// deleteRow adds to the batch the kv operations necessary to delete a table row
// with the given values.
func (rd *rowDeleter) deleteRow(b *client.Batch, values []parser.Datum) error {
	if err := rd.fks.checkAll(values); err != nil {
		return err
	}

	primaryIndexKey, secondaryIndexEntries, err := rd.helper.encodeIndexes(rd.fetchColIDtoRowIndex, values)
	if err != nil {
		return err
	}

	for _, secondaryIndexEntry := range secondaryIndexEntries {
		if log.V(2) {
			log.Infof("Del %s", secondaryIndexEntry.Key)
		}
		b.Del(secondaryIndexEntry.Key)
	}

	// Delete the row.
	rd.startKey = roachpb.Key(primaryIndexKey)
	rd.endKey = roachpb.Key(encoding.EncodeNotNullDescending(primaryIndexKey))
	if log.V(2) {
		log.Infof("DelRange %s - %s", rd.startKey, rd.endKey)
	}
	b.DelRange(&rd.startKey, &rd.endKey, false)
	rd.startKey, rd.endKey = nil, nil

	return nil
}

// StoreData writes the supplied time series data to the cockroach server.
// Stored data will be sampled at the supplied resolution.
func (db *DB) StoreData(r Resolution, data []tspb.TimeSeriesData) error {
	var kvs []roachpb.KeyValue

	// Process data collection: data is converted to internal format, and a key
	// is generated for each internal message.
	for _, d := range data {
		idatas, err := d.ToInternal(r.KeyDuration(), r.SampleDuration())
		if err != nil {
			return err
		}
		for _, idata := range idatas {
			var value roachpb.Value
			if err := value.SetProto(&idata); err != nil {
				return err
			}
			kvs = append(kvs, roachpb.KeyValue{
				Key:   MakeDataKey(d.Name, d.Source, r, idata.StartTimestampNanos),
				Value: value,
			})
		}
	}

	// Send the individual internal merge requests.
	b := client.Batch{}
	for _, kv := range kvs {
		b.AddRawRequest(&roachpb.MergeRequest{
			Span: roachpb.Span{
				Key: kv.Key,
			},
			Value: kv.Value,
		})
	}

	return db.db.Run(&b)
}

// insertCPutFn is used by insertRow when conflicts should be respected.
// logValue is used for pretty printing.
func insertCPutFn(b *client.Batch, key *roachpb.Key, value *roachpb.Value) {
	// TODO(dan): We want do this V(2) log everywhere in sql. Consider making a
	// client.Batch wrapper instead of inlining it everywhere.
	if log.V(2) {
		log.InfofDepth(1, "CPut %s -> %s", *key, value.PrettyPrint())
	}
	b.CPut(key, value, nil)
}

// createDescriptor implements the DescriptorAccessor interface.
func (p *planner) createDescriptor(plainKey sqlbase.DescriptorKey, descriptor sqlbase.DescriptorProto, ifNotExists bool) (bool, error) {
	idKey := plainKey.Key()
	// Check whether idKey exists.
	gr, err := p.txn.Get(idKey)
	if err != nil {
		return false, err
	}

	if gr.Exists() {
		if ifNotExists {
			// Noop.
			return false, nil
		}
		// Key exists, but we don't want it to: error out.
		return false, fmt.Errorf("%s %q already exists", descriptor.TypeName(), plainKey.Name())
	}

	// Increment unique descriptor counter.
	if ir, err := p.txn.Inc(keys.DescIDGenerator, 1); err == nil {
		descriptor.SetID(sqlbase.ID(ir.ValueInt() - 1))
	} else {
		return false, err
	}

	// TODO(pmattis): The error currently returned below is likely going to be
	// difficult to interpret.
	//
	// TODO(pmattis): Need to handle if-not-exists here as well.
	//
	// TODO(pmattis): This is writing the namespace and descriptor table entries,
	// but not going through the normal INSERT logic and not performing a precise
	// mimicry. In particular, we're only writing a single key per table, while
	// perfect mimicry would involve writing a sentinel key for each row as well.
	descKey := sqlbase.MakeDescMetadataKey(descriptor.GetID())

	b := client.Batch{}
	descID := descriptor.GetID()
	descDesc := sqlbase.WrapDescriptor(descriptor)
	if log.V(2) {
		log.Infof("CPut %s -> %d", idKey, descID)
		log.Infof("CPut %s -> %s", descKey, descDesc)
	}
	b.CPut(idKey, descID, nil)
	b.CPut(descKey, descDesc, nil)

