On App Engine, what does optimization for reads mean?
agreed with @redtuna (expecting more reads than writes) and @Ilian Iliev (reads cheaper than writes & writes take more resources). another way you can optimize for reads is by using the Memcache service. since reads (usually) happen more often than writes, caching that data means that you don't even have to take a hit of a datastore access. also, items that stay active (see fetches/hits) stay in the cache longer as it employs an LRU strategy.
In the documentation for Google App Engine, it says that when designing data models for the datastore, you should "optimize for reads, not writes". What exactly does this mean? What is more 'expensive', CPU intensive or time consuming?