Unable to connect to database-request failed or server failed to respond in time.

Error: the following error occurs during database connection.

1. Go to the database configuration file to start the service.

2. An error is prompted during service startup:

3. Find a solution:

Solution:

Enable the "via protocol" and disable the "via protocol" to solve the problem. "Via protocol" Deactivation method: start-> Program-> Microsoft SQL Server 2005-> Configuration tool-> SQL Server Configuration Manager-> open and find "SQL Server 2005 network configuration"-> protocol of MSSQLServer attribute on the right in the properties box, disable the "via protocol!

After being disabled, the service can be started.

The database can also be connected successfully.

Reflection: Why does enabling the via protocol cause the server to fail to start?

First, let's look at what is.

Via -- Virtual Interface Architecture, Virtual Interface System, any device can be considered as a virtual device, is the abstract of implementation, originally to adapt to different hardware manufacturers, adapt to different networks, or Java virtual machine, cross-platform, etc. The results are too idealistic, and the implementation of large targets is complicated and difficult. the virtual interface adapter (VIA) protocol is used together with the via hardware.

The reason why the server cannot be started is as follows.

If two or more Microsoft SQL Server instances are installed on the same computer, the via connection may be ambiguous. When the via protocol is enabled, you will try to use the TCP/IP Settings and listen on the port 0: 1433. For Via drivers that do not allow port configuration, both SQL Server instances listen on the same port. The incoming client connection may be a connection to the correct server instance or an incorrect server instance, or the connection may be rejected because the port is being used.

My computer has installed three Microsoft SQL Server instances, which causes problems.

At this point, the problem is solved. At the same time, Microsoft officially recommends that the via Protocol not be used. This function will be deleted in later versions of Microsoft SQL Server. Avoid using this function in new development work, and start to modify the application that is currently using this function.