Write-through cache
A caching policy in which every write goes to the cache and the database together, so the cache always holds the latest value for the keys written through it. Reads hit more often and are never stale for those keys, but each write is slower and the cache fills with data that may never be read. Cache-aside and write-behind are the common alternatives.
Data
In Quorum#
Write-through is designed as a Cache strategy but not in the game yet. Today a Cache works like cache-aside with invalidation: writes pass through to the Database and invalidate keys, so its hit ratio falls by twice the write share, at most by half. Between invalidations some hits are stale, from 0.5% to 10% per unit of write share as the TTL grows from 10 s to 1 hour.
Read next#
Cache-aside, Cache hit rate, Eventual consistency, Cache stampede