cat.Index`.

Release note: None

pkg/sql/data_source.go

@@ -435,7 +435,7 @@ func (p *planner) getSequenceSource(
 	}
 	return planDataSource{
 		plan: node,
-		info: sqlbase.NewSourceInfoForSingleTable(tn, sequenceSelectColumns),
+		info: sqlbase.NewSourceInfoForSingleTable(tn, sqlbase.SequenceSelectColumns),
 	}, nil
 }
 

pkg/sql/opt/bench/stub_factory.go

@@ -289,3 +289,9 @@ func (f *stubFactory) ConstructErrorIfRows(
 func (f *stubFactory) ConstructOpaque(metadata opt.OpaqueMetadata) (exec.Node, error) {
 	return struct{}{}, nil
 }
+
+func (f *stubFactory) ConstructAlterTableSplit(
+	index cat.Index, input exec.Node, expiration tree.TypedExpr,
+) (exec.Node, error) {
+	return struct{}{}, nil
+}

pkg/sql/opt/cat/index.go

@@ -38,6 +38,10 @@ type Index interface {
 	// Table returns a reference to the table this index is based on.
 	Table() Table
 
+	// Ordinal returns the ordinal of this index within the context of its Table.
+	// Specifically idx = Table().Index(idx.Ordinal).
+	Ordinal() int
+
 	// IsUnique returns true if this index is declared as UNIQUE in the schema.
 	IsUnique() bool
 

pkg/sql/opt/exec/execbuilder/relational.go

@@ -244,6 +244,9 @@ func (b *Builder) buildRelational(e memo.RelExpr) (execPlan, error) {
 	case *memo.OpaqueRelExpr:
 		ep, err = b.buildOpaque(t)
 
+	case *memo.AlterTableSplitExpr:
+		ep, err = b.buildAlterTableSplit(t)
+
 	default:
 		if opt.IsSetOp(e) {
 			ep, err = b.buildSetOp(e)

pkg/sql/opt/exec/execbuilder/statement.go

@@ -95,8 +95,8 @@ func (b *Builder) buildExplain(explain *memo.ExplainExpr) (execPlan, error) {
 	}
 
 	ep := execPlan{root: node}
-	for i := range explain.ColList {
-		ep.outputCols.Set(int(explain.ColList[i]), i)
+	for i, c := range explain.ColList {
+		ep.outputCols.Set(int(c), i)
 	}
 	// The subqueries are now owned by the explain node; remove them so they don't
 	// also show up in the final plan.
@@ -110,10 +110,34 @@ func (b *Builder) buildShowTrace(show *memo.ShowTraceForSessionExpr) (execPlan,
 		return execPlan{}, err
 	}
 	ep := execPlan{root: node}
-	for i := range show.ColList {
-		ep.outputCols.Set(int(show.ColList[i]), i)
+	for i, c := range show.ColList {
+		ep.outputCols.Set(int(c), i)
+	}
+	return ep, nil
+}
+
+func (b *Builder) buildAlterTableSplit(split *memo.AlterTableSplitExpr) (execPlan, error) {
+	input, err := b.buildRelational(split.Input)
+	if err != nil {
+		return execPlan{}, err
+	}
+	scalarCtx := buildScalarCtx{}
+	expiration, err := b.buildScalar(&scalarCtx, split.Expiration)
+	if err != nil {
+		return execPlan{}, err
+	}
+	table := b.mem.Metadata().Table(split.Table)
+	node, err := b.factory.ConstructAlterTableSplit(
+		table.Index(split.Index),
+		input.root,
+		expiration,
+	)
+	if err != nil {
+		return execPlan{}, err
+	}
+	ep := execPlan{root: node}
+	for i, c := range split.Columns {
+		ep.outputCols.Set(int(c), i)
 	}
-	// The subqueries are now owned by the explain node; remove them so they don't
-	// also show up in the final plan.
 	return ep, nil
 }

