Hi, On Tue, Nov 10, 2020 at 3:18 PM Durity, Sean R <sean_r_dur...@homedepot.com> wrote:
> My answer would depend on how many “names” you expect. If it is a > relatively small and constrained list (under a few hundred thousand), I > would start with something like: > At the moment, the number of names is more than 10,000 but not than 100,000. > > Create table last_values ( > > arbitrary_partition text, -- use an app name or something static to define > the partition > > name text, > > value text, > > last_upd_ts timestamp, > > primary key (arbitrary_partition, name); > What is the purpose of the partition key? (NOTE: every insert would just overwrite the last value. You only keep the > last one.) > This is the behavior that I want. :) > I’m assuming that your data arrives in time series order, so that it is > easy to just insert the last value into last_values. If you have to read > before write, that would be a Cassandra anti-pattern that needs a different > solution. (Based on how regular the data points are, I would look at > something time-series related with a short TTL.) > Okay, but as I know, this is the scenario when every update of the `last_values` generates two tombstones because of the update of the `value` and `last_upd_ts` field. Maybe I know it wrong? -- Bye, Auth Gábor (https://iotguru.cloud)
