NpgsqlCopyIn fails by timeout ("CommandTimeout" setting ignored)

StackOverflow https://stackoverflow.com/questions/22762243

Question

I have a quite large dataset (900K records, 140Mb disk space) stored in CSV file in a client app (.NET 4.0). I need to load this data to Postgres 9 db the fastest way. I use Npgsql "NpgsqlCopyIn" technique (Npgsql library version=2.1.0).

For a probe load (138K) insertion works fine - it takes about 7 secons. But for the whole batch (900K), the code throws timeout exception:

  "ERROR: 57014: canceling statement due to statement timeout"

The stack trace is:

Npgsql.NpgsqlState.d_9.MoveNext() at Npgsql.NpgsqlState.ProcessAndDiscardBackendResponses(NpgsqlConnector context) at Npgsql.NpgsqlCopyInState.SendCopyDone(NpgsqlConnector context) at Npgsql.NpgsqlCopyInState.StartCopy(NpgsqlConnector context, NpgsqlCopyFormat copyFormat) at Npgsql.NpgsqlState.d_9.MoveNext() at Npgsql.NpgsqlState.ProcessAndDiscardBackendResponses(NpgsqlConnector context) at Npgsql.NpgsqlConnector.ProcessAndDiscardBackendResponses() at Npgsql.NpgsqlCommand.ExecuteBlind() at Npgsql.NpgsqlCopyIn.Start()

I tried setting CommandTimeout to kilo values(>7200), zero; tried same values for connection "Timeout" parameter. Also I was trying to set "CommandTimeout" via connection string, but still with no result - "ERROR 57014" comes out again and again.

Please, help to load the batch correctly!

Here is the code I use:

private static void pgBulkCopy(string connection_string, FileInfo fiDataFile)
{
    using (Npgsql.NpgsqlConnection con = new Npgsql.NpgsqlConnection(connection_string))
    {
        con.Open();

        FileStream ifs = new FileStream(fiDataFile.FullName, FileMode.Open, FileAccess.Read);
        string queryString = "COPY schm.Addresses(FullAddress,lat,lon) FROM STDIN;";
        NpgsqlCommand cmd = new NpgsqlCommand(queryString, con);
        cmd.CommandTimeout = 7200; //7200sec, 120 min, 2 hours

        NpgsqlCopyIn copyIn = new NpgsqlCopyIn(cmd, con, ifs);

        try{
            copyIn.Start();    
            copyIn.End();
        }catch(Exception ex)
        {
            Console.WriteLine("[DB] pgBulkCopy error: " + ex.Message );
        }
        finally
        {
            con.Close();
        }
    }
}
Was it helpful?

Solution

Npgsql has a bug regarding command timeout and NpgsqlCopyIn handling.

You may test our current master where we had a lot of fixes about command timeout handling.

You can download a copy of the project in our GitHub page: https://github.com/npgsql/Npgsql/archive/master.zip

Please, give it a try and let us know if it works for you.

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