pkg/sql/opt/exec/execbuilder/testdata/ddl

@@ -91,17 +91,12 @@ CREATE TABLE s (k1 INT, k2 INT, v INT, PRIMARY KEY (k1,k2))
 query TTTTT colnames
 EXPLAIN (VERBOSE) ALTER TABLE s SPLIT AT SELECT k1,k2 FROM s ORDER BY k1 LIMIT 3
 ----
-tree                 field     description       columns                              ordering
-split                ·         ·                 (key, pretty, split_enforced_until)  ·
- └── limit           ·         ·                 (k1, k2)                             k1!=NULL; k2!=NULL; key(k1,k2); +k1
-      │              count     3                 ·                                    ·
-      └── render     ·         ·                 (k1, k2)                             k1!=NULL; k2!=NULL; key(k1,k2); +k1
-           │         render 0  test.public.s.k1  ·                                    ·
-           │         render 1  test.public.s.k2  ·                                    ·
-           └── scan  ·         ·                 (k1, k2, v[omitted])                 k1!=NULL; k2!=NULL; key(k1,k2); +k1
-·                    table     s@primary         ·                                    ·
-·                    spans     ALL               ·                                    ·
-·                    limit     3                 ·                                    ·
+tree       field  description  columns                              ordering
+split      ·      ·            (key, pretty, split_enforced_until)  ·
+ └── scan  ·      ·            (k1, k2)                             +k1
+·          table  s@primary    ·                                    ·
+·          spans  ALL          ·                                    ·
+·          limit  3            ·                                    ·
 
 statement ok
 DROP TABLE t; DROP TABLE other

pkg/sql/opt/exec/execbuilder/testdata/subquery

@@ -9,19 +9,16 @@ CREATE TABLE abc (a INT PRIMARY KEY, b INT, c INT)
 query TTT
 EXPLAIN ALTER TABLE abc SPLIT AT VALUES ((SELECT 42))
 ----
-root                               ·             ·
- ├── split                         ·             ·
- │    └── values                   ·             ·
- │                                 size          1 column, 1 row
- └── subquery                      ·             ·
-      │                            id            @S1
-      │                            original sql  (SELECT 42)
-      │                            exec mode     one row
-      └── max1row                  ·             ·
-           └── limit               ·             ·
-                │                  count         2
-                └── render         ·             ·
-                     └── emptyrow  ·             ·
+root              ·             ·
+ ├── split        ·             ·
+ │    └── values  ·             ·
+ │                size          1 column, 1 row
+ └── subquery     ·             ·
+      │           id            @S1
+      │           original sql  (SELECT 42)
+      │           exec mode     one row
+      └── values  ·             ·
+·                 size          1 column, 1 row
 
 statement ok
 ALTER TABLE abc SPLIT AT VALUES ((SELECT 1))

pkg/sql/opt/exec/factory.go

@@ -404,6 +404,10 @@ type Factory interface {
 
 	// ConstructOpaque creates a node for an opaque operator.
 	ConstructOpaque(metadata opt.OpaqueMetadata) (Node, error)
+
+	// ConstructAlterTableSplit creates a node that implements ALTER TABLE/INDEX
+	// SPLIT AT.
+	ConstructAlterTableSplit(index cat.Index, input Node, expiration tree.TypedExpr) (Node, error)
 }
 
 // OutputOrdering indicates the required output ordering on a Node that is being

pkg/sql/opt/memo/expr_format.go

@@ -967,6 +967,14 @@ func FormatPrivate(f *ExprFmtCtx, private interface{}, physProps *physical.Requi
 		f.Buffer.WriteByte(' ')
 		f.Buffer.WriteString(t.Metadata.String())
 
+	case *AlterTableSplitPrivate:
+		tab := f.Memo.metadata.Table(t.Table)
+		if t.Index == cat.PrimaryIndex {
+			fmt.Fprintf(f.Buffer, " %s", tableAlias(f, t.Table))
+		} else {
+			fmt.Fprintf(f.Buffer, " %s@%s", tableAlias(f, t.Table), tab.Index(t.Index).Name())
+		}
+
 	case *JoinPrivate:
 		// Nothing to show; flags are shown separately.
 

pkg/sql/opt/memo/logical_props_builder.go

@@ -684,25 +684,24 @@ func (b *logicalPropsBuilder) buildValuesProps(values *ValuesExpr, rel *props.Re
 	}
 }
 
-func (b *logicalPropsBuilder) buildExplainProps(explain *ExplainExpr, rel *props.Relational) {
-	BuildSharedProps(b.mem, explain, &rel.Shared)
+func (b *logicalPropsBuilder) buildBasicProps(e opt.Expr, cols opt.ColList, rel *props.Relational) {
+	BuildSharedProps(b.mem, e, &rel.Shared)
 
 	// Output Columns
 	// --------------
-	// Output columns are stored in the definition.
-	rel.OutputCols = explain.ColList.ToSet()
+	rel.OutputCols = cols.ToSet()
 
 	// Not Null Columns
 	// ----------------
 	// All columns are assumed to be nullable.
 
 	// Outer Columns
 	// -------------
-	// EXPLAIN doesn't allow outer columns.
+	// No outer columns.
 
 	// Functional Dependencies
 	// -----------------------
-	// Explain operator has an empty FD set.
+	// Empty FD set.
 
