Hidden dashboard variables can be stored as numbers or strings. I would like to be able to store arrays (such as DQL output) into a variable as well.
For instance, I have a dashboard with 21 tiles, each of which runs a query against a table, extracting the segment name and count for a single segment of the data. The query is essentially the same for all tiles, except for the filter to return different segments. The cost is high in time to run the queries and $'s as the table is very large even and the 3 hour window for the query encompasses 42Gb.
If I could retrieve data for all of the segments with a single DQL query by using Summarize By and store it in a hidden variable, this would save much time and money. The tiles could then each pull the count for their segment from the variable.