func (s *server) GetDB(ix int) (DB, bool) {
	if ix < 0 || ix >= maxDBs {
		return nil, false
	}
	db := s.dbs[ix]
	if db == nil {
		db = NewDB(ix)
		s.dbs[ix] = db
	}
	return db, true
}
GetDB returns the database identified by its index.
package srv
import (
	"sync"
	"time"
)
type Server interface {
	RWLocker
	FlushAll()
	GetDB(int) (DB, bool)
	Time() (int64, int64)
}
const maxDBs = 16  
var _ Server = (*server)(nil)
var DefaultServer Server
type server struct {
	sync.RWMutex
	dbs []DB
}
func init() {
	DefaultServer = &server{
		dbs: make([]DB, maxDBs),
	}
}
func (s *server) FlushAll() {
	s.dbs = make([]DB, maxDBs)
}