// newSourceInfoForSingleTable creates a simple dataSourceInfo
// which maps the same tableAlias to all columns.
func newSourceInfoForSingleTable(tn parser.TableName, columns ResultColumns) *dataSourceInfo {
norm := tn.NormalizedTableName()
return &dataSourceInfo{
sourceColumns: columns,
sourceAliases: sourceAliases{norm: fillColumnRange(0, len(columns)-1)},
}
}
func getTableOrViewDesc(
txn *client.Txn, vt VirtualTabler, tn *parser.TableName,
) (*sqlbase.TableDescriptor, error) {
virtual, err := vt.getVirtualTableDesc(tn)
if err != nil || virtual != nil {
if _, ok := err.(*sqlbase.ErrUndefinedTable); ok {
return nil, nil
}
return virtual, err
}
dbDesc, err := MustGetDatabaseDesc(txn, vt, tn.Database())
if err != nil {
return nil, err
}
desc := sqlbase.TableDescriptor{}
found, err := getDescriptor(txn, tableKey{parentID: dbDesc.ID, name: tn.Table()}, &desc)
if err != nil {
return nil, err
}
if !found {
return nil, nil
}
return &desc, nil
}
// getViewDesc implements the SchemaAccessor interface.
func (p *planner) getViewDesc(tn *parser.TableName) (*sqlbase.TableDescriptor, error) {
desc, err := p.getTableOrViewDesc(tn)
if err != nil {
return desc, err
}
if desc != nil && !desc.IsView() {
return nil, sqlbase.NewWrongObjectTypeError(tn.String(), "view")
}
return desc, nil
}
// getQualifiedTableName returns the database-qualified name of the table
// or view represented by the provided descriptor.
func (p *planner) getQualifiedTableName(desc *sqlbase.TableDescriptor) (string, error) {
dbDesc, err := sqlbase.GetDatabaseDescFromID(p.txn, desc.ParentID)
if err != nil {
return "", err
}
tbName := parser.TableName{
DatabaseName: parser.Name(dbDesc.Name),
TableName: parser.Name(desc.Name),
}
return tbName.String(), nil
}
// getVirtualTableEntry checks if the provided name matches a virtual database/table
// pair. The function will return the table's virtual table entry if the name matches
// a specific table. It will return an error if the name references a virtual database
// but the table is non-existent.
func (vs *virtualSchemaHolder) getVirtualTableEntry(
tn *parser.TableName,
) (virtualTableEntry, error) {
if db, ok := vs.getVirtualSchemaEntry(tn.DatabaseName.Normalize()); ok {
if t, ok := db.tables[tn.TableName.Normalize()]; ok {
return t, nil
}
return virtualTableEntry{}, sqlbase.NewUndefinedTableError(tn.String())
}
return virtualTableEntry{}, nil
}
// getTableDesc implements the SchemaAccessor interface.
func getTableDesc(
txn *client.Txn, vt VirtualTabler, tn *parser.TableName,
) (*sqlbase.TableDescriptor, error) {
desc, err := getTableOrViewDesc(txn, vt, tn)
if err != nil {
return desc, err
}
if desc != nil && !desc.IsTable() {
return nil, sqlbase.NewWrongObjectTypeError(tn.String(), "table")
}
return desc, nil
}
// mustGetViewDesc implements the SchemaAccessor interface.
func (p *planner) mustGetViewDesc(tn *parser.TableName) (*sqlbase.TableDescriptor, error) {
desc, err := p.getViewDesc(tn)
if err != nil {
return nil, err
}
if desc == nil {
return nil, sqlbase.NewUndefinedViewError(tn.String())
}
if err := filterTableState(desc); err != nil {
return nil, err
}
return desc, nil
}
func mustGetTableDesc(
txn *client.Txn, vt VirtualTabler, tn *parser.TableName,
) (*sqlbase.TableDescriptor, error) {
desc, err := getTableDesc(txn, vt, tn)
if err != nil {
return nil, err
}
if desc == nil {
return nil, sqlbase.NewUndefinedTableError(tn.String())
}
if err := filterTableState(desc); err != nil {
return nil, err
}
return desc, nil
}
// checkDatabaseName checks whether the given TableName is unambiguous
// within this source and if it is, qualifies the missing database name.
