Bug 41729 - error message: ap_get_scoreboard_lb(130) failed in child ... for worker proxy:reverse
Summary: error message: ap_get_scoreboard_lb(130) failed in child ... for worker prox...
Alias: None
Product: Apache httpd-2
Classification: Unclassified
Component: mod_proxy (show other bugs)
Version: 2.2.4
Hardware: Other Linux
: P2 major with 10 votes (vote)
Target Milestone: ---
Assignee: Apache HTTPD Bugs Mailing List
Keywords: MassUpdate
Depends on:
Reported: 2007-02-28 07:07 UTC by gonono
Modified: 2018-11-07 21:09 UTC (History)
7 users (show)


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Description gonono 2007-02-28 07:07:24 UTC
hye everybody

in a apache 2.2.4 using proxyreverse 
there is every second a error line in the error_log

[Wed Feb 28 15:59:42 2007] [error] proxy: ap_get_scoreboard_lb(130) failed in 
child 28303 for worker proxy:reverse
Comment 1 Ruediger Pluem 2007-02-28 14:18:32 UTC
Please post your proxy configuration here. Did you do a graceful restart before
these messages appeared? Do the messages disappear after a hard stop and start?
Comment 2 gonono 2007-02-28 23:57:33 UTC
(In reply to comment #1)
> Please post your proxy configuration here. Did you do a graceful restart 
> these messages appeared? Do the messages disappear after a hard stop and 

Apparently, this messages appears every new child launched by Apache but not 
appear on startup or graceful command. it's appear on use, and start or stop 
has no effect on this bug......the message returns when the proxypass is 
used... but it doesn't impact on functionality

the proxy conf

<IfModule mod_proxy.c>
ProxyRequests Off
ProxyPass         /test/   http://xx.xx.xx.xx/work/
ProxyPassReverse  /test/   http://xx.xx.xx.xx/work/
ProxyVia On

load modules in http.conf : libphp.so mod_security.so libxml2.so

Compiled in modules: core.c  mod_authn_file.c  mod_authn_default.c  
mod_authz_host.c  mod_authz_groupfile.c  mod_authz_user.c  mod_authz_default.c
  mod_auth_basic.c  mod_include.c  mod_filter.c  mod_log_config.c  mod_env.c
  mod_unique_id.c  mod_setenvif.c  mod_proxy.c  mod_proxy_connect.c  
mod_proxy_ftp.c  mod_proxy_http.c  mod_proxy_ajp.c  mod_proxy_balancer.c
  mod_ssl.c  prefork.c  http_core.c  mod_mime.c  mod_status.c  mod_autoindex.c
  mod_asis.c  mod_cgi.c  mod_negotiation.c  mod_dir.c  mod_actions.c
  mod_userdir.c  mod_alias.c  mod_rewrite.c  mod_so.c

thanks for your reply
Comment 3 Ruediger Pluem 2007-03-01 13:21:02 UTC
Still strange. I am a little bit astonished by the number 130 in the error
message. Please let me know how many distinct ProxyPass directives you have in
your whole configuration (including all virtual hosts). Please let me also know
if you have configured balancers somewhere in your configuration and all <Proxy
> sections.
Comment 4 Glenn Nielsen 2008-01-07 07:18:21 UTC
I also see these errors in apache 2.2.6 on FreeBSD 6.2-RELEASE-p4 #0.

Mon Jan 07 08:59:36 2008] [error] proxy: ap_get_scoreboard_lb(325) failed in
child 49900 for worker proxy:reverse

We setup a reverse proxy for every virtual host for backend searches using a
google mini.

Each Virtual Host has two ProxyPass config lines. A grep of our VH configs shows
about 1000 ProxyPass config lines. These are split out between three different
HTTP servers.

I can confirm that this appears to happen once for each new httpd process.
Comment 5 Ruediger Pluem 2008-01-07 08:31:19 UTC
Do you have any third party modules installed in your configuration? It seems
that the child_init hook is called multiple times for the same child. Which MPM
are you using?
Comment 6 Anna Wiejak 2008-10-22 08:17:04 UTC

Exactly the same problem here. But it doesn't seem to be related (at least not in this case) to the way apache is restarted/reloaded.

After a short code-review .. I would say that the problem has something to do with thread-based apache configuration. It looks like each new httpd.worker child (up to the ServerLimit) is keeping it's own set of proxy workers, which, except the first set, are not counted in when scoreboard is preinitialized.

Can someone please look into the mod_proxy scoreboard problem?



Comment 7 Philp M. Gollucci 2009-01-18 16:19:17 UTC
CC myself on FreeBSD related bugs
Comment 8 Erik Hensema 2010-01-05 07:42:03 UTC
Is it possible this bug has a significant performance impact? (maybe caused by an fsync() after every log entry)

I experience tremendous load spikes on a server with numerous reverse proxies. I've got close to 600 ProxyPass statements in my apache config. The disk of the server is not very fast for writes. It's a virtual box connected to an iSCSI server which isn't too fast at the moment.
Comment 9 mephinet 2012-09-12 17:23:18 UTC
I also experience these error messages on one of my servers. The curious thing is, though, that mod_proxy isn't used at all on these servers, e.g., there is no VirtualHost section with a Proxy* directive.
Seen with Apache 2.2.3 on RHEL 5.6.
Comment 10 gio tex 2016-07-12 10:16:37 UTC
we have the same problem with openbsd 5.7 and apache 2.2.29, a line on error log for every proxy pass, every second
Comment 11 William A. Rowe Jr. 2018-11-07 21:09:51 UTC
Please help us to refine our list of open and current defects; this is a mass update of old and inactive Bugzilla reports which reflect user error, already resolved defects, and still-existing defects in httpd.

As repeatedly announced, the Apache HTTP Server Project has discontinued all development and patch review of the 2.2.x series of releases. The final release 2.2.34 was published in July 2017, and no further evaluation of bug reports or security risks will be considered or published for 2.2.x releases. All reports older than 2.4.x have been updated to status RESOLVED/LATER; no further action is expected unless the report still applies to a current version of httpd.

If your report represented a question or confusion about how to use an httpd feature, an unexpected server behavior, problems building or installing httpd, or working with an external component (a third party module, browser etc.) we ask you to start by bringing your question to the User Support and Discussion mailing list, see [https://httpd.apache.org/lists.html#http-users] for details. Include a link to this Bugzilla report for completeness with your question.

If your report was clearly a defect in httpd or a feature request, we ask that you retest using a modern httpd release (2.4.33 or later) released in the past year. If it can be reproduced, please reopen this bug and change the Version field above to the httpd version you have reconfirmed with.

Your help in identifying defects or enhancements still applicable to the current httpd server software release is greatly appreciated.