I'm starting to use Gearman to get around this whole problem. We use a lot of external processes for many things, so this issue wtih Apache2 really bit me hard in the bee-hind. I've gone to great lengths to work around it, but so far the job queue approach seems to be the most elegant and least problematic approach. Of course, the recommendation came from the gentle folks on this list originally.
Eric ________________________________ From: Heiko Weber [mailto:he...@wecos.de] Sent: Thursday, February 18, 2010 3:22 AM To: Salvador Ortiz Garcia Cc: mod_perl list Subject: Re: [mp2] mod_perl closes apache's stdin and/or stdout Salvador, to avoid such issues my "external" tasks don't use STDOUT, STDIN or STDERR. They take their parameters from control files and write their results back to a status file. This tasks don't send any output back to the browsers. As I said, usually some "sudo's to change some system settings. Well, I could replace all system() calls and just store the task jobs into a database table, to schedule a background job with cron to check and complete this tasks, but then I lost the immediately feedback to the user/browser ... AND this is a lot of work for me - unless I can exactly repeat the issue I am not sure if it is worth to try it. Currently it feels to me like a "leakage", sometimes a httpd/mod_perl/process do something, and later (maybe when working on the next client request) STDOUT is closed. This makes it hard to create a sample program to repeat it. Within a single script I can do almost everything: call system(), open DBI connections, write to STDOUT, ... everything seems to be fine. Heiko Am 16.02.2010 um 23:26 schrieb Salvador Ortiz Garcia: On 02/05/2010 12:16 PM, Heiko Weber wrote: Hi André, I know what you mean, and I can't agree with you - the server response time is really low - most pages are finished loading in less 1-2 seconds, and the overall load of the server is at a low level. I believe there is an issue, maybe something what Jon is talking about, I also using some "system()" call's to execute sendmail or sudo tasks, so maybe STDOUT really gets closed - I have no idea. I only see the abort messages in errorlog very frequent, maybe 3-4 per minute. Heiko Of course STDOUT, STDIN, and STDERR get closed, not by mod_perl but by apache. Every UNIX process when demonized must close them to detach from its controling terminal. Apache reopens STDERR to its log file, but STDOUT and STDIN remain closed. Maybe de confusion arises from the fact that when executing a CGI the server connects them to the client socket, but in mod_perl you are in the deamon process space. Please check "Advanced Programing in the UNIX environment", chapter 13: "Daemon processes" by W. Richard Stevens. Regards. Salvador. -- Wecos <> Heiko Weber Computer Systeme D-21644 Sauensiek <> Immenweg 5 he...@wecos.de<mailto:he...@wecos.de> <> http://www.wecos.de<http://www.wecos.de/> _______________________________________________ This e-mail may contain information that is confidential, privileged or otherwise protected from disclosure. If you are not an intended recipient of this e-mail, do not duplicate or redistribute it by any means. Please delete it and any attachments and notify the sender that you have received it in error. Unless specifically indicated, this e-mail is not an offer to buy or sell or a solicitation to buy or sell any securities, investment products or other financial product or service, an official confirmation of any transaction, or an official statement of Barclays. Any views or opinions presented are solely those of the author and do not necessarily represent those of Barclays. This e-mail is subject to terms available at the following link: www.barcap.com/emaildisclaimer. By messaging with Barclays you consent to the foregoing. Barclays Capital is the investment banking division of Barclays Bank PLC, a company registered in England (number 1026167) with its registered office at 1 Churchill Place, London, E14 5HP. This email may relate to or be sent from other members of the Barclays Group. _______________________________________________
