//SQLite in memory，小心，不能只写:memory:,这样每一次连接都会申请内存
    db, err := sql.Open("sqlite3", "file::memory:?mode=memory&cache=shared&loc=auto")
    if err != nil {
        fmt.Println("SQLite:", err)
    }
    defer db.Close()
    fmt.Println("SQLite start")
    //创建表//delete from BC;，SQLite字段类型比较少，bool型可以用INTEGER，字符串用TEXT
    sqlStmt := `create table BC (b_code text not null primary key, c_code text not null, code_type INTEGER, is_new INTEGER);`
    _, err = db.Exec(sqlStmt)
    if err != nil {
        fmt.Println("create table error->%q: %s\n", err, sqlStmt)
        return
    }
    //创建索引，有索引和没索引性能差别巨大，根本就不是一个量级，有兴趣的可以去掉试试
    _, err = db.Exec("CREATE INDEX inx_c_code ON BC(c_code);")
    if err != nil {
        fmt.Println("create index error->%q: %s\n", err, sqlStmt)
        return
    }
    //写入10M条记录
    start := time.Now().Unix()
    tx, err := db.Begin()
    if err != nil {
        fmt.Println("%q", err)
    }
    stmt, err := tx.Prepare("insert into BC(b_code, c_code, code_type, is_new ) values(?,?,?,?)")
    if err != nil {
        fmt.Println("insert err %q", err)
    }
    defer stmt.Close()
    var m int = 1000 * 1000
    var total int = 10 * m
    for i := 0; i < total; i++ {
        _, err = stmt.Exec(fmt.Sprintf("B%024d", i), fmt.Sprintf("C%024d", i), 0, 1)
        if err != nil {
            fmt.Println("%q", err)
        }
    }
    tx.Commit()
    insertEnd := time.Now().Unix()
    //随机检索10M次
    var count int64 = 0

    stmt, err = db.Prepare("select b_code, c_code, code_type, is_new from BC where c_code = ? ")
    if err != nil {
        fmt.Println("select err %q", err)
    }
    defer stmt.Close()
    bc := new(BCCode)
    for i := 0; i < total; i++ {

        err = stmt.QueryRow(fmt.Sprintf("C%024d", i)).Scan(&bc.B_Code, &bc.C_Code, &bc.CodeType, &bc.IsNew)
        if err != nil {
            fmt.Println("query err %q", err)
        }
        //屏幕输出会花掉好多时间啊，计算耗时的时候还是关掉比较好
        //fmt.Println("BCode=", bc.B_Code, "\tCCode=", bc.C_Code, "\tCodeType=", bc.CodeType, "\tIsNew=", bc.IsNew)
        count++
    }
    readEnd := time.Now().Unix()
    fmt.Println("insert span=", (insertEnd - start),
        "read span=", (readEnd - insertEnd),
        "avg read=", float64(readEnd-insertEnd)*1000/float64(count))