On 10/10/14 21:10, Ewan Slater wrote:
what are the natural keys for your data (you may have a key with two or three components)?
I guess timestamp and "name" (eg temperature, humidity).
- how you are going to access the data (if you're always searching for time
stamp, it might make sense to include this in the key)?
What I'm going to need are: - Latest values (with their timestamps so I know how current they are) - All values in a date range (eg to draw a graph)
- whether the system that you're using supports indexing / value
extraction,or some other mechanism that avoids searching through the whole store to find a particular value ("full table scan").
That effectively brings me full circle to where I started, which is to be asking which system I should be using! I'd say I want something pretty flexible, although not as flexible as an RDBMS. The brief research I've done on memcached storage systems suggests that if I know the key I can get the value pretty much instantly, but I've not really found any thing that indicates how (or indeed if) I can search for keys matching some criteria, and how fast that would be. If, for example, it's possible to extract values for keys matching a regex then I could probably construct something pretty useful out of that.
Mark