Hello there.
It looks like the db engine when a new data-partition table is created creates the primary key clustered index on time and tagid, and also created a non-clustered index on timestamp.
These non-clustered indexes take up quite a bit of room since there are so many unique timestamps for each data partition. I have done a little experimentation with removing the timestmap index on a table and running a handful of queries, and the query times don't seem to change much, if at all. I'm not a database guru but, since I do understand that since the data is already sorted by tagid and timestamp, the non-clusted index seems a little redundant, and also leads to the database getting larger a lot faster (for my table it halved the table size after I removed it).
Anyways, just curious to see if anyone else has gone down this road and experimented with these indexes as well, in hopes of getting their DB bill down a bit while not sacrificing performance.
Thanks!