// exec executes the request. Any error encountered is returned; it is
// the caller's responsibility to update the response.
func (e *Executor) execStmts(sql string, planMaker *planner) driver.Response {
var resp driver.Response
stmts, err := planMaker.parser.Parse(sql, parser.Syntax(planMaker.session.Syntax))
if err != nil {
// A parse error occurred: we can't determine if there were multiple
// statements or only one, so just pretend there was one.
resp.Results = append(resp.Results, makeResultFromError(planMaker, err))
return resp
}
for _, stmt := range stmts {
result, err := e.execStmt(stmt, planMaker)
if err != nil {
result = makeResultFromError(planMaker, err)
}
resp.Results = append(resp.Results, result)
// Release the leases once a transaction is complete.
if planMaker.txn == nil {
planMaker.releaseLeases(e.db)
// The previous transaction finished executing some schema changes. Wait for
// the schema changes to propagate to all nodes, so that once the executor
// returns the new schema are live everywhere. This is not needed for
// correctness but is done to make the UI experience/tests predictable.
if err := e.waitForCompletedSchemaChangesToPropagate(planMaker); err != nil {
log.Warning(err)
}
}
}
return resp
}
// exec executes the request. Any error encountered is returned; it is
// the caller's responsibility to update the response.
func (s *Server) exec(req driver.Request) (driver.Response, error) {
var resp driver.Response
// Pick up current session state.
planner := planner{db: s.db}
if req.Session != nil {
// TODO(tschottdorf) will have to validate the Session information (for
// instance, whether access to the stored database is permitted).
if err := gogoproto.Unmarshal(req.Session, &planner.session); err != nil {
return resp, err
}
}
stmts, err := parser.Parse(req.Sql)
if err != nil {
return resp, err
}
for _, stmt := range stmts {
// Bind all the placeholder variables in the stmt to actual values.
if err := parser.FillArgs(stmt, parameters(req.Params)); err != nil {
return resp, err
}
var plan planNode
if plan, err = planner.makePlan(stmt); err != nil {
return resp, err
}
result := driver.Result{
Columns: plan.Columns(),
}
for plan.Next() {
values := plan.Values()
row := driver.Result_Row{}
row.Values = make([]driver.Datum, 0, len(values))
for _, val := range values {
switch vt := val.(type) {
case parser.DBool:
row.Values = append(row.Values, driver.Datum{BoolVal: (*bool)(&vt)})
case parser.DInt:
row.Values = append(row.Values, driver.Datum{IntVal: (*int64)(&vt)})
case parser.DFloat:
row.Values = append(row.Values, driver.Datum{FloatVal: (*float64)(&vt)})
case parser.DString:
row.Values = append(row.Values, driver.Datum{StringVal: (*string)(&vt)})
case parser.DNull:
row.Values = append(row.Values, driver.Datum{})
default:
return resp, util.Errorf("unsupported datum: %T", val)
}
}
result.Rows = append(result.Rows, row)
}
resp.Results = append(resp.Results, result)
}
// Update session state.
resp.Session, err = gogoproto.Marshal(&planner.session)
return resp, err
}
// exec executes the request. Any error encountered is returned; it is
// the caller's responsibility to update the response.
func (e *Executor) execStmts(sql string, planMaker *planner) driver.Response {
var resp driver.Response
stmts, err := planMaker.parser.Parse(sql, parser.Syntax(planMaker.session.Syntax))
if err != nil {
// A parse error occurred: we can't determine if there were multiple
// statements or only one, so just pretend there was one.
resp.Results = append(resp.Results, makeResultFromError(planMaker, err))
return resp
}
for _, stmt := range stmts {
result, err := e.execStmt(stmt, planMaker)
if err != nil {
result = makeResultFromError(planMaker, err)
}
// Release the leases once a transaction is complete.
if planMaker.txn == nil {
planMaker.releaseLeases(e.db)
// Execute any schema changes that were scheduled.
if len(planMaker.schemaChangers) > 0 &&
// Disable execution in some tests.
