4 ms·
There's still a difference between terabytes of data spread between RAM sticks multiple inches away from the CPU die and the megabytes of cache data close enoug
by tomatotomato37 4y ago
There's still a difference between terabytes of data spread between RAM sticks multiple inches away from the CPU die and the megabytes of cache data close enough to the compute silicon to experience quantum effects. A modern CPU can burn through hundreds of instructions in the time it takes to resolve a thrashing cache
- forrestthewoods 4y agoYes and? Latency (hand wavey) L1: 1 ns L2: 2.5 ns L3: 10 ns RAM: 50 ns SSD: 50,000 ns / 50 us Those are very approximate and specifics vary. RAM is 5 to 50 times more latent than cache. SSD is ~1000 times slower than RAM. And a spinning HDD is I think ~100 times slower than an SSD. If your database fits in RAM you’re likely in a happy place. If your DB is so massive it needs to spill to disk you wind up with a mountain of complexity. Multiple machines, sharding, hot/cold etc. The point of the article is “modern servers have a lot of RAM and you might be able to delete a lot of complexity if you throw money at a server with 4 terabytes of RAM. This option is more practical than you might have realized!”