Hi, I'm the original author of this article, though I have since left Pinterest.
180M/s is the peak throughput I've observed from the entire fleet, and is an accurate figure.
It's worth noting that:
(1) When it comes to caching workloads, there is often a wide spread of request amplification factor from a single inbound user request to the site. For example, a search query on Pinterest might internally fan out to an order of magnitude more requests to memcached across several different services along the request path used for servicing that query.
(2) There are many systems outside of the online critical path that use caching, which add load on the system independent of the rate at which users are posting or viewing content on the Pinterest site.
As another reference point, Facebook, who developed mcrouter, shared that their memcached deployment serves on the order of billions of requests per second [0]. And this figure is from 2014; I imagine it's grown a lot since then.
Google serves up way way more than 63k queries per second (several million requests/s is common for the critical services around search). Source: I worked there.
However, your main point is valid (180 million/s seems way too high). I've started a thread internally to double check these numbers. Please wait for an update.
> Google serves up way way more than 63k queries per second (several million requests/s is common for the critical services around search). Source: I worked there.
Yeah, 36k per instance (especially on an xlarge or 2xlarge EC2 instance) is well within the serving capacity of memcached. While it depends a lot on the workload profile for a specific cluster, some clusters serve on the order of ~5k/instance while others are as high as ~100k/instance. We've done a lot of experimentation with extstore as well; it certainly eats up more compute cycles on average than an equivalent in-memory only cluster, but is still quite efficient.
180M/s is the peak throughput I've observed from the entire fleet, and is an accurate figure.
It's worth noting that:
(1) When it comes to caching workloads, there is often a wide spread of request amplification factor from a single inbound user request to the site. For example, a search query on Pinterest might internally fan out to an order of magnitude more requests to memcached across several different services along the request path used for servicing that query.
(2) There are many systems outside of the online critical path that use caching, which add load on the system independent of the rate at which users are posting or viewing content on the Pinterest site.
As another reference point, Facebook, who developed mcrouter, shared that their memcached deployment serves on the order of billions of requests per second [0]. And this figure is from 2014; I imagine it's grown a lot since then.
[0] https://www.usenix.org/system/files/conference/nsdi13/nsdi13...