On 2011-08-21, at 12:43 PM, Tim Worman wrote: > On Aug 21, 2011, at 11:52 AM, Chuck Hill wrote: > >> >> On 2011-08-20, at 4:02 PM, Tim Worman wrote: >> >>> Back in January I started this discussion on this same topic: >>> >>> http://lists.apple.com/archives/webobjects-dev/2011/Jan/msg00224.html >>> >>>>> I have an app that, during the course of normal usage, is starting httpd >>>>> processes on the server that instantly hit 100% CPU usage of one core. >>>>> This can happen multiple times during times when the app is under heavier >>>>> load. After some time I can have many httpd processes where TOP reports >>>>> each using 100% of a core. When I try to log into the app and poke around >>>>> to try and reproduce the issue, I am unable. >>> >>> This is an update to my original post hoping to see if there are anymore >>> thoughts on origin. More recently, I have been able to reproduce the issue >>> in my own usage of the app - something I wasn't able to do before. It seems >>> to be easier to generate the issue now that there are more ajax requests. >>> The methods executed by these requests are not intensive or long responses >>> and should return a result in seconds. Some symptoms: >>> >>> - When the actions are executed, busy indicators properly spin while the >>> browser awaits a response from the server. When the issue occurs, the >>> response never comes. >>> - while continuing to await a response there is concurrently an httpd >>> process that pegs he processor at 100% >>> - if I kill the process on the server, the browser immediately updates >>> properly as if the request had run properly >>> >>> It's almost as if apache is somehow receiving an ill-formed request and >>> chokes on it. The problem is, there are no errors in the console or >>> anything strange in any apache logs. Has anyone ever seen behavior like >>> this or have any ideas as to how I could analyze it further? >> >> I've seen something like this. It appeared that the woadaptor (i.e. >> mod_webobjects) did not believe that it had received all of the response >> from the application. The app had nothing more to send and so the woadaptor >> just hung there waiting for data that would never come. I did not track >> down why this happened, but it did seem to be load related. My suspicion >> was that there is a concurrency bug in the woadaptor. > > I'm really at a loss about what to do about it. It's only gotten worse as > I've included more ajax actions in my app - and, of course, I don't > experience this behavior in development. I just deployed a major update to my > app - pretty much unaware that a small problem was going to become a big > problem with the new version. > > In one example, a have a calendar where clicking on a day simply calls an > AjaxUpdate marking that date as selected to the calendar. The result also has > to update the entire page though because other things on the page need to > change in those circumstances. This alone can cause the issue - but not > always. And it happens even when I'm the only logged in user - so the load > isn't high. > > As one solution, I've considered rolling a custom apache instead of using > Apple's. But since the server also runs shibboleth, the setup isn't exactly > simple. But I'm really not sure how to ascertain if the problem is the > woadaptor or how I can settle it.
You could try the CGI adaptor and see if that makes any difference. If it IS a bug in mod_webobjects... that could be hard to find and fix. Chuck -- Chuck Hill Senior Consultant / VP Development Practical WebObjects - for developers who want to increase their overall knowledge of WebObjects or who are trying to solve specific problems. http://www.global-village.net/products/practical_webobjects _______________________________________________ Do not post admin requests to the list. They will be ignored. Webobjects-dev mailing list ([email protected]) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/webobjects-dev/archive%40mail-archive.com This email sent to [email protected]
