Hi Chathura, Please see my comments in line.
On Mon, Apr 4, 2016 at 10:39 AM, Chathura Ekanayake <[email protected]> wrote: > Hi Geeth, > > Nice work. Few points.. > > 1) When joining search criteria, is it possible to enforce order of join > operators using parentheses? E.g. (cpu usage > 30% or battery level < 10%) > and location = colombo > This in not available in current implementation, It is a nice improvement to add. We will surely consider this in our road map. > > 2) When the retrieval task writes data to tables, does it overwrite > existing rows or insert a new row (with a timestamp)? I think it can be > useful to keep past data in order to facilitate analysis. If we are storing > each data item collected periodically, DAS can be a better place to store > and analyze them. > We don't update the existing table, When new data arrives for a certain device, we delete existing data and insert them as a new record. There are reasons to do that, 1. EMM/IoT server only keep the snapshot of the device meta data. If someone searches the devices, he always wants to know the current status of the device, 2. We are implementing mechanism to pump all the data to DAS from the retrieval task and also from other operations. So only DAS will keep past data, which we will use for generating reports. If someone wants to look at historical analysis, they have to use DAS. 3 Reason for deleting and inserting is updating a record is an expensive operation AFAIK, because it will lock the DB table. Thanks for the valuable feedback. Thanks Geeth > > Regards, > Chathura >
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