Re: Multiple RPC from same page gives Error 500
Hello Viju, How are you integrating GWT with Spring? I'm asking because Spring does bind controllers (which are not the same as servlets) to http, so there should not be any RemoteServiceServlet involved... bijuv v wrote: Hi George, The 500 error is explicitly set from the Google code (for unexepcted failure scenario). The code doesnt pass the RemoteServiceServlet to reach the application code. Before itself, the payload (output of the method readContentasUtf8) is empty. Due to this GWT is throwing the exception. The point Im trying to find is where the request is getting modified on its way before reaching the RemoteServiceServlet. BTW, there are filters in place, which is the SpringSecurityFilter Thanks Viju On Wed, Sep 29, 2010 at 1:22 PM, George Georgovassilis wrote: Hello GWTViju, I'm pretty sure you are running into a race condition. The 500 means that an error ocurred in the server side - there should be somewhere a detailed stacktrace, check your logging settings. Check for member variables in your controllers, servlets and services which could be modified by two parallel requests. A particularily uggly thing I've seen is if your controller references a single database connection which is then used by multiple requests in parallel. On Sep 28, 10:54 pm, bijuv v wrote: Able to reproduce the same without proxy setup as well. I directly hit the Websphere server (bypassing the proxy) and still get the same error. Though I say I can reproduce locally (tomcat ), the steps will vary each time. I have taken another step now - Im printing the payload in the Filters itself (just to make sure that the filters did not eat up the payload for whatever reason it is! I'm using Spring Security + 2 additional filters) -- You received this message because you are subscribed to the Google Groups "Google Web Toolkit" group. To post to this group, send email to google-web-tool...@googlegroups.com. To unsubscribe from this group, send email to google-web-toolkit+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-web-toolkit?hl=en. -- You received this message because you are subscribed to the Google Groups "Google Web Toolkit" group. To post to this group, send email to google-web-tool...@googlegroups.com. To unsubscribe from this group, send email to google-web-toolkit+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-web-toolkit?hl=en.
Re: Multiple RPC from same page gives Error 500
Hi George, The 500 error is explicitly set from the Google code (for unexepcted failure scenario). The code doesnt pass the RemoteServiceServlet to reach the application code. Before itself, the payload (output of the method readContentasUtf8) is empty. Due to this GWT is throwing the exception. The point Im trying to find is where the request is getting modified on its way before reaching the RemoteServiceServlet. BTW, there are filters in place, which is the SpringSecurityFilter Thanks Viju On Wed, Sep 29, 2010 at 1:22 PM, George Georgovassilis wrote: > Hello GWTViju, > > I'm pretty sure you are running into a race condition. The 500 means > that an error ocurred in the server side - there should be somewhere a > detailed stacktrace, check your logging settings. Check for member > variables in your controllers, servlets and services which could be > modified by two parallel requests. A particularily uggly thing I've > seen is if your controller references a single database connection > which is then used by multiple requests in parallel. > > On Sep 28, 10:54 pm, bijuv v wrote: >> Able to reproduce the same without proxy setup as well. I directly hit >> the Websphere server (bypassing the proxy) and still get the same >> error. >> >> Though I say I can reproduce locally (tomcat ), the steps will vary each >> time. >> >> I have taken another step now - Im printing the payload in the Filters >> itself (just to make sure that the filters did not eat up the payload >> for whatever reason it is! I'm using Spring Security + 2 additional >> filters) > > -- > You received this message because you are subscribed to the Google Groups > "Google Web Toolkit" group. > To post to this group, send email to google-web-tool...@googlegroups.com. > To unsubscribe from this group, send email to > google-web-toolkit+unsubscr...@googlegroups.com. > For more options, visit this group at > http://groups.google.com/group/google-web-toolkit?hl=en. > > -- You received this message because you are subscribed to the Google Groups "Google Web Toolkit" group. To post to this group, send email to google-web-tool...@googlegroups.com. To unsubscribe from this group, send email to google-web-toolkit+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-web-toolkit?hl=en.
