On Fri, Apr 24, 2015 at 7:32 AM, George Neuner <gneun...@comcast.net> wrote: > Hi Jay, > > On 4/24/2015 7:03 AM, Jay McCarthy wrote: >> >> On Fri, Apr 24, 2015 at 6:31 AM, George Neuner <gneun...@comcast.net> >> wrote: >> > On 4/23/2015 1:45 PM, Jay McCarthy wrote: >> > >> >> The values of the parameters are saved in the continuation and >> >> inherited from the thread. >> > >> > >> > That's going to be a problem because there's a large amount of state - >> > not >> > simply control variables, but also an open database connection and a >> > complex >> > dynamic database query that is expensive to re-execute. Many clients >> > may be >> > simultaneously executing separate instances of the query - if I can't >> > keep >> > the database connection open, I can't use per client temporary tables to >> > cache results and will have to do something ugly with a permanent table. >> > >> >> I'm surprised that you use so many parameters: >> >> http://docs.racket-lang.org/guide/parameterize.html?q=parameter#%28tech._parameter%29 > > > Why? Web applications are as complicated as native ones. > > There are 9 arguments to the initial request which are used to construct a > complex [expensive to execute] dynamic SQL query. This query may return > hundreds of results so the results need to be paged to the client. Also, > there is "exactly once" accounting that must be done on results that > actually are sent to the client [ not simply returned by the query ]. > > So it's not "parameterized" per se like a thread, but there is a lot of > state that needs to be maintained to service subsequent result page > requests: the open database connection [which maintains the query results > until closed], several pieces of client information used for accounting, the > current page of results, etc.
My point is that ONLY the result of make-parameter and parameterize is saved from the thread. In Racket a "parameter" has nothing to do with a function "argument". I believe you are confused by the two when you say "There are 9 arguments...". If you follow that documentation link, you'll see that "parameter" is a very specific thing in Racket and very few programs use them at all. Jay -- Jay McCarthy http://jeapostrophe.github.io "Wherefore, be not weary in well-doing, for ye are laying the foundation of a great work. And out of small things proceedeth that which is great." - D&C 64:33 -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
