Hi Laing, I think you answered the wrong mail =). This one is around UV on custom range model.
But I am happy that you agree on my last message about the Datacenter switch. C*heers 2015-03-31 16:29 GMT+02:00 Laing, Michael <michael.la...@nytimes.com>: > We use Alain's solution as well to make major operational revisions. > > We have a "red team" and a "blue team in each AWS region, so we just add > and drop datacenters to get where we want to be. > > Pretty simple. > > ml > > On Tue, Mar 31, 2015 at 8:16 AM, Alain RODRIGUEZ <arodr...@gmail.com> > wrote: > >> People keep asking me if we finally found a solution (even if this is 3+ >> years old) so I will just update this thread with our findings. >> >> We finally achieved doing this thanks to our bigdata and reporting stacks >> by storing blobs corresponding to HLL (HyperLogLog) structures. HLL is an >> algorithm used by Google, twitter and many more to solve count-distinct >> problems. Structures built through this algorithm can be "summed" and give >> a good approximation of the UV number. >> >> Precision you will reach depends on the size of structure you chose >> (predictable precision). You can reach fairly acceptable approximation with >> small data structures. >> >> So we basically store a HLL per hour and just "sum" HLL for all the hours >> between 2 ranges (you can do it at day level or any other level depending >> on your needs). >> >> Hope this will help some of you, we finally had this (good) idea after >> more than 3 years. Actually we use HLL for a long time but the idea of >> storing HLL structures instead of counts allow us to request on custom >> ranges (at the price of more intelligence on the reporting stack that must >> read and smartly sum HLLs stored as blobs). We are happy with it since. >> >> C*heers, >> >> Alain >> >> 2012-01-19 22:21 GMT+01:00 Milind Parikh <milindpar...@gmail.com>: >> >>> You might want to look at the code in countandra.org; regardless of >>> whether you use it. It use a model of dynamic composite keys (although >>> static composite keys would have worked as well). For the actual query,only >>> one row is hit. This of course only works bc the data model is attuned for >>> the query. >>> >>> Regards >>> Milind >>> >>> /*********************** >>> sent from my android...please pardon occasional typos as I respond @ the >>> speed of thought >>> ************************/ >>> >>> On Jan 19, 2012 1:31 AM, "Alain RODRIGUEZ" <arodr...@gmail.com> wrote: >>> >>> Hi thanks for your answer but I don't want to add more layer on top of >>> Cassandra. I also have done all of my application without Countandra and I >>> would like to continue this way. >>> >>> Furthermore there is a Cassandra modeling problem that I would like to >>> solve, and not just hide. >>> >>> Alain >>> >>> >>> >>> 2012/1/18 Lucas de Souza Santos <lucas...@gmail.com> >>> > >>> > Why not http://www.countandra.org/ >>> > >>> > >>> > ... >>> >>> >> >