Re: Multiple RPC from same page gives Error 500
Hello GWTViju, I'm pretty sure you are running into a race condition. The 500 means that an error ocurred in the server side - there should be somewhere a detailed stacktrace, check your logging settings. Check for member variables in your controllers, servlets and services which could be modified by two parallel requests. A particularily uggly thing I've seen is if your controller references a single database connection which is then used by multiple requests in parallel. On Sep 28, 10:54 pm, bijuv v wrote: > Able to reproduce the same without proxy setup as well. I directly hit > the Websphere server (bypassing the proxy) and still get the same > error. > > Though I say I can reproduce locally (tomcat ), the steps will vary each time. > > I have taken another step now - Im printing the payload in the Filters > itself (just to make sure that the filters did not eat up the payload > for whatever reason it is! I'm using Spring Security + 2 additional > filters) -- You received this message because you are subscribed to the Google Groups "Google Web Toolkit" group. To post to this group, send email to google-web-tool...@googlegroups.com. To unsubscribe from this group, send email to google-web-toolkit+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-web-toolkit?hl=en.
Re: Multiple RPC from same page gives Error 500
Able to reproduce the same without proxy setup as well. I directly hit the Websphere server (bypassing the proxy) and still get the same error. Though I say I can reproduce locally (tomcat ), the steps will vary each time. I have taken another step now - Im printing the payload in the Filters itself (just to make sure that the filters did not eat up the payload for whatever reason it is! I'm using Spring Security + 2 additional filters) -- You received this message because you are subscribed to the Google Groups "Google Web Toolkit" group. To post to this group, send email to google-web-tool...@googlegroups.com. To unsubscribe from this group, send email to google-web-toolkit+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-web-toolkit?hl=en.
Re: Multiple RPC from same page gives Error 500
I've only seen the framework optimize static resources. I'm using the GWT-Dispatch library which basically sequences a single RPC call many times per second (peak) to drive an appengine instance. I've had more luck sequencing actions rather than making multiple concurrent calls due to database conflicts and browser limitations. Can you reproduce this without the proxy setup? locally? On Tue, Sep 28, 2010 at 12:26 PM, bijuv v wrote: > Dear Andy, > Thanks much for the response. > > We get the 500 error immediately from the server. The payload is > coming as blank (empty value or "") in the RemoteServiceServlet. > Hence the GWT code is intentionally throwing the 500 error. The point > that I cant understand is why the payload is not reaching the server > though it has dispatched from the browser? I could see the request > details in the Firebug (Netspeed section) > > One more point is that , if I restrict the number of connections to a > single host as 1 (in firefox using about:config), the 500 error doesnt > appear as all RPC requests to the server are then sequenced. Well this > also doesnt give me a clue as to why simultaneous requests messes up > the payload when it reaches the server. > > Retry may be a solution but I feel that its a workaround (last option). > > Wondering if GWT optimizes in some way like if there are 4 RPC's sent > to same service in backend, does GWT merge the payload into one > request?? > > Thanks > Viju > > FWIW, your RPC calls just happen to use the HTTP protocol. > 500 responses are not unusual (especially most recently). > > If its immediate then you've pushing the limit of the browser's capacity; > at 30 seconds, its a harddeadline exception. > > The browser is single threaded and has a limited number of open > connections to the same host (2 or 4 I think). It is relatively easy > for a click happy user to overwhelm a long duration RPC handler. > Using push/pull libraries like Comet or Facebook take up capacity too. > Viju: We are not using the Comet or any of the push technolgies in the > application > > I've successfully used Microsoft's Fiddler proxy and HttpFox to trace > communication request/response issues both locally and on production > instances. > I suggest building in a simple retry solution and make sure your RPCs > are discrete. > > On Tue, Sep 28, 2010 at 9:00 PM, andy stevko > wrote: > > FWIW, your RPC calls just happen to use the HTTP protocol. > > 500 responses are not unusual (especially most recently). > > > > If its immediate then you've pushing the limit of the browser's capacity; > > at 30 seconds, its a harddeadline exception. > > > > The browser is single threaded and has a limited number of open > connections > > to the same host (2 or 4 I think). It is relatively easy for a click > happy > > user to overwhelm a long duration RPC handler. > > Using push/pull