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
}
// 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
}
// 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
}
// 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
}