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There is a diagram of a process that reads the MySQL commit log and uses that to send Memcache delete commands. Not exactly groundbreaking. But I would also gu
by thephyber 3y ago
There is a diagram of a process that reads the MySQL commit log and uses that to send Memcache delete commands. Not exactly groundbreaking.
But I would also guess that FB would have to explain lots of their middleware concepts in order to explain how data in the database maps to memcache keys defined in middleware.
Personally, I think the hard part is ensuring the entire company/system accesses data through the correct abstractions (eg. the newest data model code) and does not bypass the data model code (eg. by hitting the database directly).
- bagels 3y agoThere are a few layers above this as well as safeguards to help make sure the right abstractions are used.
- YZF 3y agoSo the cache can be out of sync with the database before that log processing gets done with deleting?
- AlphaCharlie 3y agoThe binlogs are applied first, then the deletes are emitted. There’s also support for read after write consistency within a single cluster by adding a canary to the memcache key warning to read from the master replica after the write succeeds, that’s a really cool feature for a multi region eventually consistent system