libraries like Comet or Facebook take up capacity too. > > > > I've successfully used Microsoft's Fiddler proxy and HttpFox to trace > > communication request/response issues both locally and on production > > instances. > > I suggest building in a simple retry solution and make sure your RPCs are > > discrete. > > > > > > > > On Mon, Sep 27, 2010 at 10:19 AM, GWTViju > wrote: > >> > >> e are using GWT 2.0.3 and Spring in the backend. Facing the below > >> issue in IE(6,7,8) as well as Firefox. A proxy is placed between the > >> Browser and the Application Server. > >> > >> In our application, we make multiple RPC calls to display the page. > >> The scenario is described below > >> > >> RPC A and RPC B is executed when a menu is clicked. RPC A and RPC B > >> are triggered in parallel. > >> When RPC A completes successfully, RPC C call is triggered. > >> When RPC B completes successfully, RPC D call is triggered. > >> > >> The RPC C and RPC D are not triggered in the onSuccess method. The > >> onSuccess transfers command to the browser, browser does some display > >> work and then fires off the associated RPC.. > >> The UI event then fires the RPC C and RPC D to the server. > >> > >> In some cases (not always), I get 'Error : 500:Server response is > >> invalid. Please re-try or contact admin.' > >> > >> I added some debug statements in my servlet and found that in such > >> error scenarios, the payload is returned as Empty. > >> The content length however gives a valid number like 199 or 223. > >> From the browser, I checked the request and the request has the > >> expected payload. > >> > >> 1. Is there an issue in chaining the RPC invocations to the server , > >> in my case, 4 RPC calls are made. > >> > >> 2. Has anyone seen a case in which the RPC request sent from the > >> browser is lost before it reaches the server? > >> > >> > >> Any help would be useful. > >> > >> -- > >> You received this message because you are subscribed to the Google > Groups > >> "Google Web Toolkit" group. > >> To post to this group, send email to > google-web-tool...@googlegroups.com. > >> To unsubscribe fro
Re: Multiple RPC from same page gives Error 500
Dear Andy, Thanks much for the response. We get the 500 error immediately from the server. The payload is coming as blank (empty value or "") in the RemoteServiceServlet. Hence the GWT code is intentionally throwing the 500 error. The point that I cant understand is why the payload is not reaching the server though it has dispatched from the browser? I could see the request details in the Firebug (Netspeed section) One more point is that , if I restrict the number of connections to a single host as 1 (in firefox using about:config), the 500 error doesnt appear as all RPC requests to the server are then sequenced. Well this also doesnt give me a clue as to why simultaneous requests messes up the payload when it reaches the server. Retry may be a solution but I feel that its a workaround (last option). Wondering if GWT optimizes in some way like if there are 4 RPC's sent to same service in backend, does GWT merge the payload into one request?? Thanks Viju FWIW, your RPC calls just happen to use the HTTP protocol. 500 responses are not unusual (especially most recently). If its immediate then you've pushing the limit of the browser's capacity; at 30 seconds, its a harddeadline exception. The browser is single threaded and has a limited number of open connections to the same host (2 or 4 I think). It is relatively easy for a click happy user to overwhelm a long duration RPC handler. Using push/pull libraries like Comet or Facebook take up capacity too. Viju: We are not using the Comet or any of the push technolgies in the application I've successfully used Microsoft's Fiddler proxy and HttpFox to trace communication request/response issues both locally and on production instances. I suggest building in a simple retry solution and make sure your RPCs are discrete. On Tue, Sep 28, 2010 at 9:00 PM, andy stevko wrote: > FWIW, your RPC calls just happen to use the HTTP protocol. > 500 responses are not unusual (especially most recently). > > If its immediate then you've pushing the limit of the browser's capacity; > at 30 seconds, its a harddeadline exception. > > The browser is single threaded and has a limited number of open connections > to the same host (2 or 4 I think). It is relatively easy for a click happy > user to overwhelm a long duration RPC handler. > Using push/pull libraries like Comet or Facebook take up capacity too. > > I've successfully used Microsoft's Fiddler proxy and HttpFox to trace > communication request/response issues both locally and on production > instances. > I suggest building in a simple retry solution and make sure your RPCs are > discrete. > > > > On Mon, Sep 27, 2010 at 10:19 AM, GWTViju wrote: >> >> e are using GWT 2.0.3 and Spring in the backend. Facing the below >> issue in IE(6,7,8) as well as Firefox. A proxy is placed between the >> Browser and the Application Server. >> >> In our application, we