!disableSyncSchemaChangeExec {
retryOpts := retry.Options{
InitialBackoff: 20 * time.Millisecond,
MaxBackoff: 200 * time.Millisecond,
Multiplier: 2,
}
for _, sc := range planMaker.schemaChangers {
sc.db = e.db
for r := retry.Start(retryOpts); r.Next(); {
if done, err := sc.IsDone(); err != nil {
log.Warning(err)
break
} else if done {
break
}
if err := sc.exec(); err != nil {
if err == errExistingSchemaChangeLease {
// Try again.
continue
}
// All other errors can be reported.
result = makeResultFromError(planMaker, err)
}
break
}
}
}
}
resp.Results = append(resp.Results, result)
}
return resp
}
// ShowTables returns all the tables.
func (s *Server) ShowTables(session *Session, p *parser.ShowTables, args []driver.Datum, resp *driver.Response) error {
if p.Name == nil {
if session.Database == "" {
return errNoDatabase
}
p.Name = append(p.Name, session.Database)
}
dbID, err := s.lookupDatabase(p.Name.String())
if err != nil {
return err
}
prefix := keys.MakeNameMetadataKey(dbID, "")
sr, err := s.db.Scan(prefix, prefix.PrefixEnd(), 0)
if err != nil {
return err
}
var rows []driver.Result_Row
for _, row := range sr {
name := string(bytes.TrimPrefix(row.Key, prefix))
rows = append(rows, driver.Result_Row{
Values: []driver.Datum{
{StringVal: &name},
},
})
}
resp.Results = []driver.Result{
{
Columns: []string{"tables"},
Rows: rows,
},
}
return nil
}
// ShowIndex returns all the indexes for a table.
func (s *Server) ShowIndex(session *Session, p *parser.ShowIndex, args []driver.Datum, resp *driver.Response) error {
desc, err := s.getTableDesc(session.Database, p.Table)
if err != nil {
return err
}
// TODO(pmattis): This output doesn't match up with MySQL. Should it?
var rows []driver.Result_Row
name := p.Table.Table()
for i, index := range desc.Indexes {
for j, col := range index.ColumnNames {
seq := int64(j + 1)
c := col
rows = append(rows, driver.Result_Row{
Values: []driver.Datum{
{StringVal: &name},
{StringVal: &desc.Indexes[i].Name},
{BoolVal: &desc.Indexes[i].Unique},
{IntVal: &seq},
{StringVal: &c},
},
})
}
}
resp.Results = []driver.Result{
{
// TODO(pmattis): This output doesn't match up with MySQL. Should it?
Columns: []string{"Table", "Name", "Unique", "Seq", "Column"},
Rows: rows,
},
}
return nil
}
// ShowColumns of a table
func (s *Server) ShowColumns(session *Session, p *parser.ShowColumns, args []driver.Datum, resp *driver.Response) error {
desc, err := s.getTableDesc(session.Database, p.Table)
if err != nil {
return err
}
var rows []driver.Result_Row
for i, col := range desc.Columns {
t := col.Type.SQLString()
rows = append(rows, driver.Result_Row{
Values: []driver.Datum{
{StringVal: &desc.Columns[i].Name},
{StringVal: &t},
{BoolVal: &desc.Columns[i].Nullable},
},
})
}
// TODO(pmattis): This output doesn't match up with MySQL. Should it?
resp.Results = []driver.Result{
{
Columns: []string{"Field", "Type", "Null"},
Rows: rows,
},
}
return nil
}
// exec executes the request. Any error encountered is returned; it is
// the caller's responsibility to update the response.
func (s server) execStmts(sql string, params parameters, planMaker *planner) driver.Response {
var resp driver.Response
stmts, err := parser.Parse(sql, parser.Syntax(planMaker.session.Syntax))
if err != nil {
// A parse error occured: we can't determine if there were multiple
// statements or only one, so just pretend there was one.
resp.Results = append(resp.Results, rollbackTxnAndReturnResultWithError(planMaker, err))
return resp
}
for _, stmt := range stmts {
result, err := s.execStmt(stmt, params, planMaker)
if err != nil {
result = rollbackTxnAndReturnResultWithError(planMaker, err)
}
resp.Results = append(resp.Results, result)
}
return resp
}
// exec executes the request. Any error encountered is returned; it is
// the caller's responsibility to update the response.
func (e *Executor) execStmts(sql string, params parameters, planMaker *planner) driver.Response {
var resp driver.Response
stmts, err := parser.Parse(sql, parser.Syntax(planMaker.session.Syntax))
if err != nil {
// A parse error occurred: we can't determine if there were multiple
// statements or only one, so just pretend there was one.
resp.Results = append(resp.Results, makeResultFromError(planMaker, err))
return resp
}
for _, stmt := range stmts {
result, err := e.execStmt(stmt, params, planMaker)
if err != nil {
result = makeResultFromError(planMaker, err)
}
resp.Results = append(resp.Results, result)
// TODO(pmattis): Is this the correct time to be releasing leases acquired
// during execution of the statement?
