330 likes | 628 Views
. Make up day on Tuesday?Second mid-term?. Consistency Models Review. Enforcing absolute ordering is too expensive, especially with replication and caching.So we need to allow for mis-ordering".We could just do it casually. Tell programmers, Well, you always see things in exact order".They wou
E N D
1. Distributed Systems:Consistency Models CS 654Lecture 17November 13, 2006
2. Make up day on Tuesday?
Second mid-term?
3. Consistency Models Review Enforcing absolute ordering is too expensive, especially with replication and caching.
So we need to allow for mis-ordering.
We could just do it casually. Tell programmers, Well, you always see things in exact order.
They would say, What do you mean?
So we need an exact, very precise way of specifying the kinds of inconsistencies that the application might see.
That is the purpose and point of having consistency models.
4. Data Centric Consistency Models
5. Data Stores Consistency is viewed as read/write ops on shared data. A consistency model is a contract between the processes and the data store.