Thanks Christian, that looks interesting. By the way, any idea what tool was used to generate the documentation?
On 23 February 2015 at 21:22, Christian Weilbach <whitesp...@polyc0l0r.net> wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > On 23.02.2015 18:20, Colin Yates wrote: >> Currently each request gets serviced in its own thread (web >> container) and I am thinking of integrating core.async and I wonder >> how core.async and a JDBC transactional "unit of work" get on. >> >> Conceptually, this model (thread-per-request) is trivial however >> the problems are well known. Replacing this with core.async right >> at the front is trivial but I can see the benefit of sprinkling >> asynchronous behaviour throughout the (still very trivial) >> pipeline. Or rather I can see the beauty of decomposed components >> communicating via channels. >> >> My question is about transactionality. I am used to JDBC >> transactions being thread local and I understand core.async >> utilises a thread-pool, so how does one implement a "unit of work" >> that spans multiple channels? >> >> I want to do something like: >> >> - request comes in - the appropriate handler/service consumes it >> (either through request mapping, defmethod whatever) - TX starts - >> in parallel some logging happens (and DB is updated) - the message >> is handled (and DB is updated) - performance metrics are stored >> (and DB is updated) - all work on all channels gets finished - TX >> commits >> >> The point is that channels are used only to communicate between >> disconnected components but they should all participate in the same >> TX. >> >> Is anyone else using channels like this? > I have done it in IndexedDB in JavaScript and had to use the proper > callback API (1), because otherwise transactions break. I guess you > cannot do channel operations inside a JDBC operation since they are > executed in the threadpool (by the state-machine) while each JDBC > connection seems to be pinned to a thread, so you cannot participate > in the same transaction from another thread of the threadpool. But if > you can wrap your blocking JDBC stuff in a singular thread call, you > might be able to use async/thread (probably less than you want). > > There is also https://github.com/niwibe/suricatta, but I have no > experience with it. jooq seems to solve the the thread per request > problem decoupling into async operations you have in mind. > > Cheers, > Christian > > (1) > https://github.com/ghubber/konserve/blob/master/src/cljs/konserve/indexeddb.cljs > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1 > > iQEcBAEBAgAGBQJU65n6AAoJEKel+aujRZMkwaAH/1Eq2/vr84WqNq6u2rcG4ly+ > xkByy602oMy9/ScK1/ytv/kFdPG+qAYmtQ4EHq/LGUma3zLjpPdrf49A1RUGfVii > fbwIUiRgUJWdigrGiSf/2zIn972MgIfc4qKFj/+/2hJNZIAwlAKiPQSvG2VPrHo7 > dskeQZeCZI4yGSz4+dQFGmKvjiAum+UConkzn0T/N2XGknerFsLonXyvpbTv/SCC > NwNoRJzI39kjIyhfUuwbwHoy0/DtbxjvkbrLHeyGIKGOJ75QutWY6gvkRsSlzS5g > A2jVtZo/hw02di3mxrD1vwSZ2PWads2juKjCmmOQrIPofSBWyVmoGeQ/qyD/Dgw= > =Wi7E > -----END PGP SIGNATURE----- > > -- > You received this message because you are subscribed to the Google > Groups "Clojure" group. > To post to this group, send email to clojure@googlegroups.com > Note that posts from new members are moderated - please be patient with your > first post. > To unsubscribe from this group, send email to > clojure+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/clojure?hl=en > --- > You received this message because you are subscribed to the Google Groups > "Clojure" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to clojure+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
