对于只读表，64位Microsoft Access dBASE驱动程序（2010）速度很慢 [英] 64-bit Microsoft Access dBASE Driver (2010) is slow for read-only tables

问题描述

在Windows 7 64位上，我正在从包含.MDX索引文件通过ODBC / ADO的大型dBase .DBF文件中读取数据。当表在读/写位置时性能良好，但当它存储在只读位置时，性能会急剧下降。
来自 进程监视器（由SysInternals）我可以告诉我在读取只读.DBF文件时没有使用.MDX索引文件，从读/写位置读取时它被正确使用。

On Windows 7 64-bit I am reading data from a large dBase .DBF file that includes an .MDX index file through ODBC/ADO. When the table is on a read/write location performance is good, but when it is stored at a read-only location performance drops radically. From the process monitor (by SysInternals) I can tell that the .MDX index file is not used when I am reading the read-only .DBF file, where it is used correcly when read from the read/write location.

在只读模式下，我可以看到驱动程序首先尝试打开具有读/写访问权限的DBF文件，从而导致"拒绝访问"。接下来，从任务管理器中可以看到整个表（大约800 MB）。在读/写模式下，这不是
的情况。

In read-only mode I can see that the driver first tries to open the DBF file with read/write access, resulting in "ACCESS DENIED". Next, the entire table (around 800 MB) is read as can be seen from the task manager. In read/write mode this is not the case.

我使用的连接字符串是：

The connection strings I used are:

DRIVER = {Microsoft Access dBASE驱动程序（* .dbf，* .ndx，* .mdx）}; DBQ = C：\somedir; DriverID = 277;

DRIVER={Microsoft Access dBASE Driver (*.dbf, *.ndx, *.mdx)}; DBQ=C:\somedir; DriverID=277;

和

Provider = Microsoft.ACE.OLEDB.12.0;数据源= C：\ somedir;扩展属性= dBase IV;'

Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\somedir;Extended Properties=dBase IV;'

通过安装"Microsoft Access数据库引擎2010可再发行组件"获得驱动程序。 （ AccessDatabaseEngine_x64.exe ）来自http://www.microsoft.com/en-us/download/details.aspx?id=13255。

The driver was obtained by installing the "Microsoft Access Database Engine 2010 Redistributable" (AccessDatabaseEngine_x64.exe) from http://www.microsoft.com/en-us/download/details.aspx?id=13255.

任何帮助对此问题表示赞赏。我无法找到与此问题相关的现有论坛帖子。

Any help on this problem is appreciated. I was unable to find existing forum posts related to this problem.

问候，

Lennert。

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您好Lennert，

Hi Lennert,

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