	p.setTestingVerifyMetadata(func(systemConfig config.SystemConfig) error {
		if err := expectDescriptorID(systemConfig, idKey, descID); err != nil {
			return err
		}
		return expectDescriptor(systemConfig, descKey, descDesc)
	})

	return true, p.txn.Run(&b)
}

// truncateTable truncates the data of a table.
// It deletes a range of data for the table, which includes the PK and all
// indexes.
func truncateTable(tableDesc *sqlbase.TableDescriptor, txn *client.Txn) error {
	tablePrefix := keys.MakeTablePrefix(uint32(tableDesc.ID))

	// Delete rows and indexes starting with the table's prefix.
	tableStartKey := roachpb.Key(tablePrefix)
	tableEndKey := tableStartKey.PrefixEnd()
	if log.V(2) {
		log.Infof("DelRange %s - %s", tableStartKey, tableEndKey)
	}
	b := client.Batch{}
	b.DelRange(tableStartKey, tableEndKey, false)
	return txn.Run(&b)
}

// deleteIndexRow adds to the batch the kv operations necessary to delete a
// table row from the given index.
func (rd *rowDeleter) deleteIndexRow(
	ctx context.Context, b *client.Batch, idx *sqlbase.IndexDescriptor, values []parser.Datum,
) error {
	if err := rd.fks.checkAll(values); err != nil {
		return err
	}
	secondaryIndexEntry, err := sqlbase.EncodeSecondaryIndex(
		rd.helper.tableDesc, idx, rd.fetchColIDtoRowIndex, values)
	if err != nil {
		return err
	}
	if log.V(2) {
		log.Infof(ctx, "Del %s", secondaryIndexEntry.Key)
	}
	b.Del(secondaryIndexEntry.Key)
	return nil
}

func convertBatchError(tableDesc *sqlbase.TableDescriptor, b *client.Batch) error {
	origPErr := b.MustPErr()
	if origPErr.Index == nil {
		return origPErr.GoError()
	}
	index := origPErr.Index.Index
	if index >= int32(len(b.Results)) {
		panic(fmt.Sprintf("index %d outside of results: %+v", index, b.Results))
	}
	result := b.Results[index]
	var alloc sqlbase.DatumAlloc
	if _, ok := origPErr.GetDetail().(*roachpb.ConditionFailedError); ok {
		for _, row := range result.Rows {
			// TODO(dan): There's too much internal knowledge of the sql table
			// encoding here (and this callsite is the only reason
			// DecodeIndexKeyPrefix is exported). Refactor this bit out.
			indexID, key, err := sqlbase.DecodeIndexKeyPrefix(&alloc, tableDesc, row.Key)
			if err != nil {
				return err
			}
			index, err := tableDesc.FindIndexByID(indexID)
			if err != nil {
				return err
			}
			valTypes, err := sqlbase.MakeKeyVals(tableDesc, index.ColumnIDs)
			if err != nil {
				return err
			}
			dirs := make([]encoding.Direction, 0, len(index.ColumnIDs))
			for _, dir := range index.ColumnDirections {
				convertedDir, err := dir.ToEncodingDirection()
				if err != nil {
					return err
				}
				dirs = append(dirs, convertedDir)
			}
			vals := make([]parser.Datum, len(valTypes))
			if _, err := sqlbase.DecodeKeyVals(&alloc, valTypes, vals, dirs, key); err != nil {
				return err
			}

			return sqlbase.NewUniquenessConstraintViolationError(index, vals)
		}
	}
	return origPErr.GoError()
}

// RenameDatabase renames the database.
// Privileges: security.RootUser user.
//   Notes: postgres requires superuser, db owner, or "CREATEDB".
//          mysql >= 5.1.23 does not allow database renames.
func (p *planner) RenameDatabase(n *parser.RenameDatabase) (planNode, error) {
	if n.Name == "" || n.NewName == "" {
		return nil, errEmptyDatabaseName
	}

	if p.session.User != security.RootUser {
		return nil, fmt.Errorf("only %s is allowed to rename databases", security.RootUser)
	}

	dbDesc, err := p.getDatabaseDesc(string(n.Name))
	if err != nil {
		return nil, err
	}
	if dbDesc == nil {
		return nil, sqlbase.NewUndefinedDatabaseError(string(n.Name))
	}

