Question

Needing to store about 20,000 rows of information locally in SQLite Database. There are only two columns containing short text strings, so the actual amount of data is small, but I am struggling to get the rows inserted in under 3-5 minutes on the device. I’ve tried just straight up looping through the dataset and calling a simple WritableDatabase.Insert, but that took a long time. So I did some research and was led to the InsertHelper class where the author sites processing rows at about 900 rows/second (which should put me at 20-30 seconds). I still can’t get the data to process any faster than 3-5 minutes. What am I missing? Does performance vary by device? Using ZTE Optik Android 3.2.1.

public class SqLiteHelper : SQLiteOpenHelper
{
    private const string DATABASE_NAME = "NAME";
    private const int DATABASE_VERSION = 1;
    private readonly Context _context;

    public SqLiteHelper(Context context)
        : base(context, DATABASE_NAME, null, DATABASE_VERSION)
    {
        _context = context;
    }

    public override void OnCreate(SQLiteDatabase db)
    {
        try
        {
            db.ExecSQL("Create Table Inventory (ItemNumber Text Primary Key Not Null, ItemDescription Text);");
        }
        catch (SQLiteException ex)
        {
            Toast.MakeText(_context, ex.Message, ToastLength.Long).Show();
        }
    }

    public override void OnUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)
    {
    }
}

class InventoryRepository : AsyncTask
{
    private SqLiteHelper Helper { get; set; }
    private Context Context { get; set; }

    public InventoryRepository(SqLiteHelper helper, Context context)
    {
        Helper = helper;
        Context = context;
    }

    protected override Java.Lang.Object DoInBackground(params Java.Lang.Object[] @params)
    {
       WS ws = new WS();
       DataTable parts = ws.GetInventory();  //Web service getting inventory items from Server

        Helper.WritableDatabase.Delete("Inventory", null, null);

        DatabaseUtils.InsertHelper ih = new DatabaseUtils.InsertHelper(Helper.WritableDatabase, "Inventory");

        Helper.WritableDatabase.SetLockingEnabled(false);

        int partColumn = ih.GetColumnIndex("ItemNumber");
        int partDescColumn = ih.GetColumnIndex("ItemDescription");

        Helper.WritableDatabase.BeginTransaction();

        try
        {

            foreach (DataRow part in parts.Rows)
            {
                try
                {
                    ih.PrepareForInsert();

                    ih.Bind(partColumn, part[0].ToString().Replace("'", "''"));
                    ih.Bind(partDescColumn, part[1].ToString().Replace("'", "''"));

                    ih.Execute();
                }
                catch (SQLiteException ex)
                {
                    if (ex.Message.Contains("constraint"))
                        continue;
                    throw;
                }
                catch (NullReferenceException e)
                {
                    continue;
                }
            }
            Helper.WritableDatabase.SetTransactionSuccessful();

        }
        finally
        {
            Helper.WritableDatabase.EndTransaction();
            Helper.WritableDatabase.SetLockingEnabled(true);
            ih.Close();
        }

        return "Done";
    }

    protected override void OnPostExecute(Java.Lang.Object result)
    {
        PreferenceManager.GetDefaultSharedPreferences(Context).Edit().PutString("LastInventoryUpdate", DateTime.Today.ToShortDateString()).Commit();
        Intent intent = new Intent(Context, typeof(Login));
        intent.AddFlags(ActivityFlags.NewTask);
        Context.StartActivity(intent);
    }
}

Answer 1

Wrap the entire insert loop in a transaction. This will speed things up by an order of magnitude.

db.beginTransaction();
try {
    // your insertion loop goes here
    db.setTransactionSuccessful();
} finally {
    db.endTransaction();
}