I have an ASP.Net 4.0 website which uses SQL Server CE and EF code-first for its data store. When 2 or more users are on the site I intermittently get the following exception about every 5th or 6th time.
There is a file sharing violation. A different process might be using
the file. [D:\directory…\file.sdf].
Throughout the code I create, use, and promptly dispose of the DbContext each time one is needed. Even though it is the default, I have added File Mode = Read Write to the connection string.
Any ideas what I might be doing wrong.
I think I figure out what happened. I found a link (unfortunately I do not recall where), that mentions that Go Daddy shared hosting uses a load balancer and multiple servers to serve the site. Even though the database file shows up on a drive mounted with a drive letter, clearly it must be located on a file server that all the webservers share.
Using SQL CE by multiple clients over a network is a nonsupported configuration. When I upgraded from SQL Compact to a SQL Server Instance provided by Go Daddy, the problem (and another data consistency problem I did not mention above) went away.
I am a little surprised that I did not find this problem when I googled it. Microsoft is pmarketing SQL Compact as a good back end for small website. If I am correct, this seems to be a significant liability in that regard.