db,err  := ConnectDatabase(ctx)
                         if err != nil {
                              return err
                         }
			// for i := 0; i < 10000; i++ {
			// 	s := fmt.Sprintf("create table test_more.table_%04v(id bigint,col1 varchar(10))",i)
			// 	db.Exec(s)
			// 	s = fmt.Sprintf("insert into test_more.table_%04v values (1,'col1')",i)
			// 	db.Exec(s)
			// }
			doSelect := func(i int64) {
				s := fmt.Sprintf("select id, col1 from test_more.table_%04v ",i)
				rows, err := db.Query(s)
				if err != nil {
					if strings.Contains(err.Error(),"undefined name") {
						return
					}
					panic(err)
				}
				// defer rows.Close()
				for rows.Next() {
					var (
						v  string
						id int
					)
					if err := rows.Scan(&id, &v); err != nil {
						panic(err)
					}
				}
				rows.Close()
				// fmt.Println(i)
			}
			taskChan := make(chan int64, 20)
			doTableDataTaskWorker := func() {
				for {
					select {
					case i, ok := <-taskChan:
						if !ok {
							return
						}
						doSelect(i)
					}
				}
			}
			wg := sync.WaitGroup{}
			parallel := 4
			wg.Add(parallel)
			for i := 0; i < parallel; i++ {
				go func(workNum int) {
					defer wg.Done()
					doTableDataTaskWorker()
				}(i)
			}
			go func() {
				for i := 0; i < 10000; i++ {
					taskChan <- int64(i)
				}
				close(taskChan)
			}()
			wg.Wait()
			db.Close()