Re: HTTPAPIR4 exception

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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