make multiple RPC calls to display the page. >> The scenario is described below >> >> RPC A and RPC B is executed when a menu is clicked. RPC A and RPC B >> are triggered in parallel. >> When RPC A completes successfully, RPC C call is triggered. >> When RPC B completes successfully, RPC D call is triggered. >> >> The RPC C and RPC D are not triggered in the onSuccess method. The >> onSuccess transfers command to the browser, browser does some display >> work and then fires off the associated RPC.. >> The UI event then fires the RPC C and RPC D to the server. >> >> In some cases (not always), I get 'Error : 500:Server response is >> invalid. Please re-try or contact admin.' >> >> I added some debug statements in my servlet and found that in such >> error scenarios, the payload is returned as Empty. >> The content length however gives a valid number like 199 or 223. >> From the browser, I checked the request and the request has the >> expected payload. >> >> 1. Is there an issue in chaining the RPC invocations to the server , >> in my case, 4 RPC calls are made. >> >> 2. Has anyone seen a case in which the RPC request sent from the >> browser is lost before it reaches the server? >> >> >> Any help would be useful. >> >> -- >> You received this message because you are subscribed to the Google Groups >> "Google Web Toolkit" group. >> To post to this group, send email to google-web-tool...@googlegroups.com. >> To unsubscribe from this group, send email to >> google-web-toolkit+unsubscr...@googlegroups.com. >> For more options, visit this group at >> http://groups.google.com/group/google-web-toolkit?hl=en. >> > > -- > You received this message because you are subscribed to the Google Groups > "Google Web Toolkit" group. > To post to this group, send email to google-web-tool...@googlegroups.com. > To unsubscribe from this group, send email to > google-web-toolkit+unsubscr...@googlegroups.com. > For more options, visit this group at > http://groups.google.com/group/google-web-toolkit?hl=en. > -- You received this message because you are subscribed to the Google Groups "G
Re: Multiple RPC from same page gives Error 500
FWIW, your RPC calls just happen to use the HTTP protocol. 500 responses are not unusual (especially most recently). If its immediate then you've pushing the limit of the browser's capacity; at 30 seconds, its a harddeadline exception. The browser is single threaded and has a limited number of open connections to the same host (2 or 4 I think). It is relatively easy for a click happy user to overwhelm a long duration RPC handler. Using push/pull libraries like Comet or Facebook take up capacity too. I've successfully used Microsoft's Fiddler proxy and HttpFox to trace communication request/response issues both locally and on production instances. I suggest building in a simple retry solution and make sure your RPCs are discrete. On Mon, Sep 27, 2010 at 10:19 AM, GWTViju wrote: > e are using GWT 2.0.3 and Spring in the backend. Facing the below > issue in IE(6,7,8) as well as Firefox. A proxy is placed between the > Browser and the Application Server. > > In our application, we make multiple RPC calls to display the page. > The scenario is described below > > RPC A and RPC B is executed when a menu is clicked. RPC A and RPC B > are triggered in parallel. > When RPC A completes successfully, RPC C call is triggered. > When RPC B completes successfully, RPC D call is triggered. > > The RPC C and RPC D are not triggered in the onSuccess method. The > onSuccess transfers command to the browser, browser does some display > work and then fires off the associated RPC.. > The UI event then fires the RPC C and RPC D to the server. > > In some cases (not always), I get 'Error : 500:Server response is > invalid. Please re-try or contact admin.' > > I added some debug statements in my servlet and found that in such > error scenarios, the payload is returned as Empty. > The content length however gives a valid number like 199 or 223. > From the browser, I checked the request and the request has the > expected payload. > > 1. Is there an issue in chaining the RPC invocations to the server , > in my case, 4 RPC calls are made. > > 2. Has anyone seen a case in which the RPC request sent from the > browser is lost before it reaches the server? > > > Any help would be useful. > > -- > You received this message because you are subscribed to the Google Groups > "Google Web Toolkit" group. > To post to this group, send email to google-web-tool...@googlegroups.com. > To unsubscribe from this group, send email to > google-web-toolkit+unsubscr...@googlegroups.com > . > For more options, visit this group at > http://groups.google.com/group/google-web-toolkit?hl=en. > > -- You received this message because you are subscribed to the Google Groups "Google Web Toolkit" group. To post to this group, send email to google-web-tool...@googlegroups.com. To unsubscribe from this group, send email to google-web-toolkit+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-web-toolkit?hl=en.
