sql: Support SELECT FOR UPDATE SQL syntax

Update the parser to recognize the SELECT ... FOR UPDATE SQL syntax. Update the SQL layer so scan nodes in the query plan are flagged as lockForUpdate if the SELECT ... FOR UPDATE syntax is used. If a scan node with lockForUpdate is encountered during plan execution, return an error so the user knows that SELECT ... FOR UPDATE is not yet fully supported. This is the first of several commits/PRs needed to support SELECT ... FOR UPDATE. Future commits will implement the changes required at the KV layer, connect the two layers with changes to the KV api, and eliminate the temporary error message introduced in this commit. See PR cockroachdb#19577 for the RFC, and Issue cockroachdb#6583.
rytaft · Oct 30, 2017 · ccb6904 · ccb6904
1 parent 818c668
commit ccb6904
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Showing 26 changed files with 7,177 additions and 6,963 deletions.
diff --git a/pkg/sql/check.go b/pkg/sql/check.go
@@ -153,7 +153,8 @@ func (p *planner) validateCheckExpr(
 	// use the tableDesc we have, but this is a rare operation and be benefit
 	// would be marginal compared to the work of the actual query, so the added
 	// complexity seems unjustified.
-	rows, err := p.SelectClause(ctx, sel, nil, lim, nil, publicColumns)
+	rows, err := p.SelectClause(ctx, sel, nil /* orderBy */, lim, false, /* lockForUpdate */
+		nil /* desiredTypes */, publicColumns)
 	if err != nil {
 		return err
 	}

diff --git a/pkg/sql/data_source.go b/pkg/sql/data_source.go
@@ -241,7 +241,10 @@ func newSourceInfoForSingleTable(
 
 // getSources combines zero or more FROM sources into cross-joins.
 func (p *planner) getSources(
-	ctx context.Context, sources []parser.TableExpr, scanVisibility scanVisibility,
+	ctx context.Context,
+	sources []parser.TableExpr,
+	scanVisibility scanVisibility,
+	lockForUpdate bool,
 ) (planDataSource, error) {
 	switch len(sources) {
 	case 0:
@@ -252,14 +255,14 @@ func (p *planner) getSources(
 		}, nil
 
 	case 1:
-		return p.getDataSource(ctx, sources[0], nil, scanVisibility)
+		return p.getDataSource(ctx, sources[0], nil /* hints */, scanVisibility, lockForUpdate)
 
 	default:
-		left, err := p.getDataSource(ctx, sources[0], nil, scanVisibility)
+		left, err := p.getDataSource(ctx, sources[0], nil /* hints */, scanVisibility, lockForUpdate)
 		if err != nil {
 			return planDataSource{}, err
 		}
-		right, err := p.getSources(ctx, sources[1:], scanVisibility)
+		right, err := p.getSources(ctx, sources[1:], scanVisibility, lockForUpdate)
 		if err != nil {
 			return planDataSource{}, err
 		}
@@ -334,7 +337,7 @@ func (p *planner) getVirtualDataSource(
 func (p *planner) getDataSourceAsOneColumn(
 	ctx context.Context, src *parser.FuncExpr,
 ) (planDataSource, error) {
-	ds, err := p.getDataSource(ctx, src, nil, publicColumns)
+	ds, err := p.getDataSource(ctx, src, nil /* hints */, publicColumns, false /* lockForUpdate */)
 	if err != nil {
 		return ds, err
 	}
@@ -369,6 +372,7 @@ func (p *planner) getDataSource(
 	src parser.TableExpr,
 	hints *parser.IndexHints,
 	scanVisibility scanVisibility,
+	lockForUpdate bool,
 ) (planDataSource, error) {
 	switch t := src.(type) {
 	case *parser.NormalizableTableName:
@@ -386,7 +390,7 @@ func (p *planner) getDataSource(
 		if foundVirtual {
 			return ds, nil
 		}
-		return p.getTableScanOrViewPlan(ctx, tn, hints, scanVisibility)
+		return p.getTableScanOrViewPlan(ctx, tn, hints, scanVisibility, lockForUpdate)
 
