I have a console application that populates a SQLite database. When the application runs by itself, I don't get any errors. If I run multiple instances of the application, where each application is in its own folder and each populates its own database I'll occasionally get the following exception:
System.Data.SQLite.SQLiteException (0x80004005): Attempt to write a read-only database
attempt to write a readonly database
at System.Data.SQLite.SQLite3.Reset(SQLiteStatement stmt)
at System.Data.SQLite.SQLite3.Step(SQLiteStatement stmt)
at System.Data.SQLite.SQLiteDataReader.NextResult()
at System.Data.SQLite.SQLiteDataReader..ctor(SQLiteCommand cmd, CommandBehavior behave)
at System.Data.SQLite.SQLiteCommand.ExecuteReader(CommandBehavior behavior)
at System.Data.SQLite.SQLiteCommand.ExecuteNonQuery()
I know the DB isn't read-only because it has already written data to that database. Also, the app continues on and will continue populating data to that database. I haven't reproduced the error when only a single instance of the application is running.
I've tried using the pragma to have both the journal and temp_store in memory instead of to a file in case there could be some contention across applications there, but I still get the error. I do always get the error in the same method, which is the first time an insert would happen for the connection. To give a general idea of what the application does, it loops over cases, gathers info about those cases (not from SQLite), then writes results to the SQLite database.
I don't know what else to try.
*edit I am also using the PRAGMA journal_mode=MEMORY. When inserting data into the SQLite database, I first run a BEGIN statement, then a bunch of inserts before the END statement. The error occurs on the first insert.