	if n.Name == n.NewName {
		// Noop.
		return &emptyNode{}, nil
	}

	// Now update the nameMetadataKey and the descriptor.
	descKey := sqlbase.MakeDescMetadataKey(dbDesc.GetID())
	dbDesc.SetName(string(n.NewName))

	if err := dbDesc.Validate(); err != nil {
		return nil, err
	}

	newKey := databaseKey{string(n.NewName)}.Key()
	oldKey := databaseKey{string(n.Name)}.Key()
	descID := dbDesc.GetID()
	descDesc := sqlbase.WrapDescriptor(dbDesc)

	b := client.Batch{}
	b.CPut(newKey, descID, nil)
	b.Put(descKey, descDesc)
	b.Del(oldKey)

	if err := p.txn.Run(&b); err != nil {
		if _, ok := err.(*roachpb.ConditionFailedError); ok {
			return nil, fmt.Errorf("the new database name %q already exists", string(n.NewName))
		}
		return nil, err
	}

	p.setTestingVerifyMetadata(func(systemConfig config.SystemConfig) error {
		if err := expectDescriptorID(systemConfig, newKey, descID); err != nil {
			return err
		}
		if err := expectDescriptor(systemConfig, descKey, descDesc); err != nil {
			return err
		}
		return expectDeleted(systemConfig, oldKey)
	})

	return &emptyNode{}, nil
}

// TestAuthentication tests authentication for the KV endpoint.
func TestAuthentication(t *testing.T) {
	defer leaktest.AfterTest(t)()
	s, _, _ := serverutils.StartServer(t, base.TestServerArgs{})
	defer s.Stopper().Stop()

	var b1 client.Batch
	b1.Put("a", "b")

	// Create a node user client and call Run() on it which lets us build our own
	// request, specifying the user.
	db1 := createTestClientForUser(t, s.Stopper(), s.ServingAddr(), security.NodeUser)
	if err := db1.Run(&b1); err != nil {
		t.Fatal(err)
	}

	var b2 client.Batch
	b2.Put("c", "d")

	// Try again, but this time with certs for a non-node user (even the root
	// user has no KV permissions).
	db2 := createTestClientForUser(t, s.Stopper(), s.ServingAddr(), security.RootUser)
	if err := db2.Run(&b2); !testutils.IsError(err, "is not allowed") {
		t.Fatal(err)
	}
}

// flush writes all dirty nodes and the tree to the transaction.
func (tc *treeContext) flush(b *client.Batch) {
	if tc.dirty {
		b.Put(keys.RangeTreeRoot, tc.tree)
	}
	for key, cachedNode := range tc.nodes {
		if cachedNode.dirty {
			if cachedNode.node == nil {
				b.Del(keys.RangeTreeNodeKey(roachpb.RKey(key)))
			} else {
				b.Put(keys.RangeTreeNodeKey(roachpb.RKey(key)), cachedNode.node)
			}
		}
	}
}

func delMeta(b *client.Batch, key roachpb.Key, desc *roachpb.RangeDescriptor) {
	b.Del(key)
}

func putMeta(b *client.Batch, key roachpb.Key, desc *roachpb.RangeDescriptor) {
	b.Put(key, desc)
}

// Execute the entire schema change in steps. startBackfillNotification is
// called before the backfill starts; it can be nil.
func (sc SchemaChanger) exec(
	startBackfillNotification func() error,
	oldNameNotInUseNotification func(),
) error {
	// Acquire lease.
	lease, err := sc.AcquireLease()
	if err != nil {
		return err
	}
	needRelease := true
	// Always try to release lease.
	defer func(l *sqlbase.TableDescriptor_SchemaChangeLease) {
		// If the schema changer deleted the descriptor, there's no longer a lease to be
		// released.
		if !needRelease {
			return
		}
		if err := sc.ReleaseLease(*l); err != nil {
			log.Warning(err)
		}
	}(&lease)

	// Increment the version and unset tableDescriptor.UpVersion.
	desc, err := sc.MaybeIncrementVersion()
	if err != nil {
		return err
	}

	if desc.GetTable().Deleted() {
		lease, err = sc.ExtendLease(lease)
		if err != nil {
			return err
		}
		// Wait for everybody to see the version with the deleted bit set. When
		// this returns, nobody has any leases on the table, nor can get new leases,
		// so the table will no longer be modified.
		if err := sc.waitToUpdateLeases(); err != nil {
			return err
		}

