Golang QualifiedName.Database方法代码示例

// getTableID retrieves the table ID for the specified table. It uses the
// descriptor cache to perform lookups, falling back to the KV store when
// necessary.
func (p *planner) getTableID(qname *parser.QualifiedName) (ID, *roachpb.Error) {
	if err := qname.NormalizeTableName(p.session.Database); err != nil {
		return 0, roachpb.NewError(err)
	}

	dbID, pErr := p.getDatabaseID(qname.Database())
	if pErr != nil {
		return 0, pErr
	}

	// Lookup the ID of the table in the cache. The use of the cache might cause
	// the usage of a recently renamed table, but that's a race that could occur
	// anyways.
	nameKey := tableKey{dbID, qname.Table()}
	key := nameKey.Key()
	if nameVal := p.systemConfig.GetValue(key); nameVal != nil {
		id, err := nameVal.GetInt()
		return ID(id), roachpb.NewError(err)
	}

	gr, pErr := p.txn.Get(key)
	if pErr != nil {
		return 0, pErr
	}
	if !gr.Exists() {
		return 0, roachpb.NewErrorf("table %q does not exist", nameKey.Name())
	}
	return ID(gr.ValueInt()), nil
}

func (s *Server) getTableDesc(database string, qname parser.QualifiedName) (
	*structured.TableDescriptor, error) {
	var err error
	qname, err = s.normalizeTableName(database, qname)
	if err != nil {
		return nil, err
	}
	dbID, err := s.lookupDatabase(qname.Database())
	if err != nil {
		return nil, err
	}
	gr, err := s.db.Get(keys.MakeNameMetadataKey(dbID, qname.Table()))
	if err != nil {
		return nil, err
	}
	if !gr.Exists() {
		return nil, fmt.Errorf("table \"%s\" does not exist", qname)
	}
	descKey := gr.ValueBytes()
	desc := structured.TableDescriptor{}
	if err := s.db.GetProto(descKey, &desc); err != nil {
		return nil, err
	}
	if err := desc.Validate(); err != nil {
		return nil, err
	}
	return &desc, nil
}

// getTableLease acquires a lease for the specified table. The lease will be
// released when the planner closes.
func (p *planner) getTableLease(qname *parser.QualifiedName) (*TableDescriptor, *roachpb.Error) {
	if err := qname.NormalizeTableName(p.session.Database); err != nil {
		return nil, roachpb.NewError(err)
	}

	if qname.Database() == systemDB.Name || 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.
		return p.getTableDesc(qname)
	}

	tableID, pErr := p.getTableID(qname)
	if pErr != nil {
		return nil, pErr
	}

	if p.leases == nil {
		p.leases = make(map[ID]*LeaseState)
	}

	lease, ok := p.leases[tableID]
	if !ok {
		var pErr *roachpb.Error
		lease, pErr = p.leaseMgr.Acquire(p.txn, tableID, 0)
		if pErr != nil {
			return nil, pErr
		}
		p.leases[tableID] = lease
	}

	return proto.Clone(&lease.TableDescriptor).(*TableDescriptor), nil
}

// getTableID retrieves the table ID for the specified table. It uses the
// descriptor cache to perform lookups, falling back to the KV store when
// necessary.
func (p *planner) getTableID(qname *parser.QualifiedName) (sqlbase.ID, error) {
	if err := qname.NormalizeTableName(p.session.Database); err != nil {
		return 0, err
	}

	dbID, err := p.getDatabaseID(qname.Database())
	if err != nil {
		return 0, err
	}

	// Lookup the ID of the table in the cache. The use of the cache might cause
	// the usage of a recently renamed table, but that's a race that could occur
	// anyways.
	// TODO(andrei): remove the used of p.systemConfig as a cache for table names,
	// replace it with using the leases for resolving names, and do away with any
	// races due to renames. We'll probably have to rewrite renames to perform
	// an async schema change.
	nameKey := tableKey{dbID, qname.Table()}
	key := nameKey.Key()
	if nameVal := p.systemConfig.GetValue(key); nameVal != nil {
		id, err := nameVal.GetInt()
		return sqlbase.ID(id), err
	}

	gr, err := p.txn.Get(key)
	if err != nil {
		return 0, err
	}
	if !gr.Exists() {
		return 0, tableDoesNotExistError(qname.String())
	}
	return sqlbase.ID(gr.ValueInt()), nil
}

// getTableID retrieves the table ID for the specified table. It uses the
// descriptor cache to perform lookups, falling back to the KV store when
// necessary.
func (p *planner) getTableID(qname *parser.QualifiedName) (ID, error) {
	if err := qname.NormalizeTableName(p.session.Database); err != nil {
		return 0, err
	}

