Re: HTTPAPIR4 exception

[Scott Klement <rpg400-l@xxxxxxxxxxxxxxxx>]

Hi Peter,

The Unix-type APIs use something called a "Descriptor".  Every time a 
new IFS file is opened, a new socket is created or a new pipe is opened, 
it uses a new descriptor.

There's a limit to how many descriptors you can have open in a single 
job.  To me, it sounds like you are exceeding that limit.  Perhaps 
somewhere in your process, you are opening a stream file and forgetting 
to close it?  Thus it's staying open, and HTTPAPI is running out of 
descriptors?

That's what the error sounds like, to me.  HTTPAPI can only handle 
descriptor numbers up to number 223.  IF you have more open than that, 
it will produce the error you describe.

In my experience, programs under OS/400 don't normally have that many 
descriptors open at the same time.  If for some reason they do, it's a 
sure sign that a developer is accidentally leaving files open, and is 
running out of descriptors...

-SK


Peter Connell wrote:
> Hi,
>
> We are now getting intermittent exceptions occurring during HTTPAPIR4
> execution on our production HTTP server.
>
> Strangely, this is occurring during the connection for one particular
> service, others appear OK.
>
> Yet we have not made any changes to the service itself and certainly not
> changed the HTTPAPIR4 interface which is robust.
>
>  
>
> What has changed is the application layer from which the service is
> invoked.
>
>  A significant change is that layer now includes xml parsing via a java
> transformation class invoked from RPGLE.
>
>  
>
> I'm at a loss to understand what is happening and wondering if it is
> possible that there is some corruption of memory or file descriptor
> occurring outside of the control of the HTTPAPIR4 interface as I trust
> that there is no inherent error within that.
>
>  
>
> I do employ  the recommended "java frame" approach to managing java
> objects by beginning and ending an object group.
>
> I also recall seeing some similar "Klement" code that also made
> reference to the need to open 3 file descriptors during the JVM
> instantiation.
>
> I don't remember the need for this but perhaps it may be relevant to the
> error arising elsewhere in the HTTPAPIR4 interface.
>
>  
>
> I have thought that maybe running HTTPAPIR4 in it's own activation group
> help.
>
>  
>
> The HTTPAPIR4 exception is below.
>
>  
>
>  
>
> SEV  DATE      TIME             FROM PGM     LIBRARY     INST     TO PGM
> LIBRARY     INST       
>
> 50   11/08/09  09:06:44.171496  QRNXIE       QSYS        *STMT
> HTTPAPIR4   LIBHTTP     *STMT   
>
>   From user . . . . . . . . . :   QTMHHTP1
>
>
>   From module . . . . . . . . :   QRNXMSG
>
>
>   From procedure  . . . . . . :   SignalException
>
>
>   Statement . . . . . . . . . :   20
>
>
>   To module . . . . . . . . . :   COMMTCPR4
>
>
>   To procedure  . . . . . . . :   COMMTCP_FD_SET
>
>
>   Statement . . . . . . . . . :   4659
>
>
>   Message . . . . :   Length or start position is out of range for the
> string                        
>
>     operation.
>
>
>   Cause . . . . . :   One of the following has occurred in RPG procedure
>
>
>     COMMTCP_FD in program LIBHTTP/HTTPAPIR4: - A numeric length or start
>
>
>     position is less than 1 or too large for the string operation. - The
>
>
>     search-argument parameter of the %SCAN built-in function has zero
> length or                      
>
>     is longer than the source-string parameter. - The maximum-length
> parameter                       
>
>     of the %STR built-in function is not a value between 1 and the
> maximum size                      
>
>     of a character field. Recovery  . . . :   Contact the person
> responsible for                     
>
>     program maintenance to determine the cause of the problem.
>
>
>
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