		// Truncate the table and delete the descriptor.
		if err := sc.truncateAndDropTable(&lease, desc.GetTable()); err != nil {
			return err
		}
		needRelease = false
		return nil
	}

	if desc.GetTable().Renamed() {
		lease, err = sc.ExtendLease(lease)
		if err != nil {
			return err
		}
		// Wait for everyone to see the version with the new name. When this
		// returns, no new transactions will be using the old name for the table, so
		// the old name can now be re-used (by CREATE).
		if err := sc.waitToUpdateLeases(); err != nil {
			return err
		}

		if oldNameNotInUseNotification != nil {
			oldNameNotInUseNotification()
		}
		// Free up the old name(s).
		err := sc.db.Txn(func(txn *client.Txn) error {
			b := client.Batch{}
			for _, renameDetails := range desc.GetTable().Renames {
				tbKey := tableKey{
					sqlbase.ID(renameDetails.OldParentID), renameDetails.OldName}.Key()
				b.Del(tbKey)
			}
			if err := txn.Run(&b); err != nil {
				return err
			}
			return nil
		})
		if err != nil {
			return err
		}

		// Clean up - clear the descriptor's state.
		_, err = sc.leaseMgr.Publish(sc.tableID, func(desc *sqlbase.TableDescriptor) error {
			desc.Renames = nil
			return nil
		}, nil)
		if err != nil {
			return err
		}
	}

	// Wait for the schema change to propagate to all nodes after this function
	// returns, so that the new schema is live everywhere. This is not needed for
	// correctness but is done to make the UI experience/tests predictable.
	defer func() {
		if err := sc.waitToUpdateLeases(); err != nil {
			log.Warning(err)
		}
	}()
//.........这里部分代码省略.........

// updateRow adds to the batch the kv operations necessary to update a table row
// with the given values.
//
// The row corresponding to oldValues is updated with the ones in updateValues.
// Note that updateValues only contains the ones that are changing.
//
// The return value is only good until the next call to UpdateRow.
func (ru *rowUpdater) updateRow(
	b *client.Batch,
	oldValues []parser.Datum,
	updateValues []parser.Datum,
) ([]parser.Datum, error) {
	if len(oldValues) != len(ru.fetchCols) {
		return nil, errors.Errorf("got %d values but expected %d", len(oldValues), len(ru.fetchCols))
	}
	if len(updateValues) != len(ru.updateCols) {
		return nil, errors.Errorf("got %d values but expected %d", len(updateValues), len(ru.updateCols))
	}

	primaryIndexKey, secondaryIndexEntries, err := ru.helper.encodeIndexes(ru.fetchColIDtoRowIndex, oldValues)
	if err != nil {
		return nil, err
	}

	// The secondary index entries returned by rowHelper.encodeIndexes are only
	// valid until the next call to encodeIndexes. We need to copy them so that
	// we can compare against the new secondary index entries.
	secondaryIndexEntries = append(ru.indexEntriesBuf[:0], secondaryIndexEntries...)
	ru.indexEntriesBuf = secondaryIndexEntries

	// Check that the new value types match the column types. This needs to
	// happen before index encoding because certain datum types (i.e. tuple)
	// cannot be used as index values.
	for i, val := range updateValues {
		if ru.marshalled[i], err = sqlbase.MarshalColumnValue(ru.updateCols[i], val); err != nil {
			return nil, err
		}
	}

	// Update the row values.
	copy(ru.newValues, oldValues)
	for i, updateCol := range ru.updateCols {
		ru.newValues[ru.fetchColIDtoRowIndex[updateCol.ID]] = updateValues[i]
	}

	rowPrimaryKeyChanged := false
	var newSecondaryIndexEntries []sqlbase.IndexEntry
	if ru.primaryKeyColChange {
		var newPrimaryIndexKey []byte
		newPrimaryIndexKey, newSecondaryIndexEntries, err =
			ru.helper.encodeIndexes(ru.fetchColIDtoRowIndex, ru.newValues)
		if err != nil {
			return nil, err
		}
		rowPrimaryKeyChanged = !bytes.Equal(primaryIndexKey, newPrimaryIndexKey)
	} else {
		newSecondaryIndexEntries, err =
			ru.helper.encodeSecondaryIndexes(ru.fetchColIDtoRowIndex, ru.newValues)
		if err != nil {
			return nil, err
		}
	}

	if rowPrimaryKeyChanged {
		if err := ru.fks.checkIdx(ru.helper.tableDesc.PrimaryIndex.ID, oldValues, ru.newValues); err != nil {
			return nil, err
		}
		for i := range newSecondaryIndexEntries {
			if !bytes.Equal(newSecondaryIndexEntries[i].Key, secondaryIndexEntries[i].Key) {
				if err := ru.fks.checkIdx(ru.helper.indexes[i].ID, oldValues, ru.newValues); err != nil {
					return nil, err
				}
			}
		}

		if err := ru.rd.deleteRow(b, oldValues); err != nil {
			return nil, err
		}
		if err := ru.ri.insertRow(b, ru.newValues, false); err != nil {
			return nil, err
		}
		return ru.newValues, nil
	}

