UPDATE: 2013/11/19 - CR #751207 has now been fixed in 12.0.1.4015 and 16.0.0.1734 and higher

Hi Simon,

Yes, I can also reproduce this issue - thanks for the report. When posting to the forum in the future to report an error though, please also post a short code sample to illustrate what you're trying specifically to see the error - this will help us reproduce your issue more quickly.

Here is what I tried:

SQL:

create procedure p1 ( @in_val long varchar)
begin
  select 1;
end;

C#:

SAConnection conn = new SAConnection("uid=dba;pwd=sql;eng=demo");
conn.Open();

SACommand comm = new SACommand();
comm.Connection = conn;
comm.CommandType = System.Data.CommandType.StoredProcedure;
comm.CommandText = "p1";

SACommandBuilder.DeriveParameters(comm);
foreach (SAParameter saparm in comm.Parameters){
  Console.Out.WriteLine("Parameter: " + saparm.ParameterName + ", size: " + saparm.Size + "\n");
}

You can note that the procedure parameters are actually described by the system table SYS.SYSPROCPARMS in the SQL Anywhere database (which is where the ADO.NET provider looks for these values).

A 'long varchar' parameter (and other LOBs) is described as 32767 bytes there also, however this usage is really intended for allocating the largest buffer size that can be used in an ODBC/ESQL environment (e.g. is the return value in SQLDescribeParam and corresponds to a LOB's transfer octet length), so the system value is not really 'incorrect' from that usage standpoint.

However, I would agree that this seems to be a bug for ADO.NET in the provider environment, and that the value should really be '2147483647' (the actual maximum length):

From: SqlParameter.Size Property

For variable-length data types, Size describes the maximum amount of data to transmit to the server.

As a side-note, in Microsoft SQL Server via SqlCommandBuilder.DeriveParameters with similar code as above, this field is described back as length -1 as you had originally indicated:

CREATE PROCEDURE p1
@p1 varbinary(max)
AS
BEGIN
SET NOCOUNT ON
    SELECT 1
END
GO

Results:

Parameter: @RETURN_VALUE, size: 0
Parameter: @p1, size: -1

I have now opened CR #751207 to address this issue. Your simple workaround for just setting the .Size explicitly should work until we have a fix available. Thank you again for the bug report.