func (src *dataSourceInfo) checkDatabaseName(tn parser.TableName) (parser.TableName, error) {
found := false
if tn.DatabaseName == "" {
// No database name yet. Try to find one.
for name := range src.sourceAliases {
if name.TableName == tn.TableName {
if found {
return parser.TableName{}, fmt.Errorf("ambiguous source name: %q", tn.TableName)
}
tn.DatabaseName = name.DatabaseName
found = true
}
}
if !found {
return parser.TableName{}, fmt.Errorf("source name %q not found in FROM clause", tn.TableName)
}
return tn, nil
}
// Database given. Check that the name is unambiguous.
if _, ok := src.sourceAliases[tn]; ok {
if found {
return parser.TableName{}, fmt.Errorf("ambiguous source name: %q (within database %q)",
tn.TableName, tn.DatabaseName)
}
found = true
}
if !found {
return parser.TableName{}, fmt.Errorf("table %q not selected in FROM clause", &tn)
}
return tn, nil
}
// checkDatabaseName checks whether the given TableName is unambiguous
// within this source and if it is, qualifies the missing database name.
func (src *dataSourceInfo) checkDatabaseName(tn parser.TableName) (parser.TableName, error) {
if tn.DatabaseName == "" {
// No database name yet. Try to find one.
found := false
for _, alias := range src.sourceAliases {
if alias.name.TableName == tn.TableName {
if found {
return parser.TableName{}, fmt.Errorf("ambiguous source name: %q", tn.TableName)
}
found = true
tn.DatabaseName = alias.name.DatabaseName
}
}
if !found {
return parser.TableName{}, fmt.Errorf("source name %q not found in FROM clause", tn.TableName)
}
return tn, nil
}
// Database given.
if _, found := src.sourceAliases.srcIdx(tn); !found {
return parser.TableName{}, fmt.Errorf("table %q not selected in FROM clause", &tn)
}
return tn, nil
}
// getTableID retrieves the table ID for the specified table.
func getTableID(p *planner, tn *parser.TableName) (sqlbase.ID, error) {
if err := tn.QualifyWithDatabase(p.session.Database); err != nil {
return 0, err
}
virtual, err := p.session.virtualSchemas.getVirtualTableDesc(tn)
if err != nil {
return 0, err
}
if virtual != nil {
return virtual.GetID(), nil
}
dbID, err := p.getDatabaseID(tn.Database())
if err != nil {
return 0, err
}
nameKey := tableKey{dbID, tn.Table()}
key := nameKey.Key()
gr, err := p.txn.Get(key)
if err != nil {
return 0, err
}
if !gr.Exists() {
return 0, sqlbase.NewUndefinedTableError(parser.AsString(tn))
}
return sqlbase.ID(gr.ValueInt()), nil
}
// getVirtualDataSource attempts to find a virtual table with the
// given name.
func (p *planner) getVirtualDataSource(tn *parser.TableName) (planDataSource, bool, error) {
virtual, err := p.session.virtualSchemas.getVirtualTableEntry(tn)
if err != nil {
return planDataSource{}, false, err
}
if virtual.desc != nil {
columns, constructor := virtual.getPlanInfo()
sourceName := parser.TableName{
TableName: parser.Name(virtual.desc.Name),
DatabaseName: tn.DatabaseName,
}
return planDataSource{
info: newSourceInfoForSingleTable(sourceName, columns),
plan: &delayedNode{
name: sourceName.String(),
columns: columns,
constructor: constructor,
},
}, true, nil
}
return planDataSource{}, false, nil
}
// getTableOrViewDesc implements the SchemaAccessor interface.
func (p *planner) getTableOrViewDesc(tn *parser.TableName) (*sqlbase.TableDescriptor, error) {
virtual, err := p.session.virtualSchemas.getVirtualTableDesc(tn)
if err != nil || virtual != nil {
if _, ok := err.(*sqlbase.ErrUndefinedTable); ok {
return nil, nil
}
return virtual, err
}
dbDesc, err := p.mustGetDatabaseDesc(tn.Database())
if err != nil {
return nil, err
}
desc := sqlbase.TableDescriptor{}
found, err := p.getDescriptor(tableKey{parentID: dbDesc.ID, name: tn.Table()}, &desc)
if err != nil {
return nil, err
}
if !found {
return nil, nil
}
return &desc, nil
}
// expandStar returns the array of column metadata and name
// expressions that correspond to the expansion of a star.
