Robert, I took a brief inspection at your code and seems very cool. Exactly what i was lloking for for my report generation and such.
I'm looking forward for more examples, but it seems a very valuable addition for our toolbox. Thanks a lot! On Wed, Oct 13, 2010 at 9:20 PM, Carles Gonzalez <carle...@gmail.com> wrote: > Neat! I'm going to see this code, hopefully I'll understand something :) > On Wednesday, October 13, 2010, Robert Kluin <robert.kl...@gmail.com> > wrote: > > Hey Dmitry, > > In case it might help, I pushed some code to bitbucket. At the > > moment I would (personally) say the code is not too pretty, but it > > works well. :) > > http://bitbucket.org/thebobert/slagg > > > > Sorry it does not really have good documentation at the moment, but > > I think the basic example I threw together will give you a good idea > > of how to use it. I need to do another cleanup pass over the API to > > make a few more refinements. > > > > I pulled this code out of one of my apps, and tried to quickly > > refactor it to be a bit more generic. We are currently using > > basically the same code in three apps to do some really complex > > calculations. As soon as I get time I will get an example up showing > > how to use it for neat stuff, like overall, yearly, monthly, and daily > > aggregates across multiple values (like total dollars and quantity). > > The cool thing is that you can do all of those aggregations across > > various groupings, like customer, company, contact, and sales-person, > > at once. I'll get that code pushed out in the next few days. > > > > Would love to get some feedback on it. > > > > > > Robert > > > > > > > > > > > > On Tue, Oct 12, 2010 at 17:26, Dmitry <dmitry.lukas...@gmail.com> wrote: > >> Ben, thanks for your code! I'm trying to understand all this stuff > >> too... > >> Robert, any success with your "library"? May be you've already done > >> all stuff we are trying to implement... > >> > >> p.s. where is Brett S.:) would like to hear his comments on this > >> > >> On Sep 21, 1:49 pm, Ben <pondneverfree...@yahoo.com> wrote: > >>> Thanks for your insights. I would love feedback on this implementation > >>> (Brett S. suggested we send in our code for this) > http://pastebin.com/3pUhFdk8 > >>> > >>> This implementation is for just one materialized view row at a time > >>> (e.g. a simple counter, no presence markers). Hopefully putting an ETA > >>> on the transactional task will relieve the write pressure, since > >>> usually it should be an old update with an out-of-date sequence number > >>> and be discarded (the update having already been completed in batch by > >>> the fork-join-queue). > >>> > >>> I'd love to generalize this to do more than one materialized view row > >>> but thought I'd get feedback first. > >>> > >>> Thanks, > >>> Ben > >>> > >>> On Sep 17, 7:30 am, Robert Kluin <robert.kl...@gmail.com> wrote: > >>> > >>> > Responses inline. > >>> > >>> > On Thu, Sep 16, 2010 at 17:32, Ben <pondneverfree...@yahoo.com> > wrote: > >>> > > I have a question about Brett Slatkin's talk at I/O 2010 on data > >>> > > pipelines. The question is about slide #67 of his pdf, > corresponding > >>> > > to minute 51:30 of his talk > >>> > > > http://code.google.com/events/io/2010/sessions/high-throughput-data-p... > >>> > >>> > > I am wondering what is supposed to happen in the transactional task > >>> > > (bullet point 2c). Would these updates to the materialized view > cause > >>> > > you to write too frequently to the entity group containing the > >>> > > materialized view? > >>> > >>> > I think there are really two different approaches you can use to > >>> > insert your work models. > >>> > 1) The work models get added to the original entity's group. So, > >>> > inside of the original transaction you do not write to the entity > >>> > group containing the materialized view -- so no contention on it. > >>> > Commit the transaction and proceed to step 3. > >>> > 2) You kick off a transactional task to insert the work model, or > >>> > fan-out more tasks to create work models :). Then you proceed to > >>> > step 3. > >>> > >>> > You can use method 1 if you have only a few aggregates. If you have > >>> > more aggregates use the second method. I have a "library" I am > almost > >>> > ready to open source that makes method 2 really easy, so you can have > >>> > lots of aggregates. I'll post to this group when I release it. > >>> > >>> > > And a related question, what happens if there is a failure just > after > >>> > > the transaction in bullet #2, but right before the named task gets > >>> > > inserted in bullet #3. In my current implementation I just left out > >>> > > the transactional task (bullet point 2c) but I think that causes me > to > >>> > > lose the eventual consistency. > >>> > >>> > Failure between steps 2 and 3 just means _that_ particular update > will > >>> > not try to kick-off, ie insert, the fan-in (aggregation) task. But > it > >>> > might have already been inserted by the previous update, or the next > >>> > update. However, if nothing else kicks of the fan-in task you will > >>> > need some periodic "cleanup" method to catch the update and kick of > >>> > the fan-in task. Depending on exactly how you implemented step 2 you > >>> > may not need a transactional task. > >>> > >>> > Robert > >>> > >>> > > Thanks! > >> > -- 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-appeng...@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.
