The difference between blocking disk I/O and other sources of conn thread 'blocking' is that the I/O problem can be solved with a small number of light weight threads which take the blocking on the chin for you, but there's not much you can do about arbitrary script processing.
I don't think the read-the-whole-file-in-the-conn-thread solution scales very well when faced with a directory of CD images or a distribution of Debian packages :-) Dragging this back to the topic at hand, what this highlights to me is that infrastructure can be tricky, so you don't want to be re-implementing it ad-hoc. The Ns_ParseProc interface allows new protocol implementations to take full advantage of AOLserver's cool infrastructure, transparently. Cheers. On Thu, 2004-08-19 at 06:14, Jim Wilcoxson wrote: > I guess I was unclear in my earlier note: > > 1. The HTTP driver thread reads all input for request, w/o blocking. > My understanding is that this is now happening in AS 4 - great! > > 2. A conn service thread creates the output, either by running a TCL > script, executing fastpath to read a file into memory, etc. This > might do stats, file I/O, database I/O, etc., and may block. The > result of this thread is a memory buffer. > > 3. The HTTP driver thread spools the memory buffer back to the client, > w/o blocking. > > I wasn't suggesting that there should be no blocking in step 2, when > the output is being created. That's why multiple connection service > threads are needed. But the problem of a connection service thread > being tied up while it spools a large page/image is eliminated. > > In the application of an image server, it would be nice if there could > be one fastpath thread that did all non-blocking filesystem I/O > (actually just reading is needed), or an asynchronous sendfile, but I > agree with you that there are not good portable ways to do that yet. > > Jim > ge. You can leave the Subject: field of your email blank. -- AOLserver - http://www.aolserver.com/ To Remove yourself from this list, simply send an email to <[EMAIL PROTECTED]> with the body of "SIGNOFF AOLSERVER" in the email message. You can leave the Subject: field of your email blank.
