Npgsqldatareader not disposing if error happens on multiple statements and not executed statement has syntax error

Steps to reproduce

Create the transaction object on connection create command and datareader by using block Create the command with multiple statements (4 statements) and make last query with syntax error Read first two result set and while reading third result pass invalid ordinal position on getfieldvalue<T> to raise error

call transaction.rollback will get the “A command is already in progress” error

Sample Code

            await using(var cmd = Connection.CreateCommand())
            {
                
               cmd.CommandText = "Correct Query 1; Correct Query 2";Correct Query 3;Query with syntax Error;";
                
                await using(var dr = await cmd.ExecuteReaderAsync())
                {
                    await dr.ReadAsync();
                    commonSettings = _CommandSettingsQuery.Read(dr);

                    await dr.NextResultAsync();
                    await dr.ReadAsync();
                    mobileSettings = _MobileSettingsQuery.Read(dr);

                    await dr.NextResultAsync();
                    await dr.ReadAsync();
                    otpFor = _OtpForQuery.Read(dr); // While reading, error will throw as passing invalid ordinal or by truncating table


                    existingUsers = new List<UserDto>();
                    if(await dr.NextResultAsync())
                    {
                        while(await dr.ReadAsync())
                        {
                            existingUsers.Add(_UserQuery.ReadUser(dr));
                        }
                    }
                }                   

            }

The issue

The Datareader should have disposed and rollback should be called without the error

If you are seeing an exception, include the full exceptions details (message and stack trace). The log shows the follows

Exception caught while disposing a reader
Npgsql.PostgresException (0x80004005): 42601: syntax error at or near "$3"
   at Npgsql.NpgsqlConnector.<ReadMessage>g__ReadMessageLong|194_0(NpgsqlConnector connector, Boolean async, DataRowLoadingMode dataRowLoadingMode, Boolean readingNotifications, Boolean isReadingPrependedMessage)
   at Npgsql.NpgsqlDataReader.NextResult(Boolean async, Boolean isConsuming, CancellationToken cancellationToken)
   at Npgsql.NpgsqlDataReader.Consume(Boolean async)
   at Npgsql.NpgsqlDataReader.Close(Boolean connectionClosing, Boolean async, Boolean isDisposing)
   at Npgsql.NpgsqlDataReader.<DisposeAsync>g__DisposeAsyncCore|67_0()
  Exception data:
    Severity: ERROR
    SqlState: 42601
    MessageText: syntax error at or near "$3"
    Position: 93
    File: scan.l
    Line: 1176
    Routine: scanner_yyerror

Further technical details

Npgsql version: 5.0.3 PostgreSQL version: 13 Operating system: Ubuntu .Net Version : .Net 5

Other details about my project setup: Asp.Net core Web Application

Is this a expected behaviour. if yes then is there anyway to rollback transaction Thank you

[vonzshik]

You actually did help me to find a few more bugs with KeepAlive, so nevermind 😃 You’re welcome.

[MohanVijayakumar]

Hi , It was my mistake and i was using was 5.0.1.1 after upgrading to 5.0.3 works as expected “Also note, that this kind of error was fixed with 5.0.2 release.” this line helped me to recheck all projects dependencies

Sorry consumed your precious time Thanks a lot