I have a windows service that uploads data to a database and a MVC-app that utilises said service. The way it works today is something like this:
Upload(someStuff);
WriteLog("Uploaded someStuff");
ReadData(someTable);
WriteLog("Reading someTable-data");
Drop(oldValues);
WriteLog("Dropping old values");
private void Upload(var someStuff)
{
using(var conn = new connection(connectionstring))
{
//performQuery
}
}
private void WriteLog(string message)
{
using(var conn = etc..)
//Insert into log-table
}
private string ReadData(var table)
{
using etc..
//Query
}
///You get the gist.
The client can then see the current status of the upload through a query to the log-table.
I want to be able to perform a rollback if something fails. My first thought was to use a BeginTransaction()
and then lastly a transaction.Commit()
, but that would make my status-message behave bad. It would just go from "starting upload" and then fastforward to the last step where it would wait for a long time before "Done".
I want the user to be able to see if the process is stuck on some specific step, but I still want to be able to perform a full rollback if something unexpected happens.
How do I achieve this?
Edit: I don't seem to have been clear in my question. If I do a separate connection for the logging, that would indeed work-ish. The problem is that the actual code will execute super-fast so the statusmessages would pass so fast that the user wouldn't even be able to see them before the final "committing"-message that would take 99% of the upload-time.
Design your table so that it has a (P)ending, (A)ctive (D)eleted flag - then to perform an update, new records are created called 'pending' Status P - your very final stage is to change the current Active to Deleted, and the Pending to Active (you could do that in a transaction). At your leisure, you can then delete the Status D (deleted) records at some time.
In the event of an error, the 'pending' record could become Deleted