AWS Certified Solutions Architect - Professional 2020

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Lazy writes – question on quiz has wrong answer

In the quiz it shows Lazy writes are an attribute of perpetual consistency. But explanation says "Lazy writes are typical of eventual consistency rather than perpetual consistency." Needs correction here.

Ryan O’Donnell

+1 good catch, lazy writes store data in the cache then write to the disk or memory at a later time making it eventual

5 Answers

I’ll put in a ticket.

I have brought it to Scott’s attention to review and adjudicate.

Cheers for the heads up. 
Moderator & Coach

Hi AK,

I thought I was wrong…but I was wrong.     The quiz question asked "Considering consistency models, which statements taken by themselves are incorrect?"   We are looking for the two answers that are INCORRECT.   So, the statement that "Lazy Writes are an attribute of perpetual consistency" is incorrect.  The explanation includes the statement that they are associated with eventual consistency.



I thought the same. It’s correctly incorrect 😀

I am quite confused with the term "perpetual consistency". Is this the whole point of this choice, that there is no established term of "perpetual consistency" and thus it is incorrect? I have not come across the term "Perpetual consistency" before on my career and could not find any reference to such thing, but the quiz explanation (and this discussion) talks about it like it is something that we should know of.

Correct me if I’m wrong, but I think the explanation could still be improved by stating that it is a bogus term, or that it should simply state strong consistency.


i would also love this to be answered, what is the point here?

"Perpetual consistency" sounds like atomicity or relational transactional data system like MS SQL / RDS. Glad other people found the term strange b/c it is confusing me too.


I’ve worked with database for decades and I’ve never heard of that term. I readily admit I don’t know everything though. But this was the first time I’ve seen these term. I guess the counterpart would be "eventual consistency"? So, persistence is either "eventual" or "immediate". Not sure how "perpetual" fits in.

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