 	case *parser.FuncExpr:
 		return p.getGeneratorPlan(ctx, t)
@@ -396,11 +400,11 @@ func (p *planner) getDataSource(
 
 	case *parser.JoinTableExpr:
 		// Joins: two sources.
-		left, err := p.getDataSource(ctx, t.Left, nil, scanVisibility)
+		left, err := p.getDataSource(ctx, t.Left, nil /* hints */, scanVisibility, lockForUpdate)
 		if err != nil {
 			return left, err
 		}
-		right, err := p.getDataSource(ctx, t.Right, nil, scanVisibility)
+		right, err := p.getDataSource(ctx, t.Right, nil /* hints */, scanVisibility, lockForUpdate)
 		if err != nil {
 			return right, err
 		}
@@ -417,10 +421,10 @@ func (p *planner) getDataSource(
 		}, nil
 
 	case *parser.ParenTableExpr:
-		return p.getDataSource(ctx, t.Expr, hints, scanVisibility)
+		return p.getDataSource(ctx, t.Expr, hints, scanVisibility, lockForUpdate)
 
 	case *parser.TableRef:
-		return p.getTableScanByRef(ctx, t, hints, scanVisibility)
+		return p.getTableScanByRef(ctx, t, hints, scanVisibility, lockForUpdate)
 
 	case *parser.AliasedTableExpr:
 		// Alias clause: source AS alias(cols...)
@@ -429,7 +433,7 @@ func (p *planner) getDataSource(
 			hints = t.Hints
 		}
 
-		src, err := p.getDataSource(ctx, t.Expr, hints, scanVisibility)
+		src, err := p.getDataSource(ctx, t.Expr, hints, scanVisibility, lockForUpdate)
 		if err != nil {
 			return src, err
 		}
@@ -479,6 +483,7 @@ func (p *planner) getTableScanByRef(
 	tref *parser.TableRef,
 	hints *parser.IndexHints,
 	scanVisibility scanVisibility,
+	lockForUpdate bool,
 ) (planDataSource, error) {
 	desc, err := p.getTableDescByID(ctx, sqlbase.ID(tref.TableID))
 	if err != nil {
@@ -498,7 +503,7 @@ func (p *planner) getTableScanByRef(
 		DBNameOriginallyOmitted: true,
 	}
 
-	src, err := p.getPlanForDesc(ctx, desc, &tn, hints, scanVisibility, tref.Columns)
+	src, err := p.getPlanForDesc(ctx, desc, &tn, hints, scanVisibility, lockForUpdate, tref.Columns)
 	if err != nil {
 		return src, err
 	}
@@ -572,6 +577,7 @@ func (p *planner) getTableScanOrViewPlan(
 	tn *parser.TableName,
 	hints *parser.IndexHints,
 	scanVisibility scanVisibility,
+	lockForUpdate bool,
 ) (planDataSource, error) {
 	if tn.PrefixOriginallySpecified {
 		// Prefixes are currently only supported for virtual tables.
@@ -584,7 +590,7 @@ func (p *planner) getTableScanOrViewPlan(
 		return planDataSource{}, err
 	}
 
-	return p.getPlanForDesc(ctx, desc, tn, hints, scanVisibility, nil)
+	return p.getPlanForDesc(ctx, desc, tn, hints, scanVisibility, lockForUpdate, nil /* wantedColumns */)
 }
 
 func (p *planner) getTableDesc(
@@ -607,6 +613,7 @@ func (p *planner) getPlanForDesc(
 	tn *parser.TableName,
 	hints *parser.IndexHints,
 	scanVisibility scanVisibility,
+	lockForUpdate bool,
 	wantedColumns []parser.ColumnID,
 ) (planDataSource, error) {
 	if desc.IsView() {
@@ -625,6 +632,7 @@ func (p *planner) getPlanForDesc(
 	if err := scan.initTable(p, desc, hints, scanVisibility, wantedColumns); err != nil {
 		return planDataSource{}, err
 	}
+	scan.lockForUpdate = lockForUpdate
 
