nosql theory: All content tagged as nosql theory in NoSQL databases and polyglot persistence
Patrick Valduriez, co-author of the “Principles of Distributed Database Systems” book, has published a paper Principles of Distributed Data Management in 2020? (pdf) translating the main topic into the following 3 questions:
- What are the fundamental principles behind the emerging solutions?
- Is there any generic architectural model, to explain those principles?
- Do we need new foundations to look at data distribution?
Wrt (2), I showed that emerging solutions can still be explained along the three main dimensions of distributed data management (distribution, autonomy, heterogeneity), yet pushing the scales of the dimensions high up. However, I raised the question of how generic should distributed data management be, without hampering application-specific optimizations. Emerging NOSQL solutions tend to rely on a specific data model (e.g. Bigtable, MapReduce) with a simple set of operators easy to use from or with a programming language. It is also interesting to witness the development of algebras, with specific operators, to raise the level of abstraction in a way that enables optimization . What is missing to explain the principles of emerging solutions is one or more dimensions on generic/specific data model and data processing.
What I think this paper does is actually looking at two different questions, a bit less generic but still useful in proving that the new generation of distributed database systems was clearly triggered by the new requirements and the evolution of the current applications:
- Is there a need for new approaches in distributed data management systems?
- What are some of the approaches used by the emerging solution to deal with the challenges posed by today’s data-intensive applications?
You can read or download Patrick Valduriez’s paper here:
Download the slides, set aside 1 hour and 10 minutes of uncontended time, click the Maximize button, and watch this great presentation by Martin Thompson and Michael Barker diving into the Intel x86_64 processors and memory models for implementing lock-free algorithms. Once you’re done make sure to also read The Single Writer Principle by the same Martin Thompson.
Original title and link: Lock-Free Algorithms: How Intel X86_64 Processors and Their Memory Model Works ( ©myNoSQL)
A reminder to those thinking that networks never fail and automation can solve everything. Christina Ilvento, on behalf of the App Engine team:
The root cause of the outage was a combination of two factors during a scheduled network maintenance in one of our datacenters. As part of the scheduled maintenance, network capacity to and from this datacenter was reduced. This alone was expected, and was not a problem. However, this maintenance exposed a previously existing misconfiguration in the system that manages network bandwidth capacity.
Ordinarily, the bandwidth management system helps isolate and prioritize traffic. When capacity is reduced because of maintenance, network failure, or due to an excess of normal traffic, the bandwidth management system keeps things running smoothly by throttling back the rate of low priority traffic. However, as mentioned, the bandwidth management system had a latent misconfiguration which did not show up until capacity was reduced due to the scheduled maintenance. This misconfiguration under-reported the available network capacity to and from the datacenter, causing the network modeler to believe that there was less overall capacity than actually existed.
The configuration error in the bandwidth management system, when combined with an expected reduction in capacity due to the scheduled maintenance, led the system to conclude that there was insufficient bandwidth available for current traffic demand to and from this datacenter. (In reality, there was more than sufficient excess capacity, as otherwise the maintenance would not have been allowed to go forward.) Because of this combination of misconfiguration and scheduled maintenance, a number of services were automatically blocked from sending network traffic. […]
The outage occurred because two independent systems failed at the same time, which resulted in mistakes in our usual escalation procedures which significantly impacted the duration of the outage.
Original title and link: Networks Never Fail ( ©myNoSQL)
Scroll to minute 16:55 of this video to watch Jim Webber explain the benefits of polyglot persistence and how starting (again) the winner-takes-it-all war is just sending us back at least 10 years from the database Nirvana.
We’ve just come from the place where one-size-fits-all and we don’t want to go back there. There is a huge wonderful ecosystem of stores. Pick the right one. Don’t just assume that the one you find the easiest or the one that shouts the loudest is the one you’re going to use. Pick the one that suits your data model.
It doesn’t matter what flavor of relational or NoSQL database you prefer or have experience with or if a small or large database vendor is paying your bills. You really need to get this right as otherwise we’re just going to destroy a lot of valuable options we’ve added to our toolboxes.
Original title and link: The Database Nirvana ( ©myNoSQL)