	// Add the new values.
	// TODO(dan): This has gotten very similar to the loop in insertRow, see if
	// they can be DRY'd. Ideally, this would also work for
	// truncateAndBackfillColumnsChunk, which is currently abusing rowUdpdater.
	for i, family := range ru.helper.tableDesc.Families {
		update := false
		for _, colID := range family.ColumnIDs {
			if _, ok := ru.updateColIDtoRowIndex[colID]; ok {
				update = true
				break
			}
		}
		if !update {
			continue
		}

//.........这里部分代码省略.........

// insertPutFn is used by insertRow when conflicts should be ignored.
// logValue is used for pretty printing.
func insertPutFn(b *client.Batch, key *roachpb.Key, value *roachpb.Value) {
	if log.V(2) {
		log.InfofDepth(1, "Put %s -> %s", *key, value.PrettyPrint())
	}
	b.Put(key, value)
}

// Query returns datapoints for the named time series during the supplied time
// span.  Data is returned as a series of consecutive data points.
//
// Data is queried only at the Resolution supplied: if data for the named time
// series is not stored at the given resolution, an empty result will be
// returned.
//
// All data stored on the server is downsampled to some degree; the data points
// returned represent the average value within a sample period. Each datapoint's
// timestamp falls in the middle of the sample period it represents.
//
// If data for the named time series was collected from multiple sources, each
// returned datapoint will represent the sum of datapoints from all sources at
// the same time. The returned string slices contains a list of all sources for
// the metric which were aggregated to produce the result.
func (db *DB) Query(query tspb.Query, r Resolution, startNanos, endNanos int64) ([]tspb.TimeSeriesDatapoint, []string, error) {
	// Normalize startNanos and endNanos the nearest SampleDuration boundary.
	startNanos -= startNanos % r.SampleDuration()

	var rows []client.KeyValue
	if len(query.Sources) == 0 {
		// Based on the supplied timestamps and resolution, construct start and end
		// keys for a scan that will return every key with data relevant to the
		// query.
		startKey := MakeDataKey(query.Name, "" /* source */, r, startNanos)
		endKey := MakeDataKey(query.Name, "" /* source */, r, endNanos).PrefixEnd()
		var b client.Batch
		b.Header.ReadConsistency = roachpb.INCONSISTENT
		b.Scan(startKey, endKey, 0)

		if err := db.db.Run(&b); err != nil {
			return nil, nil, err
		}
		rows = b.Results[0].Rows
	} else {
		b := db.db.NewBatch()
		b.Header.ReadConsistency = roachpb.INCONSISTENT
		// Iterate over all key timestamps which may contain data for the given
		// sources, based on the given start/end time and the resolution.
		kd := r.KeyDuration()
		startKeyNanos := startNanos - (startNanos % kd)
		endKeyNanos := endNanos - (endNanos % kd)
		for currentTimestamp := startKeyNanos; currentTimestamp <= endKeyNanos; currentTimestamp += kd {
			for _, source := range query.Sources {
				key := MakeDataKey(query.Name, source, r, currentTimestamp)
				b.Get(key)
			}
		}
		err := db.db.Run(b)
		if err != nil {
			return nil, nil, err
		}
		for _, result := range b.Results {
			row := result.Rows[0]
			if row.Value == nil {
				continue
			}
			rows = append(rows, row)
		}
	}

	// Convert the queried source data into a set of data spans, one for each
	// source.
	sourceSpans, err := makeDataSpans(rows, startNanos)
	if err != nil {
		return nil, nil, err
	}

	// Compute a downsample function which will be used to return values from
	// each source for each sample period.
	downsampler, err := getDownsampleFunction(query.GetDownsampler())
	if err != nil {
		return nil, nil, err
	}