Re: Multiple RPC from same page gives Error 500
Dear All, We are using GWT 2.0.3 and Spring in the backend. Facing the below issue in IE(6,7,8) as well as Firefox. A proxy is placed between the Browser and the Application Server. In our application, we make multiple RPC calls to display the page. The scenario is described below RPC A and RPC B is executed when a menu is clicked. RPC A and RPC B are triggered in parallel. When RPC A completes successfully, RPC C call is triggered. When RPC B completes successfully, RPC D call is triggered. The RPC C and RPC D are not triggered in the onSuccess method. The onSuccess transfers command to the browser, browser does some display work and then fires off the associated RPC.. The UI event then fires the RPC C and RPC D to the server. In some cases (not always), I get 'Error : 500:Server response is invalid. Please re-try or contact admin.' I added some debug statements in my servlet and found that in such error scenarios, the payload is returned as Empty. The content length however gives a valid number like 199 or 223. >From the browser, I checked the request and the request has the expected payload. 1. Is there an issue in chaining the RPC invocations to the server , in my case, 4 RPC calls are made. 2. Has anyone seen a case in which the RPC request sent from the browser is lost before it reaches the server? Any help would be useful. Thanks Viju -- You received this message because you are subscribed to the Google Groups "Google Web Toolkit" group. To post to this group, send email to google-web-tool...@googlegroups.com. To unsubscribe from this group, send email to google-web-toolkit+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-web-toolkit?hl=en.
Multiple RPC from same page gives Error 500
e are using GWT 2.0.3 and Spring in the backend. Facing the below issue in IE(6,7,8) as well as Firefox. A proxy is placed between the Browser and the Application Server. In our application, we make multiple RPC calls to display the page. The scenario is described below RPC A and RPC B is executed when a menu is clicked. RPC A and RPC B are triggered in parallel. When RPC A completes successfully, RPC C call is triggered. When RPC B completes successfully, RPC D call is triggered. The RPC C and RPC D are not triggered in the onSuccess method. The onSuccess transfers command to the browser, browser does some display work and then fires off the associated RPC.. The UI event then fires the RPC C and RPC D to the server. In some cases (not always), I get 'Error : 500:Server response is invalid. Please re-try or contact admin.' I added some debug statements in my servlet and found that in such error scenarios, the payload is returned as Empty. The content length however gives a valid number like 199 or 223. >From the browser, I checked the request and the request has the expected payload. 1. Is there an issue in chaining the RPC invocations to the server , in my case, 4 RPC calls are made. 2. Has anyone seen a case in which the RPC request sent from the browser is lost before it reaches the server? Any help would be useful. -- You received this message because you are subscribed to the Google Groups "Google Web Toolkit" group. To post to this group, send email to google-web-tool...@googlegroups.com. To unsubscribe from this group, send email to google-web-toolkit+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-web-toolkit?hl=en.