func (src *dataSourceInfo) expandStar(
v parser.VarName, ivarHelper parser.IndexedVarHelper,
) (columns ResultColumns, exprs []parser.TypedExpr, err error) {
if len(src.sourceColumns) == 0 {
return nil, nil, fmt.Errorf("cannot use %q without a FROM clause", v)
}
colSel := func(idx int) {
col := src.sourceColumns[idx]
if !col.hidden {
ivar := ivarHelper.IndexedVar(idx)
columns = append(columns, ResultColumn{Name: col.Name, Typ: ivar.ResolvedType()})
exprs = append(exprs, ivar)
}
}
tableName := parser.TableName{}
if a, ok := v.(*parser.AllColumnsSelector); ok {
tableName = a.TableName
}
if tableName.Table() == "" {
for i := 0; i < len(src.sourceColumns); i++ {
colSel(i)
}
} else {
norm := tableName.NormalizedTableName()
qualifiedTn, err := src.checkDatabaseName(norm)
if err != nil {
return nil, nil, err
}
colRange, ok := src.sourceAliases[qualifiedTn]
if !ok {
return nil, nil, fmt.Errorf("table %q not found", tableName.String())
}
for _, i := range colRange {
colSel(i)
}
}
return columns, exprs, nil
}
// getDataSource builds a planDataSource from a single data source clause
// (TableExpr) in a SelectClause.
func (p *planner) getDataSource(
src parser.TableExpr, hints *parser.IndexHints, scanVisibility scanVisibility,
) (planDataSource, error) {
switch t := src.(type) {
case *parser.NormalizableTableName:
// Usual case: a table.
tn, err := p.QualifyWithDatabase(t)
if err != nil {
return planDataSource{}, err
}
// Is this perhaps a name for a virtual table?
ds, foundVirtual, err := p.getVirtualDataSource(tn)
if err != nil {
return planDataSource{}, err
}
if foundVirtual {
return ds, nil
}
return p.getTableScanOrViewPlan(tn, hints, scanVisibility)
case *parser.Subquery:
return p.getSubqueryPlan(t.Select, nil)
case *parser.JoinTableExpr:
// Joins: two sources.
left, err := p.getDataSource(t.Left, nil, scanVisibility)
if err != nil {
return left, err
}
right, err := p.getDataSource(t.Right, nil, scanVisibility)
if err != nil {
return right, err
}
return p.makeJoin(t.Join, left, right, t.Cond)
case *parser.ParenTableExpr:
return p.getDataSource(t.Expr, hints, scanVisibility)
case *parser.AliasedTableExpr:
// Alias clause: source AS alias(cols...)
src, err := p.getDataSource(t.Expr, t.Hints, scanVisibility)
if err != nil {
return src, err
}
var tableAlias parser.TableName
if t.As.Alias != "" {
// If an alias was specified, use that.
tableAlias.TableName = parser.Name(t.As.Alias.Normalize())
src.info.sourceAliases = sourceAliases{
tableAlias: fillColumnRange(0, len(src.info.sourceColumns)-1),
}
}
colAlias := t.As.Cols
if len(colAlias) > 0 {
// Make a copy of the slice since we are about to modify the contents.
src.info.sourceColumns = append(ResultColumns(nil), src.info.sourceColumns...)
// The column aliases can only refer to explicit columns.
for colIdx, aliasIdx := 0, 0; aliasIdx < len(colAlias); colIdx++ {
if colIdx >= len(src.info.sourceColumns) {
var srcName string
if tableAlias.DatabaseName != "" {
srcName = tableAlias.String()
} else {
srcName = tableAlias.TableName.String()
}
return planDataSource{}, errors.Errorf(
"source %q has %d columns available but %d columns specified",
srcName, aliasIdx, len(colAlias))
}
if src.info.sourceColumns[colIdx].hidden {
continue
}
src.info.sourceColumns[colIdx].Name = string(colAlias[aliasIdx])
aliasIdx++
}
}
return src, nil
default:
return planDataSource{}, errors.Errorf("unsupported FROM type %T", src)
}
}
// getTableLease implements the SchemaAccessor interface.
