SSD can be a huge deal for MySQL data warehouse deployments. Disk-bound joins between large tables can be slow because nested-loops join uses so many random reads. Hash join is one way to fix this. Decreasing the time for a random read is another.
Intel SSD can do a random read in less than 0.1 milliseconds. It also has great random write performance which has been an issue for SSD and the price is reasonable. Decreasing random read latency by 50X to 100X will make disk-bound joins much faster.
This should also help with:
- disk-bound aggregation when an indexed MyISAM temp table is used
- old-style external sort when the sort buffer contains (key, row pointer)