System.data.sqlite - Activating WAL Journal Mode

Question

I am using the System.data.sqlite.dll in my vb.net program. And for the life of me I can't figure out the code to activate WAL mode.

Do I activate this command right after I Create the DB or with every new SQLiteConnection.

And if so what code would need to be used right now im using something like:

cnn As New SQLiteConnection(String.Format("Data Source={0}\{1};PRAGMA jounal_mode=WAL;", Application.StartupPath, DBName))

is this how that PRAGMA command should be used?

Answer 1

You can always use the SQLiteConnectionStringBuilder class to do the job for you:

    SQLiteConnectionStringBuilder connBuilder = new SQLiteConnectionStringBuilder();
    connBuilder.DataSource = filePath;
    connBuilder.Version = 3;
    //Set page size to NTFS cluster size = 4096 bytes
    connBuilder.PageSize = 4096;
    connBuilder.CacheSize = 10000;
    connBuilder.JournalMode = SQLiteJournalModeEnum.Wal;
    connBuilder.Pooling = true;
    connBuilder.LegacyFormat = false;
    connBuilder.DefaultTimeout = 500;
    connBuilder.Password = "yourpass";


    using(SQLiteConnection conn = new SQLiteConnection(connBuilder.ToString()))
    {
    //Database stuff
    }

Answer 2

This is a sample connection string from my project (App.config):

  <connectionStrings>
    <add name="SQLiteDb" providerName="System.Data.SQLite" connectionString="Data Source=data.sqlite;Version=3;Pooling=True;Synchronous=Off;journal mode=Memory"/>
  </connectionStrings>

Instead of journal mode=Memory you can specify journal mode=WAL.

If you don't specify journal mode in connection string, you can switch it manually by executing PRAGMA jounal_mode=WAL query to database.

Answer 3

You need to execute the pragma as a command nonquery.

Using cmd As SQLiteCommand = cnn.CreateCommand()
   cmd.CommandText = "PRAGMA journal_mode=WAL"
   cmd.ExecuteNonQuery()
End Using

As long as you keep your connection open, setting this once will be enough.