Re: [boost] NuDB: A fast key/value insert-only database for SSD drives in C++11

Subject: Re: [boost] NuDB: A fast key/value insert-only database for SSD drives in C++11
From: Gavin Lambert (gavinl_at_[hidden])
Date: 2017-03-22 04:13:31

On 22/03/2017 16:08, Vinnie Falco via Boost wrote:
> I think this can be unit tested, and I believe that NuDB's unit test
> covers the case of power loss. I think we can agree that power loss on
> a read is uninteresting (since it can't corrupt data). The unit test
> models a power loss as a fatal error during a write. The test
> exercises all possible fatal errors using an incremental approach (I
> alluded to this in my previous message).

A power loss is more like a fatal error that fails to execute any 
subsequent clean-up code, so it might not be quite the same.

There are also more pathological cases such as where a write has been 
partially successful and done some subset of increasing the file size, 
zeroing the extra file space, and writing some subset of the intended 
data.  So it's not necessarily that data is missing; there might be 
invalid data in its place.