[google-appengine] Re: GqlQuery bind method - is it safe to share the same query instance between requests?
Be aware that the value of a global variable is not known at the start of a request. It could be the value from the previous request if the interpreter was already warm/running. It would be the initial value if the interpreter was started cold. Why not put the GQL object in the request handler self.gql1= GqlQuery(...) or just a local variable? How often do you bind new values to the query for each request? 2008/12/17 Alex Epshteyn alexander.epsht...@gmail.com: Ah, I see. It's safe because a new request will not be processed by the same instance of the python interpreter until the previous request has fully completed, right? Thanks, Ryan! On Dec 16, 7:37 pm, Ryan Barrett goo...@ryanb.org wrote: hi alex! you're right to be cautious, but happily, requests are not handled by different threads. our python interpreters are single threaded, and handle only a single request at a time. more: http://code.google.com/appengine/docs/python/sandbox.htmlhttp://groups.google.com/group/google-appengine/browse_thread/thread/... given that, you don't need to worry about concurrent accesses to the query global variable, so this should be safe. even better, fetch() re- runs the query from the beginning, so if the parameters are the same across requests, you don't even need to bind() each time. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Google App Engine group. To post to this group, send email to google-appengine@googlegroups.com To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en -~--~~~~--~~--~--~---
[google-appengine] Re: GqlQuery bind method - is it safe to share the same query instance between requests?
The advantage of caching GqlQuery objects between requests is that it saves on having to compile the GQL for future requests. By storing it in a global and binding new values prior to calling, it gets compiled on the first request for the web server instance, and uses the pre-compiled version on subsequent requests. The only caveat is that you must remember to bind values prior to executing the query (calling fetch(), get() or using the iterator interface). If you call without binding, it might use values bound during a previous request. -- Dan On Sat, Dec 20, 2008 at 3:25 AM, djidjadji djidja...@gmail.com wrote: Be aware that the value of a global variable is not known at the start of a request. It could be the value from the previous request if the interpreter was already warm/running. It would be the initial value if the interpreter was started cold. Why not put the GQL object in the request handler self.gql1= GqlQuery(...) or just a local variable? How often do you bind new values to the query for each request? 2008/12/17 Alex Epshteyn alexander.epsht...@gmail.com: Ah, I see. It's safe because a new request will not be processed by the same instance of the python interpreter until the previous request has fully completed, right? Thanks, Ryan! On Dec 16, 7:37 pm, Ryan Barrett goo...@ryanb.org wrote: hi alex! you're right to be cautious, but happily, requests are not handled by different threads. our python interpreters are single threaded, and handle only a single request at a time. more: http://code.google.com/appengine/docs/python/sandbox.htmlhttp://groups.google.com/group/google-appengine/browse_thread/thread/. .. given that, you don't need to worry about concurrent accesses to the query global variable, so this should be safe. even better, fetch() re- runs the query from the beginning, so if the parameters are the same across requests, you don't even need to bind() each time. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Google App Engine group. To post to this group, send email to google-appengine@googlegroups.com To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en -~--~~~~--~~--~--~---
[google-appengine] Re: GqlQuery bind method - is it safe to share the same query instance between requests?
hi alex! you're right to be cautious, but happily, requests are not handled by different threads. our python interpreters are single threaded, and handle only a single request at a time. more: http://code.google.com/appengine/docs/python/sandbox.html http://groups.google.com/group/google-appengine/browse_thread/thread/3f8cfeaf7dc2eb72/7a5918d69158ae1b?#7a5918d69158ae1b given that, you don't need to worry about concurrent accesses to the query global variable, so this should be safe. even better, fetch() re- runs the query from the beginning, so if the parameters are the same across requests, you don't even need to bind() each time. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Google App Engine group. To post to this group, send email to google-appengine@googlegroups.com To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en -~--~~~~--~~--~--~---
[google-appengine] Re: GqlQuery bind method - is it safe to share the same query instance between requests?
Ah, I see. It's safe because a new request will not be processed by the same instance of the python interpreter until the previous request has fully completed, right? Thanks, Ryan! On Dec 16, 7:37 pm, Ryan Barrett goo...@ryanb.org wrote: hi alex! you're right to be cautious, but happily, requests are not handled by different threads. our python interpreters are single threaded, and handle only a single request at a time. more: http://code.google.com/appengine/docs/python/sandbox.htmlhttp://groups.google.com/group/google-appengine/browse_thread/thread/... given that, you don't need to worry about concurrent accesses to the query global variable, so this should be safe. even better, fetch() re- runs the query from the beginning, so if the parameters are the same across requests, you don't even need to bind() each time. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Google App Engine group. To post to this group, send email to google-appengine@googlegroups.com To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en -~--~~~~--~~--~--~---
