PQ74029: BACKLOG PARAMETER FOR LISTEN() WILL BE USER-CONFIGURABLE.

 A fix may be available

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APAR status
Closed as program error.

Error description
The symptom is that you can get ECONNREFUSED errors at the
client when trying to connect to WebSphere.

Issue IPCS command:
"IP TCPIPCS TCB" scroll down a couple pages to find the list of
current connections in the system.
i.e.: J2EE servers socket:
7F5D3508 000244EF BBOASR2A Listening   WLOIDLE  0.0.0.0..8084
Now using the first field, termed the "TCB" in command:
"IP TCPIPCS TCB(7F5D3508 DETAIL)"
Here, the TCB_MAX_BACKLOG looks like:
+0220  TCB_MAX_BACKLOG......... 0000000A
+0224  TCB_CURR_BACKLOG........ 00000000
+0228  TCB_EXCEED_BACKLOG...... 00000098
  So, the BACKLOG is set to 10 and it exceeded the backlog at an
one instance in time by '98'x or 152.
ECONNREFUSED is seen in the plugin, the server is marked not
available for period of time.  A reattempt to connect to the J2E
J2EE server can occur, and if successful, the server is marked
"up".  During the period of time the server is marked down, all
requests will get the 500 error, unless there are other servers
that are "up".
Local fix Problem summary
****************************************************************
* USERS AFFECTED: All users of WebSphere Application Server    *
*                 V4.0.1 for z/OS and OS/390                   *
****************************************************************
* PROBLEM DESCRIPTION: ECONNREFUSED errors at the client when  *
*                      trying to connect to WebSphere.         *
****************************************************************
* RECOMMENDATION:                                              *
****************************************************************
If a large number of concurrent connection requests are received
by the server, they can be rejected with  ECONNREFUSED whatever
if the backlog of unprocessed connection requests exceeds the
defined limit which is fixed at 10.
Problem conclusion
Four environment variables have been added added to
define number of backlog connections which can occur before
a connection refused condition reults. Documentation for these
new envirionment varibles follows:

APAR PQ74029 requires a change to V4.0.1 WebSphere for z/OS:
Installation and Customization, GA22-7834-04 will be available
in the next refresh of the documentation. To access the latest
online documentation, go to the product library page at:

www.ibm.com/software/webservers/appserv/zos_os390/

The change is to the table on page 396, which now reads:

|--------------------------------------------------------------|
| Env variable=<default>   | Dmn | SM  | Nam | IR  | App | zOS |
|--------------------------------------------------------------|
| ...                      |     |     |     |     |     |     |
|--------------------------------------------------------------|
| BBOC_HTTP_BACKLOG=10     | O   | O   | O   | O   | O   |     |
|--------------------------------------------------------------|
| BBOC_HTTPS_BACKLOG=10    | O   | O   | O   | O   | O   |     |
|--------------------------------------------------------------|
| ...                      |     |     |     |     |     |     |
|--------------------------------------------------------------|
| BBOC_IIOP_BACKLOG=10     | O   | O   | O   | O   | O   |     |
|--------------------------------------------------------------|
| BBOC_IIOPSSL_BACKLOG=10  | O   | O   | O   | O   | O   |     |
|--------------------------------------------------------------|
| ...                      |     |     |     |     |     |     |
|--------------------------------------------------------------|

and text starting on page 404, which now reads:

BBOC_HTTP_BACKLOG=n
An integer value that indicates the maximum queue length for
pending connections that use HTTP. You may set the maximum value
up to 2147483647, but the specification of the SOMAXCONN
statement in the TCP/IP profile may result in limitations to
this. The default is 10.
Example:
BBOC_HTTP_BACKLOG=25

BBOC_HTTPS_BACKLOG=n
An integer value that indicates the maximum queue length for
pending connections that use HTTPS. You may set the maximum
value up to 2147483647, but the specification of the SOMAXCONN
statement in the TCP/IP profile may result in limitations to
this. The default is 10.
Example:
BBOC_HTTPS_BACKLOG=25

BBOC_IIOP_BACKLOG=n
An integer value that indicates the maximum queue length for
pending connections that use IIOP. You may set the maximum value
up to 2147483647, but the specification of the SOMAXCONN
statement in the TCP/IP profile may result in limitations to
this. The default is 10.
Example:
BBOC_IIOP_BACKLOG=25

BBOC_IIOPSSL_BACKLOG=n
An integer value that indicates the maximum queue length for
pending connections that use IIOP SSL. You may set the maximum
value up to 2147483647, but the specification of the SOMAXCONN
statement in the TCP/IP profile may result in limitations to
this. The default is 10.
Example:
BBOC_IIOPSSL_BACKLOG=25


APAR PQ74029 is associated with SERVICE LEVEL W401507 of
WebSphere Application Server V4.0.1 for z/OS and OS/390.
Temporary fix Comments
APAR information
APAR number PQ74029
Reported component name WASKBASE
Reported component ID 5655A9801
Reported release 401
Status CLOSED PER
PE NoPE
HIPER NoHIPER
Submitted date 2003-05-09
Closed date 2003-06-16
Last modified date 2003-07-03

APAR is sysrouted FROM one or more of the following:

APAR is sysrouted TO one or more of the following:

Modules/Macros
BBOUBINF          

Fix information
Fixed component name WASKBASE
Fixed component ID 5655A9801

Applicable component levels
R401 PSY UQ77728    UP03/06/20 P F306

  Fix is available
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Document Information


Product categories: Software > Application Servers > Distributed Application & Web Servers > WebSphere Application Server for z/OS
Operating system(s):
Software version: 401
Software edition:
Reference #: PQ74029
IBM Group: Software Group
Modified date: Jul 3, 2003