func (p *planner) getTableLease(tn *parser.TableName) (*sqlbase.TableDescriptor, error) {
if log.V(2) {
log.Infof(p.ctx(), "planner acquiring lease on table '%s'", tn)
}
isSystemDB := tn.Database() == sqlbase.SystemDB.Name
isVirtualDB := p.session.virtualSchemas.isVirtualDatabase(tn.Database())
if isSystemDB || isVirtualDB || testDisableTableLeases {
// We don't go through the normal lease mechanism for:
// - system tables. The system.lease and system.descriptor table, in
// particular, are problematic because they are used for acquiring
// leases itself, creating a chicken&egg problem.
// - virtual tables. These tables' descriptors are not persisted,
// so they cannot be leased. Instead, we simply return the static
// descriptor and rely on the immutability privileges set on the
// descriptors to cause upper layers to reject mutations statements.
tbl, err := p.mustGetTableDesc(tn)
if err != nil {
return nil, err
}
if err := filterTableState(tbl); err != nil {
return nil, err
}
return tbl, nil
}
dbID, err := p.getDatabaseID(tn.Database())
if err != nil {
return nil, err
}
// First, look to see if we already have a lease for this table.
// This ensures that, once a SQL transaction resolved name N to id X, it will
// continue to use N to refer to X even if N is renamed during the
// transaction.
var lease *LeaseState
for _, l := range p.leases {
if parser.ReNormalizeName(l.Name) == tn.TableName.Normalize() &&
l.ParentID == dbID {
lease = l
if log.V(2) {
log.Infof(p.ctx(), "found lease in planner cache for table '%s'", tn)
}
break
}
}
// If we didn't find a lease or the lease is about to expire, acquire one.
if lease == nil || p.removeLeaseIfExpiring(lease) {
var err error
lease, err = p.leaseMgr.AcquireByName(p.txn, dbID, tn.Table())
if err != nil {
if err == sqlbase.ErrDescriptorNotFound {
// Transform the descriptor error into an error that references the
// table's name.
return nil, sqlbase.NewUndefinedTableError(tn.String())
}
return nil, err
}
p.leases = append(p.leases, lease)
if log.V(2) {
log.Infof(p.ctx(), "added lease on table '%s' to planner cache", tn)
}
// If the lease we just acquired expires before the txn's deadline, reduce
// the deadline.
p.txn.UpdateDeadlineMaybe(hlc.Timestamp{WallTime: lease.Expiration().UnixNano()})
}
return &lease.TableDescriptor, nil
}
// findColumn looks up the column specified by a ColumnItem. The
// function returns the index of the source in the multiSourceInfo
// array and the column index for the column array of that
// source. Returns invalid indices and an error if the source is not
// found or the name is ambiguous.
func (sources multiSourceInfo) findColumn(c *parser.ColumnItem) (srcIdx int, colIdx int, err error) {
if len(c.Selector) > 0 {
return invalidSrcIdx, invalidColIdx, util.UnimplementedWithIssueErrorf(8318, "compound types not supported yet: %q", c)
}
colName := c.ColumnName.Normalize()
var tableName parser.TableName
if c.TableName.Table() != "" {
tableName = c.TableName.NormalizedTableName()
tn, err := sources.checkDatabaseName(tableName)
if err != nil {
return invalidSrcIdx, invalidColIdx, err
}
tableName = tn
// Propagate the discovered database name back to the original VarName.
// (to clarify the output of e.g. EXPLAIN)
c.TableName.DatabaseName = tableName.DatabaseName
}
colIdx = invalidColIdx
for iSrc, src := range sources {
findColHelper := func(src *dataSourceInfo, iSrc, srcIdx, colIdx int, idx int) (int, int, error) {
col := src.sourceColumns[idx]
if parser.ReNormalizeName(col.Name) == colName {
if colIdx != invalidColIdx {
return invalidSrcIdx, invalidColIdx, fmt.Errorf("column reference %q is ambiguous", c)
}
srcIdx = iSrc
colIdx = idx
}
return srcIdx, colIdx, nil
}
if tableName.Table() == "" {
for idx := 0; idx < len(src.sourceColumns); idx++ {
srcIdx, colIdx, err = findColHelper(src, iSrc, srcIdx, colIdx, idx)
if err != nil {
return srcIdx, colIdx, err
}
}
} else {
colRange, ok := src.sourceAliases[tableName]
if !ok {
// The data source "src" has no column for table tableName.