	// Lookup the database in the cache first, falling back to the KV store if it
	// isn't present. The cache might cause the usage of a recently renamed
	// database, but that's a race that could occur anyways.
	dbDesc, err := p.getCachedDatabaseDesc(qname.Database())
	if err != nil {
		dbDesc, err = p.getDatabaseDesc(qname.Database())
		if err != nil {
			return 0, err
		}
	}

	// Lookup the ID of the table in the cache. The use of the cache might cause
	// the usage of a recently renamed table, but that's a race that could occur
	// anyways.
	nameKey := tableKey{dbDesc.ID, qname.Table()}
	key := nameKey.Key()
	if nameVal := p.systemConfig.GetValue(key); nameVal != nil {
		id, err := nameVal.GetInt()
		return ID(id), err
	}

	gr, err := p.txn.Get(key)
	if err != nil {
		return 0, err
	}
	if !gr.Exists() {
		return 0, fmt.Errorf("table %q does not exist", nameKey.Name())
	}
	return ID(gr.ValueInt()), nil
}

// getTableLease implements the SchemaAccessor interface.
func (p *planner) getTableLease(qname *parser.QualifiedName) (*sqlbase.TableDescriptor, error) {
	if log.V(2) {
		log.Infof("planner acquiring lease on table %q", qname)
	}
	if err := qname.NormalizeTableName(p.session.Database); err != nil {
		return nil, err
	}

	if qname.Database() == sqlbase.SystemDB.Name || 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.
		return p.mustGetTableDesc(qname)
	}

	dbID, err := p.getDatabaseID(qname.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 sqlbase.NormalizeName(l.Name) == sqlbase.NormalizeName(qname.Table()) &&
			l.ParentID == dbID {
			lease = l
			if log.V(2) {
				log.Infof("found lease in planner cache for table %q", qname)
			}
			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, qname.Table())
		if err != nil {
			if err == errDescriptorNotFound {
				// Transform the descriptor error into an error that references the
				// table's name.
				return nil, sqlbase.NewUndefinedTableError(qname.String())
			}
			return nil, err
		}
		p.leases = append(p.leases, lease)
		// 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
}

// getTableLease acquires a lease for the specified table. The lease will be
// released when the planner closes. Note that a shallow copy of the table
// descriptor is returned. It is safe to mutate fields of the returned
// descriptor, but the values those fields point to should not be modified.
func (p *planner) getTableLease(qname *parser.QualifiedName) (sqlbase.TableDescriptor, error) {
	if err := qname.NormalizeTableName(p.session.Database); err != nil {
		return sqlbase.TableDescriptor{}, err
	}

	if qname.Database() == sqlbase.SystemDB.Name || 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.
		desc, err := p.getTableDesc(qname)
		if err != nil {
			return sqlbase.TableDescriptor{}, err
		}
		if desc == nil {
			return sqlbase.TableDescriptor{}, tableDoesNotExistError(qname.String())
		}
		return *desc, nil
	}

	tableID, err := p.getTableID(qname)
	if err != nil {
		return sqlbase.TableDescriptor{}, err
	}

	var lease *LeaseState
	var commitBy time.Time
	for _, l := range p.leases {
		commitBy = updateCommitBy(commitBy, l)
		if l.TableDescriptor.ID == tableID {
			lease = l
		}
	}
	if lease == nil {
		var err error
		lease, err = p.leaseMgr.Acquire(p.txn, tableID, 0)
		if err != nil {
			if _, ok := err.(*roachpb.DescriptorNotFoundError); ok {
				// Transform the descriptor error into an error that references the
				// table's name.
				return sqlbase.TableDescriptor{}, tableDoesNotExistError(qname.String())
			}
			return sqlbase.TableDescriptor{}, err
		}
		p.leases = append(p.leases, lease)
		commitBy = updateCommitBy(commitBy, lease)
	}
	p.txn.SetDeadline(roachpb.Timestamp{WallTime: commitBy.UnixNano()})
	return lease.TableDescriptor, nil
}

func (p *planner) getTableDesc(qname *parser.QualifiedName) (*TableDescriptor, error) {
	if err := qname.NormalizeTableName(p.session.Database); err != nil {
		return nil, err
	}
	dbDesc, err := p.getDatabaseDesc(qname.Database())
	if err != nil {
		return nil, err
	}

	desc := TableDescriptor{}
	if err := p.getDescriptor(tableKey{dbDesc.ID, qname.Table()}, &desc); err != nil {
		return nil, err
	}
	return &desc, nil
}

func (p *planner) getTableDesc(qname *parser.QualifiedName) (TableDescriptor, *roachpb.Error) {
	if err := qname.NormalizeTableName(p.session.Database); err != nil {
		return TableDescriptor{}, roachpb.NewError(err)
	}
	dbDesc, pErr := p.getDatabaseDesc(qname.Database())
	if pErr != nil {
		return TableDescriptor{}, pErr
	}

