Increase table_cache and tmp_table_size
The Jamroom DataStore functions do their best to "force" MySQL to create as many tmp tables as it can in memory (i.e. my limiting all tables to no BLOB/TEXT columns and max length of 512 for VARCHAR columns), but sometimes no matter what you do MySQL is going to create a tmp table on disk (which is 100 times slower than creating it in RAM).
The good news is that DigitalOcean Droplets are all SSD (solid state disk) based - for random read/write access they are much faster than "normal" hard drives, and they really help with MySQL tmp table creation.
We are going to change both the table_cache and tmp_table_size values to somthing a little higher (the table_cache caches the table definition which speeds up the MySQL query planner while the tmp_table_size/max_heap_table_size settings define how much memory can be used for creating tmp tables):
I would recommend 64M for every 1 Gig of System RAM - so a 2 Gig Droplet would use 128M, a 4 Gig 256M and so on:
table_cache = 1536
tmp_table_size = 128M
max_heap_table_size = 128M
We also have set our table_cache up to 1536 which is a good number for the number of tables that Jamroom can have open at any given time.