// Try again with the net one.
continue
}
for _, idx := range colRange {
srcIdx, colIdx, err = findColHelper(src, iSrc, srcIdx, colIdx, idx)
if err != nil {
return srcIdx, colIdx, err
}
}
}
}
if colIdx == invalidColIdx {
return invalidSrcIdx, invalidColIdx, fmt.Errorf("column name %q not found", c)
}
return srcIdx, colIdx, nil
}
// getDataSource builds a planDataSource from a single data source clause
// (TableExpr) in a SelectClause.
func (p *planner) getDataSource(
src parser.TableExpr, hints *parser.IndexHints, scanVisibility scanVisibility,
) (planDataSource, error) {
switch t := src.(type) {
case *parser.NormalizableTableName:
// Usual case: a table.
tn, err := p.QualifyWithDatabase(t)
if err != nil {
return planDataSource{}, err
}
// Is this perhaps a name for a virtual table?
ds, foundVirtual, err := p.getVirtualDataSource(tn)
if err != nil {
return planDataSource{}, err
}
if foundVirtual {
return ds, nil
}
return p.getTableScanOrViewPlan(tn, hints, scanVisibility)
case *parser.FuncExpr:
return p.getGeneratorPlan(t)
case *parser.Subquery:
return p.getSubqueryPlan(t.Select, nil)
case *parser.JoinTableExpr:
// Joins: two sources.
left, err := p.getDataSource(t.Left, nil, scanVisibility)
if err != nil {
return left, err
}
right, err := p.getDataSource(t.Right, nil, scanVisibility)
if err != nil {
return right, err
}
return p.makeJoin(t.Join, left, right, t.Cond)
case *parser.Explain:
plan, err := p.Explain(t, false)
if err != nil {
return planDataSource{}, err
}
return planDataSource{
info: newSourceInfoForSingleTable(anonymousTable, plan.Columns()),
plan: plan,
}, nil
case *parser.ParenTableExpr:
return p.getDataSource(t.Expr, hints, scanVisibility)
case *parser.AliasedTableExpr:
// Alias clause: source AS alias(cols...)
src, err := p.getDataSource(t.Expr, t.Hints, scanVisibility)
if err != nil {
return src, err
}
if t.Ordinality {
// The WITH ORDINALITY clause numbers the rows coming out of the
// data source. See the comments next to the definition of
// `ordinalityNode` in particular how this restricts
// optimizations.
src = p.wrapOrdinality(src)
}
var tableAlias parser.TableName
if t.As.Alias != "" {
// If an alias was specified, use that.
tableAlias.TableName = parser.Name(t.As.Alias.Normalize())
src.info.sourceAliases = sourceAliases{{
name: tableAlias,
columnRange: fillColumnRange(0, len(src.info.sourceColumns)-1),
}}
}
colAlias := t.As.Cols
if len(colAlias) > 0 {
// Make a copy of the slice since we are about to modify the contents.
src.info.sourceColumns = append(ResultColumns(nil), src.info.sourceColumns...)
// The column aliases can only refer to explicit columns.
for colIdx, aliasIdx := 0, 0; aliasIdx < len(colAlias); colIdx++ {
if colIdx >= len(src.info.sourceColumns) {
var srcName string
if tableAlias.DatabaseName != "" {
srcName = tableAlias.String()
} else {
srcName = tableAlias.TableName.String()
}
return planDataSource{}, errors.Errorf(
"source %q has %d columns available but %d columns specified",
srcName, aliasIdx, len(colAlias))
}
if src.info.sourceColumns[colIdx].hidden {
continue
}
src.info.sourceColumns[colIdx].Name = string(colAlias[aliasIdx])
aliasIdx++
}
}
return src, nil
default:
return planDataSource{}, errors.Errorf("unsupported FROM type %T", src)
}
}
