Re:Fast key-value stores: An idea whose time has come and gone
by inlined on Monday June 24, 2019 @10:32AM
(#20263874)
For me the most important part was in the abstract: autoscaling. It’s not just about going to zero but going to hundreds of thousands. I can remember my two most painful times with memcache:
1. A client scaled rapidly & we had repeated hits on the same key. We were saturating the NIC in the memcache server. We had to addd indirection for some data and introduced an local in-memory layer in front of memcache.
2. We had to extend the ring size to give memcache better CPU utilization. We had to teach all our code to handle a migration process (reads were fall through to the new ring and writes purged both). We couldn’t just turn off memcache because a total dump would overwhelm the database.
1. A client scaled rapidly & we had repeated hits on the same key. We were saturating the NIC in the memcache server. We had to addd indirection for some data and introduced an local in-memory layer in front of memcache.
2. We had to extend the ring size to give memcache better CPU utilization. We had to teach all our code to handle a migration process (reads were fall through to the new ring and writes purged both). We couldn’t just turn off memcache because a total dump would overwhelm the database.