 	return planDataSource{
 		info: newSourceInfoForSingleTable(*tn, planColumns(scan)),

diff --git a/pkg/sql/delete.go b/pkg/sql/delete.go
@@ -95,7 +95,8 @@ func (p *planner) Delete(
 		Exprs: sqlbase.ColumnsSelectors(rd.FetchCols),
 		From:  &parser.From{Tables: []parser.TableExpr{n.Table}},
 		Where: n.Where,
-	}, nil, n.Limit, nil, publicAndNonPublicColumns)
+	}, nil /* orderBy */, n.Limit, false, /* lockForUpdate */
+		nil /* desiredTypes */, publicAndNonPublicColumns)
 	if err != nil {
 		return nil, err
 	}

diff --git a/pkg/sql/distsql_physical_planner.go b/pkg/sql/distsql_physical_planner.go
@@ -653,8 +653,9 @@ func initTableReaderSpec(
 	n *scanNode,
 ) (distsqlrun.TableReaderSpec, distsqlrun.PostProcessSpec, error) {
 	s := distsqlrun.TableReaderSpec{
-		Table:   *n.desc,
-		Reverse: n.reverse,
+		Table:         *n.desc,
+		Reverse:       n.reverse,
+		LockForUpdate: n.lockForUpdate,
 	}
 	if n.index != &n.desc.PrimaryIndex {
 		for i := range n.desc.Indexes {
@@ -1785,8 +1786,9 @@ ColLoop:
 	}
 
 	joinReaderSpec := distsqlrun.JoinReaderSpec{
-		Table:    *n.index.desc,
-		IndexIdx: 0,
+		Table:         *n.index.desc,
+		IndexIdx:      0,
+		LockForUpdate: n.index.lockForUpdate,
 	}
 
 	post := distsqlrun.PostProcessSpec{

diff --git a/pkg/sql/distsqlrun/columnbackfiller.go b/pkg/sql/distsqlrun/columnbackfiller.go
@@ -117,8 +117,8 @@ func (cb *columnBackfiller) init() error {
 		colIdxMap[c.ID] = i
 	}
 	return cb.fetcher.Init(
-		&desc, colIdxMap, &desc.PrimaryIndex, false, false, desc.Columns,
-		valNeededForCol, false, &cb.alloc,
+		&desc, colIdxMap, &desc.PrimaryIndex, false /* reverse */, false, /* lockForUpdate */
+		false /* isSecondaryIndex */, desc.Columns, valNeededForCol, false /* returnRangeInfo */, &cb.alloc,
 	)
 }
 

diff --git a/pkg/sql/distsqlrun/indexbackfiller.go b/pkg/sql/distsqlrun/indexbackfiller.go
@@ -107,8 +107,8 @@ func (ib *indexBackfiller) init() error {
 	}
 
 	return ib.fetcher.Init(
-		&desc, ib.colIdxMap, &desc.PrimaryIndex, false, false, cols,
-		valNeededForCol, false, &ib.alloc,
+		&desc, ib.colIdxMap, &desc.PrimaryIndex, false /* reverse */, false, /* lockForUpdate */
+		false /* isSecondaryIndex */, cols, valNeededForCol, false /* returnRangeInfo */, &ib.alloc,
 	)
 }
 

diff --git a/pkg/sql/distsqlrun/joinreader.go b/pkg/sql/distsqlrun/joinreader.go
@@ -79,7 +79,7 @@ func newJoinReader(
 	var err error
 	jr.index, _, err = initRowFetcher(
 		&jr.fetcher, &jr.desc, int(spec.IndexIdx), false, /* reverse */
-		jr.out.neededColumns(), &jr.alloc,
+		spec.LockForUpdate, jr.out.neededColumns(), &jr.alloc,
 	)
 	if err != nil {
 		return nil, err