//
// TODO(pmattis): Need to record the leases used by a transaction within
// the transaction state and restore it when the transaction is restored.
planMaker.releaseLeases(e.db)
}
return resp
}
// ShowDatabases returns all the databases.
func (s *Server) ShowDatabases(session *Session, p *parser.ShowDatabases, args []driver.Datum, resp *driver.Response) error {
prefix := keys.MakeNameMetadataKey(structured.RootNamespaceID, "")
sr, err := s.db.Scan(prefix, prefix.PrefixEnd(), 0)
if err != nil {
return err
}
var rows []driver.Result_Row
for _, row := range sr {
name := string(bytes.TrimPrefix(row.Key, prefix))
rows = append(rows, driver.Result_Row{
Values: []driver.Datum{
{StringVal: &name},
},
})
}
resp.Results = []driver.Result{
{
Columns: []string{"Database"},
Rows: rows,
},
}
return nil
}
// Select selects rows from a single table.
func (s *Server) Select(session *Session, p *parser.Select, args []driver.Datum, resp *driver.Response) error {
if len(p.Exprs) != 1 {
return fmt.Errorf("TODO(pmattis): unsupported select exprs: %s", p.Exprs)
}
if _, ok := p.Exprs[0].(*parser.StarExpr); !ok {
return fmt.Errorf("TODO(pmattis): unsupported select expr: %s", p.Exprs)
}
if len(p.From) != 1 {
return fmt.Errorf("TODO(pmattis): unsupported from: %s", p.From)
}
var desc *structured.TableDescriptor
{
ate, ok := p.From[0].(*parser.AliasedTableExpr)
if !ok {
return fmt.Errorf("TODO(pmattis): unsupported from: %s", p.From)
}
table, ok := ate.Expr.(parser.QualifiedName)
if !ok {
return fmt.Errorf("TODO(pmattis): unsupported from: %s", p.From)
}
var err error
desc, err = s.getTableDesc(session.Database, table)
if err != nil {
return err
}
}
// Retrieve all of the keys that start with our index key prefix.
startKey := proto.Key(encodeIndexKeyPrefix(desc.ID, desc.Indexes[0].ID))
endKey := startKey.PrefixEnd()
sr, err := s.db.Scan(startKey, endKey, 0)
if err != nil {
return err
}
// All of the columns for a particular row will be grouped together. We loop
// over the returned key/value pairs and decode the key to extract the
// columns encoded within the key and the column ID. We use the column ID to
// lookup the column and decode the value. All of these values go into a map
// keyed by column name. When the index key changes we output a row
// containing the current values.
//
// The TODOs here are too numerous to list. This is only performing a full
// table scan using the primary key.
var rows []driver.Result_Row
var primaryKey []byte
vals := valMap{}
l := len(sr)
// Iterate through the scan result set. We decide at the beginning of each
// new row whether the previous row is to be output. To deal with the very
// last one, the loop below goes an extra iteration (i==l).
for i := 0; ; i++ {
var kv client.KeyValue
if i < l {
kv = sr[i]
}
if primaryKey != nil && (i == l || !bytes.HasPrefix(kv.Key, primaryKey)) {
// The current key belongs to a new row. Decide whether the last
// row is to be output.
if output, err := shouldOutputRow(p.Where, vals); err != nil {
return err
} else if output {
rows = append(rows, outputRow(desc.Columns, vals))
}
vals = valMap{}
}
if i >= l {
break
}
remaining, err := decodeIndexKey(desc, desc.Indexes[0], vals, kv.Key)
if err != nil {
return err
}
primaryKey = []byte(kv.Key[:len(kv.Key)-len(remaining)])
_, colID := encoding.DecodeUvarint(remaining)
if err != nil {
return err
}
col, err := desc.FindColumnByID(uint32(colID))
if err != nil {
return err
}
vals[col.Name] = unmarshalValue(*col, kv)
if log.V(2) {
log.Infof("Scan %q -> %v", kv.Key, vals[col.Name])
}
}
resp.Results = []driver.Result{
{
Columns: make([]string, len(desc.Columns)),
Rows: rows,
},
}
for i, col := range desc.Columns {
resp.Results[0].Columns[i] = col.Name
}
return nil
}