I think I encountered a bug with sp_execute_external_script, so here is the replay.
I will get an error if I run the following script:
-- error occurs
exec sp_execute_external_script @language=N'R'
, @script = N' result <- as.data.frame(c(i, j));'
, @params = N'@i varchar(100), @j varchar(100)'
, @i = 'hello'
, @j = 'world'
, @output_data_1_name = N'result' -- the position of this param caused problem
with result sets ((test varchar(100)));
I will get an error
Msg 8144, Level 16, State 2, Line 1
Procedure or function has too many arguments specified.
However, if I just move up the @output_data_1_name
like the following:
-- NO error occurs
exec sp_execute_external_script @language=N'R'
, @script = N' result <- as.data.frame(c(i, j));'
, @output_data_1_name = N'result' -- this position in front of @parms caused NO problem
, @params = N'@i varchar(100), @j varchar(100)'
, @i = 'hello'
, @j = 'world'
with result sets ((test varchar(100)));
I will get a normal output:
Does anyone know whether I am doing something wrong or it indeed could be a bug in SQL Server 2016?
My environment is (by select @@version
):
Microsoft SQL Server 2016 (SP1-CU1) (KB3208177) - 13.0.4411.0 (X64)
Jan 6 2017 14:24:37
Copyright (c) Microsoft Corporation
Developer Edition (64-bit) on Windows 10 Pro 6.3 <X64> (Build 14393: )
Update:
I tested a little bit more and indeed the position of parameters will cause errors, such as following:
exec sp_execute_external_script
@script = N' result <- as.data.frame(c(i, j));'
, @output_data_1_name = N'result' -- the position of this param caused NO problem
, @params = N'@i varchar(100), @j varchar(100)'
, @i = N'hello'
, @j = N'world'
, @language=N'R' -- if I put @language here, it will cause error
with result sets ((test varchar(100)));
or this:
exec sp_execute_external_script @language=N'R'
, @script = N' result <- as.data.frame(c(i, j));'
, @output_data_1_name = N'result' -- the position of this param caused NO problem
, @i = N'hello'
, @j = N'world'
, @params = N'@i varchar(100), @j varchar(100)'
with result sets ((test varchar(100)));
The error message will be:
Msg 214, Level 16, State 175, Procedure sp_execute_external_script, Line 1 [Batch Start Line 19]
Procedure expects parameter '@params' of type 'ntext/nchar/nvarchar'.
But I actually give each parameter of type nvarchar
already.
I will consider open a bug report to MS if I do not see anyone pointing out my "errors".
Best Answer
The parameter list in
@params
can have names matching the names of the parameters used by thesp_execute_external_script
procedure itself, like@script
or@language
, for instance. There would need to be a way, then, to determine whether a parameter pertains to the system SP or to the user script.Making it a rule that
@params
be always specified last in the list of the parameters pertaining tosp_execute_external_script
and all the parameters specified after@params
be considered pertaining to the user script is one easy way to implement the distinction. So, if a parameter like@language
is specified after@params
, it will be interpreted as a script parameter and not the SP's parameter.And I believe that is what is happening in the cases where you are specifying
@output_data_1_name
or@language
after@params
. Those parameters simply must go before@params
to avoid potential ambiguity.Granted, there is not a word about this in the manual, which, however, is a problem with the manual more than a problem with
sp_execute_external_script
.