PM98613: PROXY SERVER MAY NOT RELEASE RESOURCES WHEN AN ENDPOINT IS UNAVAILABLE

Fixes are available

APAR status

Closed as program error.

Error description

When an endpoint is unavailable, workload management (WLM)
tells the proxy server to suspend  the request and it
schedules a thread to resume the request when endpoint data is
available.
.
WLM does not check the return code to see if the thread
was scheduled successfully.  If the thread is not scheduled
because the thread pool is full, the request won't be
resumed which could lead to a loss of resources, such
as the incoming socket.
.
The following message appears in the log.
.
WSVR0629I: The request buffer for thread pool "Default" has
reached its capacity.
.
The following FFDC appears.
.
com.ibm.ws.util.ThreadPool$ThreadPoolQueueIsFullException
at com.ibm.ws.util.ThreadPool.execute(ThreadPool.java:1386)
at com.ibm.ws.util.ThreadPool.execute(ThreadPool.java:1171)
at
com.ibm.ws.runtime.WSThreadPool.execute(WSThreadPool.java:93)
at
com.ibm.ws.proxy.filter.ucf.UCFHttpRouterFilter.preInvoke(UCFHtt
pRouterFilter.java:819)
at
com.ibm.ws.proxy.filter.ucf.UCFHttpRouterFilter.doFilter(UCFHttp
RouterFilter.java:536)
at
com.ibm.ws.proxy.filter.http.HttpFilterImpl.doFilter(HttpFilterI
mpl.java:98)
at
com.ibm.ws.proxy.filter.http.HttpFilterChain.doRequestFilterChai
n(HttpFilterChain.java:343)
at
com.ibm.ws.proxy.filter.http.HttpFilterChain.doRequestFilterChai
nWrapper(HttpFilterChain.java:263)
at
com.ibm.ws.proxy.filter.http.HttpFilterChain.doRequestFilterChai
n(HttpFilterChain.java:242)
at
com.ibm.ws.proxy.channel.http.HttpProxyConnectionLink.processReq
uestWork(HttpProxyConnectionLink.java:567)
at
com.ibm.ws.proxy.channel.http.HttpProxyConnectionLink.ready(Http
ProxyConnectionLink.java:330)
at
com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleDiscr
imination(HttpInboundLink.java:453)
at
..
..

