SQLite.SQLiteException: database disk image is malformed in xamarin.forms application

Question

I have created a xamarin.forms application and ship a sqlite database with the application, im getting the following error:

database disk image is malformed.

This is the stacktrace:

SQLite3.Prepare2 (SQLitePCL.sqlite3 db, System.String query)
SQLiteCommand.Prepare ()
SQLiteCommand+<ExecuteDeferredQuery>d__12`1[T].MoveNext ()
List`1[T].AddEnumerable (System.Collections.Generic.IEnumerable`1[T] enumerable)
System.Collections.Generic.List`1[T]..ctor (System.Collections.Generic.IEnumerable`1[T] collection) [0x00062] in <d4a23bbd2f544c30a48c44dd622ce09f>:0
Enumerable.ToList[TSource] (System.Collections.Generic.IEnumerable`1[T] source)
SQLiteCommand.ExecuteQuery[T] ()
SQLiteConnection.Query[T] (System.String query, System.Object[] args)
SQLiteAsyncConnection+<>c__DisplayClass28_0`1[T].<QueryAsync>b__0 ()
Task`1[TResult].InnerInvoke ()
Task.Execute ()
MyApp+<LoadDocFromDB>d__18.MoveNext ()
VolumeView+<VolumesListView_ItemSelected>d__13.MoveNext ()
AsyncMethodBuilderCore+<>c.<ThrowAsync>b__6_0 (System.Object state)
SyncContext+<>c__DisplayClass2_0.<Post>b__0 ()
Thread+RunnableImplementor.Run ()
IRunnableInvoker.n_Run (System.IntPtr jnienv, System.IntPtr native__this)
(wrapper dynamic-method) System.Object.17(intptr,intptr)

this is happening on both Xamarin iOS and Xamarin Android.

the xamarin forms versions i use are: 4.3.0.947036

i use the following sqlite packages: SQLiteNetExtensions version 2.1.0 SQLiteNetExtensions.Async version 2.1.0

this is the following code that is crashing:

public static async Task LoadDocFromDB(string volume, int chapterNr)
{
    if(dbPath == null)
    {
        dbPath = await DependencyService.Get<IDatabaseAccess>().DatabasePathAsync(false,"Data");
    }
    var connection = new SQLiteAsyncConnection(dbPath, SQLiteOpenFlags.FullMutex | SQLiteOpenFlags.ReadWrite);
    IRepository<Doc> repository = new DocRepository<Doc>(connection);
    try
    {
        var docMetadata = await repository.QueryAsync($"SELECT * FROM [Docs] WHERE [volume] == '{volume}' AND [chapterNr] == '{chapterNr}'");
        LoadedDoc = await repository.GetWithChildrenAsync(docMetadata.First().chapterID);
        await repository.DisposeDbConnectionAsync();
    }
    catch (Exception ex)
    {
        throw;
    }
    await Task.FromResult(0);
}

this is the DisposeDbConnectionAsync() method implementation:

public async Task DisposeDbConnectionAsync()
        {
            using (await _mutex.LockAsync()) //from the Nito.AsyncEx library
            {
                if (dbConnection != null)
                {
                    dbConnection.GetConnection().Close();
                    GC.Collect();
                    GC.WaitForPendingFinalizers();
                    dbConnection.GetConnection().Dispose();
                    SQLite.SQLiteAsyncConnection.ResetPool();
                    dbConnection = null;
                }
            }
        }

This seem to happen sometimes, any clue what might be causing this?

I have also run a Pragma integrity check on the database and its was ok, no issues.

thanks for all the help!

Answer 1

I had the same problem, after a lot research, the problem was related with the SQL file saving checks. I recommend you do the following checks:

• Always check if already exists a SQL file before overwrite;
• Always delete the SQL file before save new one with the same name;

Answer 2

I have not found the solution for this exception, however i solved it in my application by catching the exception and then in the catch clause removing the corrupt database from the specialfolders, and copy in a new copy of the database to the special folders, this solved the issue and the app stopped crashing at least.

The exception might have been caused by some corruption during an initial copy of the database. Hope this helps anyone facing the same issue!