c# - 我怎样才能回收我的 SqliteCommand 来加速这个 Sqlite 批量插入 (iOS)？

Question

我正在使用下面的代码批量插入 30000 行(一次 1000 行)。它仍然没有那么快。在这个例子中 Improve INSERT-per-second performance of SQLite?我可以看到他们只创建了一次 SqliteCommand，然后将其重新设置为重置它并清除绑定(bind)。但是，我在 iOS/Monotouch 上找不到合适的方法。没有 Reset() 或 ClearBindings() 或任何其他类似的东西。

using ( var oConn = new SqliteConnection ( "Data Source=" + DB_NAME ) )
{
    oConn.Open (  );

    // Wrap the whole bulk insertion into one block to make it faster, otherwise one transaction per INSERT would be created.
    // Note that this is differen from "BEGIN TRANSACTION" which would increase memory usage a lot!
    SqliteCommand oCmd = new SqliteCommand ( "BEGIN", oConn );
    oCmd.ExecuteNonQuery (  );
    oCmd.Dispose (  );

    foreach ( MyObj oObj in aMyObjects )
    {
        oCmd = new SqliteCommand ( "INSERT INTO LocalObjects ( intID, intParentID, intObjectType, strName, dtModified VALUES (@intID, @intParentID, @intObjectType, @strName, @dtModified)", oConn );
        oCmd.Parameters.AddWithValue ( "@intID", oMyObj.ID );
        oCmd.Parameters.AddWithValue ( "@intParentID", oMyObj.ParentID );
        oCmd.Parameters.AddWithValue ( "@intObjectType", ( int ) oMyObj.Type );
        oCmd.Parameters.AddWithValue ( "@strName", oMyObj.Name );
        oCmd.Parameters.AddWithValue ( "@dtModified", oMyObj.Modified );
        oCmd.ExecuteNonQuery (  );
        oCmd.Dispose (  );
    }

    oCmd = new SqliteCommand ( "END", oConn );
    oCmd.ExecuteNonQuery (  );
    oCmd.Dispose (  );

    oConn.Close (  );
    oConn.Dispose (  );
}

Answer 1

尝试将您的代码更改为以下内容:

using ( var oConn = new SqliteConnection ( "Data Source=" + DB_NAME ) )
{
    oConn.Open (  );

    // Wrap the whole bulk insertion into one block to make it faster, otherwise one transaction per INSERT would be created.
    // Note that this is differen from "BEGIN TRANSACTION" which would increase memory usage a lot!
    SqliteCommand oCmd = new SqliteCommand ( "BEGIN", oConn );
    oCmd.ExecuteNonQuery (  );
    oCmd.Dispose (  );

    oCmd = new SqliteCommand ( "INSERT INTO LocalObjects ( intID, intParentID, intObjectType, strName, dtModified VALUES (@intID, @intParentID, @intObjectType, @strName, @dtModified)", oConn );

    // <do this for all of your parameters>.
    var id = oCmd.CreateParameter();
    id.ParameterName = "@intID";
    oCmd.Parameters.Add(id);
    // </do this for all of your parameters>.

    foreach ( MyObj oObj in aMyObjects )
    {
        // <do this for all of your parameters>.
        id.Value = oMyObj.ID;
        // </do this for all of your parameters>.

        oCmd.ExecuteNonQuery (  );
    }

    oCmd.Dispose();

    oCmd = new SqliteCommand ( "END", oConn );
    oCmd.ExecuteNonQuery (  );
    oCmd.Dispose (  );

    oConn.Close (  );
    oConn.Dispose (  );
}

基本上，在每个循环中，现在您只需更改参数的值，而不是构建一个全新的查询。但是，我不确定，您的表现是否真的会从中受益。您需要尝试一下。