Local fix

```
na
```

Problem summary

****************************************************************
* USERS AFFECTED:  All users of IBM WebSphere Application      *
*                  Server Proxy Server                         *
****************************************************************
* PROBLEM DESCRIPTION: WLM running in a proxy server may       *
*                      encounter ThreadPoolFullException       *
*                      when an endpoint is unavailable,        *
*                      however WLM does not handle the         *
*                      ThreadPoolFullException properly        *
*                      which may result in the loss of         *
*                      resources, such as an incoming socket.  *
****************************************************************
* RECOMMENDATION:                                              *
****************************************************************
When an endpoint is unavailable, workload management (WLM)
tells the proxy server to suspend the request and it
schedules a thread to resume the request when endpoint data is
available. However, WLM does not check the return code to see
if the thread was scheduled successfully. If the thread is not
scheduled because the thread pool is full, the request won't
be resumed which could lead to a loss of resources, such as
the incoming socket.
The following message appears in the log.
WSVR0629I: The request buffer for thread pool "Default" has
reached its capacity.
The following FFDC appears.
com.ibm.ws.util.ThreadPool$ThreadPoolQueueIsFullException
at com.ibm.ws.util.ThreadPool.execute(ThreadPool.java:1386)
at com.ibm.ws.util.ThreadPool.execute(ThreadPool.java:1171)
at
com.ibm.ws.runtime.WSThreadPool.execute(WSThreadPool.java:93)
at
com.ibm.ws.proxy.filter.ucf.UCFHttpRouterFilter.preInvoke(UCFHtt
pRouterFilter.java:819)
at
com.ibm.ws.proxy.filter.ucf.UCFHttpRouterFilter.doFilter(UCFHttp
RouterFilter.java:536)
at
com.ibm.ws.proxy.filter.http.HttpFilterImpl.doFilter(HttpFilterI
mpl.java:98)
at
com.ibm.ws.proxy.filter.http.HttpFilterChain.doRequestFilterChai
n(HttpFilterChain.java:343)
at
com.ibm.ws.proxy.filter.http.HttpFilterChain.doRequestFilterChai
nWrapper(HttpFilterChain.java:263)
at
com.ibm.ws.proxy.filter.http.HttpFilterChain.doRequestFilterChai
n(HttpFilterChain.java:242)
at
com.ibm.ws.proxy.channel.http.HttpProxyConnectionLink.processReq
uestWork(HttpProxyConnectionLink.java:567)
at
com.ibm.ws.proxy.channel.http.HttpProxyConnectionLink.ready(Http
ProxyConnectionLink.java:330)
at
com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleDiscr
imination(HttpInboundLink.java:453)
at
com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleNewRe
quest(HttpInboundLink.java:515)
at
com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.processRequ
est(HttpInboundLink.java:306)
at
com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.ready(HttpI
nboundLink.java:277)
at
com.ibm.ws.tcp.channel.impl.NewConnectionInitialReadCallback.sen
dToDiscriminators(NewConnectionInitialReadCallback.java:214)
at
com.ibm.ws.tcp.channel.impl.NewConnectionInitialReadCallback.com
plete(NewConnectionInitialReadCallback.java:113)
at
com.ibm.ws.tcp.channel.impl.AioReadCompletionListener.futureComp
leted(AioReadCompletionListener.java:175)
at
com.ibm.io.async.AbstractAsyncFuture.invokeCallback(AbstractAsyn
cFuture.java:217)
at
com.ibm.io.async.AsyncChannelFuture.fireCompletionActions(AsyncC
hannelFuture.java:161)
at com.ibm.io.async.AsyncFuture.completed(AsyncFuture.java:138)
at
com.ibm.io.async.ResultHandler.complete(ResultHandler.java:204)
at
com.ibm.io.async.ResultHandler.runEventProcessingLoop(ResultHand
ler.java:816)
at com.ibm.io.async.ResultHandler$2.run(ResultHandler.java:905)
at com.ibm.ws.util.ThreadPool$Worker.run(ThreadPool.java:1700)

Problem conclusion

WLM has been corrected to properly handle the
ThreadPoolFullException. If a thread cannot be scheduled
because the thread pool is full, WLM will return an http 503
to the proxy server. This is considered normal and expected
behavior in this case. You should tune thread pool and
other resources as needed.

The fix for this APAR is currently targeted for inclusion in
fix packs 7.0.0.39, 8.0.0.8 and 8.5.5.2.  Please refer to the
Recommended Updates page for delivery information:
http://www.ibm.com/support/docview.wss?rs=180&uid=swg27004980

Temporary fix

Comments

APAR Information

APAR number
PM98613
Reported component name
WEBS APP SERV N
Reported component ID
5724H8800
Reported release
800
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2013-10-07
Closed date
2013-10-24
Last modified date
2015-11-04

APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:

Fix information

Fixed component name
WEBS APP SERV N
Fixed component ID
5724H8800

Applicable component levels

R800 PSY
UP
R850 PSY
UP

[{"Business Unit":{"code":"BU059","label":"IBM Software w\/o TPS"},"Product":{"code":"SSEQTP","label":"WebSphere Application Server"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"8.0","Line of Business":{"code":"LOB45","label":"Automation"}}]

Document Information

Modified date:
28 April 2022

Tips

PM98613: PROXY SERVER MAY NOT RELEASE RESOURCES WHEN AN ENDPOINT IS UNAVAILABLE

Fixes are available

Subscribe

APAR status

Closed as program error.

Error description

Local fix

Problem summary

Problem conclusion

Temporary fix

Comments

APAR Information

APAR number

Reported component name

Reported component ID

Reported release

Status

PE

HIPER

Special Attention

Submitted date

Closed date

Last modified date

APAR is sysrouted FROM one or more of the following:

APAR is sysrouted TO one or more of the following:

Fix information

Fixed component name

Fixed component ID

Applicable component levels

R800 PSY

R850 PSY

Document Information

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