	// If we are returning a derivative, iteration needs to start at offset -1
	// (in order to correctly compute the rate of change at offset 0).
	var startOffset int32
	isDerivative := query.GetDerivative() != tspb.TimeSeriesQueryDerivative_NONE
	if isDerivative {
		startOffset = -1
	}

	// Create an interpolatingIterator for each dataSpan, adding each iterator
	// into a unionIterator collection. This is also where we compute a list of
	// all sources with data present in the query.
	sources := make([]string, 0, len(sourceSpans))
	iters := make(unionIterator, 0, len(sourceSpans))
	for name, span := range sourceSpans {
		sources = append(sources, name)
		iters = append(iters, span.newIterator(startOffset, downsampler))
	}

	// Choose an aggregation function to use when taking values from the
	// unionIterator.
	var valueFn func() float64
	switch query.GetSourceAggregator() {
	case tspb.TimeSeriesQueryAggregator_SUM:
		valueFn = iters.sum
	case tspb.TimeSeriesQueryAggregator_AVG:
//.........这里部分代码省略.........

// RenameTable renames the table.
// Privileges: DROP on source table, CREATE on destination database.
//   Notes: postgres requires the table owner.
//          mysql requires ALTER, DROP on the original table, and CREATE, INSERT
//          on the new table (and does not copy privileges over).
func (p *planner) RenameTable(n *parser.RenameTable) (planNode, error) {
	if err := n.NewName.NormalizeTableName(p.session.Database); err != nil {
		return nil, err
	}

	if n.NewName.Table() == "" {
		return nil, errEmptyTableName
	}

	if err := n.Name.NormalizeTableName(p.session.Database); err != nil {
		return nil, err
	}

	dbDesc, err := p.getDatabaseDesc(n.Name.Database())
	if err != nil {
		return nil, err
	}
	if dbDesc == nil {
		return nil, sqlbase.NewUndefinedDatabaseError(n.Name.Database())
	}

	tbKey := tableKey{dbDesc.ID, n.Name.Table()}.Key()

	// Check if table exists.
	gr, err := p.txn.Get(tbKey)
	if err != nil {
		return nil, err
	}
	if !gr.Exists() {
		if n.IfExists {
			// Noop.
			return &emptyNode{}, nil
		}
		// Key does not exist, but we want it to: error out.
		return nil, fmt.Errorf("table %q does not exist", n.Name.Table())
	}

	targetDbDesc, err := p.getDatabaseDesc(n.NewName.Database())
	if err != nil {
		return nil, err
	}
	if targetDbDesc == nil {
		return nil, sqlbase.NewUndefinedDatabaseError(n.NewName.Database())
	}

	if err := p.checkPrivilege(targetDbDesc, privilege.CREATE); err != nil {
		return nil, err
	}

	if n.Name.Database() == n.NewName.Database() && n.Name.Table() == n.NewName.Table() {
		// Noop.
		return &emptyNode{}, nil
	}

	tableDesc, err := p.getTableDesc(n.Name)
	if err != nil {
		return nil, err
	}
	if tableDesc == nil || tableDesc.State != sqlbase.TableDescriptor_PUBLIC {
		return nil, sqlbase.NewUndefinedTableError(n.Name.String())
	}

	if err := p.checkPrivilege(tableDesc, privilege.DROP); err != nil {
		return nil, err
	}

	tableDesc.SetName(n.NewName.Table())
	tableDesc.ParentID = targetDbDesc.ID

	descKey := sqlbase.MakeDescMetadataKey(tableDesc.GetID())
	newTbKey := tableKey{targetDbDesc.ID, n.NewName.Table()}.Key()

	if err := tableDesc.Validate(); err != nil {
		return nil, err
	}

	descID := tableDesc.GetID()
	descDesc := sqlbase.WrapDescriptor(tableDesc)

	if err := tableDesc.SetUpVersion(); err != nil {
		return nil, err
	}
	renameDetails := sqlbase.TableDescriptor_RenameInfo{
		OldParentID: uint32(dbDesc.ID),
		OldName:     n.Name.Table()}
	tableDesc.Renames = append(tableDesc.Renames, renameDetails)
	if err := p.writeTableDesc(tableDesc); err != nil {
		return nil, err
	}

	// We update the descriptor to the new name, but also leave the mapping of the
	// old name to the id, so that the name is not reused until the schema changer
	// has made sure it's not in use any more.
	b := client.Batch{}
	b.Put(descKey, descDesc)
//.........这里部分代码省略.........