	desc := TableDescriptor{}
	if pErr := p.getDescriptor(tableKey{dbDesc.ID, qname.Table()}, &desc); pErr != nil {
		return TableDescriptor{}, pErr
	}
	return desc, nil
}

func (p *planner) getTableDesc(qname *parser.QualifiedName) (
	*structured.TableDescriptor, error) {
	if err := p.normalizeTableName(qname); err != nil {
		return nil, err
	}
	dbDesc, err := p.getDatabaseDesc(qname.Database())
	if err != nil {
		return nil, err
	}

	nameKey := keys.MakeNameMetadataKey(dbDesc.ID, qname.Table())
	desc := structured.TableDescriptor{}
	if err := p.getDescriptor(nameKey, &desc); err != nil {
		return nil, err
	}
	return &desc, nil
}

// getTableID retrieves the table ID for the specified table.
func getTableID(p *planner, qname *parser.QualifiedName) (sqlbase.ID, error) {
	if err := qname.NormalizeTableName(p.session.Database); err != nil {
		return 0, err
	}

	dbID, err := p.getDatabaseID(qname.Database())
	if err != nil {
		return 0, err
	}

	nameKey := tableKey{dbID, qname.Table()}
	key := nameKey.Key()
	gr, err := p.txn.Get(key)
	if err != nil {
		return 0, err
	}
	if !gr.Exists() {
		return 0, sqlbase.NewUndefinedTableError(qname.String())
	}
	return sqlbase.ID(gr.ValueInt()), nil
}

// getTableLease acquires a lease for the specified table. The lease will be
// released when the planner closes. Note that a shallow copy of the table
// descriptor is returned. It is safe to mutate fields of the returned
// descriptor, but the values those fields point to should not be modified.
//
// TODO(pmattis): Return a TableDesriptor value instead of a pointer.
func (p *planner) getTableLease(qname *parser.QualifiedName) (*TableDescriptor, *roachpb.Error) {
	if err := qname.NormalizeTableName(p.session.Database); err != nil {
		return nil, roachpb.NewError(err)
	}

	if qname.Database() == systemDB.Name || 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.
		return p.getTableDesc(qname)
	}

	tableID, pErr := p.getTableID(qname)
	if pErr != nil {
		return nil, pErr
	}

	var lease *LeaseState
	found := false
	for _, lease = range p.leases {
		if lease.TableDescriptor.ID == tableID {
			found = true
			break
		}
	}
	if !found {
		var pErr *roachpb.Error
		lease, pErr = p.leaseMgr.Acquire(p.txn, tableID, 0)
		if pErr != nil {
			return nil, pErr
		}
		p.leases = append(p.leases, lease)
	}

	desc := &TableDescriptor{}
	*desc = lease.TableDescriptor
	return desc, nil
}

// getTableDesc implements the SchemaAccessor interface.
func (p *planner) getTableDesc(qname *parser.QualifiedName) (*sqlbase.TableDescriptor, error) {
	if err := qname.NormalizeTableName(p.session.Database); err != nil {
		return nil, err
	}
	dbDesc, err := p.getDatabaseDesc(qname.Database())
	if err != nil {
		return nil, err
	}
	if dbDesc == nil {
		return nil, sqlbase.NewUndefinedDatabaseError(qname.Database())
	}

	desc := sqlbase.TableDescriptor{}
	found, err := p.getDescriptor(tableKey{parentID: dbDesc.ID, name: qname.Table()}, &desc)
	if err != nil {
		return nil, err
	}
	if !found {
		return nil, nil
	}
	return &desc, nil
}

// getCachedTableDesc looks for a table descriptor in the descriptor cache.
// Looks up the database descriptor, followed by the table descriptor.
//
// Returns: the table descriptor, whether it comes from the cache, and an error.
func (p *planner) getCachedTableDesc(qname *parser.QualifiedName) (*TableDescriptor, bool, error) {
	if err := qname.NormalizeTableName(p.session.Database); err != nil {
		return nil, false, err
	}
	dbDesc, cached, err := p.getCachedDatabaseDesc(qname.Database())
	if err != nil {
		return nil, false, err
	}

	desc := &TableDescriptor{}
	// Only attempt cached lookup if the database descriptor was found in the cache.
	if cached {
		if err := p.getCachedDescriptor(tableKey{dbDesc.ID, qname.Table()}, desc); err == nil {
			return desc, true, nil
		}
		// Problem, or not found in the cache: fall back on KV lookup.
	}

	if err := p.getDescriptor(tableKey{dbDesc.ID, qname.Table()}, desc); err != nil {
		return nil, false, err
	}
	return desc, false, nil
}