 	// Cardinality
 	// -----------
@@ -716,39 +715,28 @@ func (b *logicalPropsBuilder) buildExplainProps(explain *ExplainExpr, rel *props
 	}
 }
 
+func (b *logicalPropsBuilder) buildExplainProps(explain *ExplainExpr, rel *props.Relational) {
+	b.buildBasicProps(explain, explain.ColList, rel)
+}
+
 func (b *logicalPropsBuilder) buildShowTraceForSessionProps(
 	showTrace *ShowTraceForSessionExpr, rel *props.Relational,
 ) {
-	BuildSharedProps(b.mem, showTrace, &rel.Shared)
-
-	// Output Columns
-	// --------------
-	// Output columns are stored in the definition.
-	rel.OutputCols = showTrace.ColList.ToSet()
-
-	// Not Null Columns
-	// ----------------
-	// All columns are assumed to be nullable.
-
-	// Outer Columns
-	// -------------
-	// SHOW TRACE doesn't allow outer columns.
-
-	// Functional Dependencies
-	// -----------------------
-	// ShowTrace operator has an empty FD set.
-
-	// Cardinality
-	// -----------
-	// Don't make any assumptions about cardinality of output.
-	rel.Cardinality = props.AnyCardinality
+	b.buildBasicProps(showTrace, showTrace.ColList, rel)
+}
 
-	// Statistics
-	// ----------
-	if !b.disableStats {
-		b.sb.buildUnknown(rel)
-	}
+func (b *logicalPropsBuilder) buildOpaqueRelProps(op *OpaqueRelExpr, rel *props.Relational) {
+	b.buildBasicProps(op, op.Columns, rel)
+	rel.CanHaveSideEffects = true
+	rel.CanMutate = true
+}
 
+func (b *logicalPropsBuilder) buildAlterTableSplitProps(
+	split *AlterTableSplitExpr, rel *props.Relational,
+) {
+	b.buildBasicProps(split, split.Columns, rel)
+	rel.CanHaveSideEffects = true
+	rel.CanMutate = true
 }
 
 func (b *logicalPropsBuilder) buildLimitProps(limit *LimitExpr, rel *props.Relational) {
@@ -1785,39 +1773,6 @@ func (h *joinPropsHelper) cardinality() props.Cardinality {
 	}
 }
 
-func (b *logicalPropsBuilder) buildOpaqueRelProps(op *OpaqueRelExpr, rel *props.Relational) {
-	BuildSharedProps(b.mem, op, &rel.Shared)
-	rel.CanHaveSideEffects = true
-	rel.CanMutate = true
-
-	// Output Columns
-	// --------------
-	rel.OutputCols = op.Columns.ToSet()
-
-	// Not Null Columns
-	// ----------------
-	// All columns are assumed to be nullable.
-
-	// Outer Columns
-	// -------------
-	// No outer columns.
-
-	// Functional Dependencies
-	// -----------------------
-	// None.
-
-	// Cardinality
-	// -----------
-	// Any.
-	rel.Cardinality = props.AnyCardinality
-
-	// Statistics
-	// ----------
-	if !b.disableStats {
-		b.sb.buildUnknown(rel)
-	}
-}
-
 func (b *logicalPropsBuilder) buildFakeRelProps(fake *FakeRelExpr, rel *props.Relational) {
 	*rel = *fake.Props
 }

pkg/sql/opt/ops/statement.opt

@@ -90,3 +90,36 @@ define OpaqueRelPrivate {
     Columns ColList
     Metadata OpaqueMetadata 
 }
+
+# AlterTableSplit represents an `ALTER TABLE/INDEX .. SPLIT AT ..` statement.
+[Relational, DDL]
+define AlterTableSplit {
+    # The input expression provides values for the index columns (or a prefix of
+    # them).
+    Input RelExpr
+
+    # Expiration is a string scalar that indicates a timestamp after which the
+    # ranges are eligible for automatic merging (or Null if there is no
+    # expiration).
+    Expiration ScalarExpr
+
+    _ AlterTableSplitPrivate
+}
+
+[Private]
+define AlterTableSplitPrivate {
+    # Table identifies the table to alter. It is an id that can be passed to
+    # the Metadata.Table method in order to fetch cat.Table metadata.
+    Table TableID
+
+    # Index identifies the index to scan (whether primary or secondary). It
+    # can be passed to the cat.Table.Index(i int) method in order to fetch the
+    # cat.Index metadata.
+    Index int
+
+    # Props stores the required physical properties for the enclosed expression.
+    Props PhysProps
+
+    # Columns stores the column IDs for the statement result columns.
+    Columns ColList
+}