When a distributed system has mutable data, nodes need to know which is the most recent value, so a versioned value stores a version number with every value.
more… https://martinfowler.com/articles/patterns-of-distributed-systems/versioned-value.html
Unmesh Joshi is completing another batch of his series on Patterns of Distributed Systems. First of these is Gossip Dissemination, which uses a random selection of nodes to pass on information to ensure it reaches all the nodes in the cluster without flooding the network
more… https://martinfowler.com/articles/patterns-of-distributed-systems/gossip-dissemination.html
There are arguments about whether a testing portfolio should be a pyramid or more like honeycomb. My second biggest issue with this argument is that it's rendered opaque by the fact that it's not clear what people see as the difference between unit and integration tests. more… https://martinfowler.com/articles/2021-test-shapes.html
Recently there's been a lot of interest, indeed hype, around building developer productivity platforms. Done well, they make it easier for developers to build systems aligned with the technology strategy and allow them to build useful features more quickly. However many organizations struggle because in order to do a good job of platforms, you need to have a number of baseline capabilities in place first. That way the platform can be designed and operated a
It's often necessary to access the historical values of some property. But sometimes this history itself needs to be modified in response to retroactive updates. Bitemporal history treats time as two dimensions: actual history records what history should be given perfect transmission of information, while record history captures how our knowledge of history changes.
more… https://martinfowler.com/articles/bitemporal-history.html
Pull Requests are a mechanism popularized by github, used to help facilitate merging of work, particularly in the context of open-source projects. A contributor works on their contribution in a fork (clone) of the central repository. Once their contribution is finished they create a pull request to notify the owner of the central repository that their work is ready to be merged into the mainline. Tooling supports and encourages code review of the contribution before accepting the re
When people think of code reviews, they usually think in terms of an explicit step in a development team's workflow. These days the Pre-Integration Review, carried out on a Pull Request is the most common mechanism for a code review, to the point that many people witlessly consider that not using pull requests removes all opportunities for doing code review. Such a narrow view of code reviews doesn't just ignore a host of explicit mechanisms for review, it more importantly neglects pr
Clients send requests to servers but might not get a response. It's impossible for clients to know if the response was lost or the server crashed before processing the request. To make sure that the request is processed, the client has to re-send the request.
If the server had already processed the request and crashed after that,
servers will get duplicate requests when the client retries.more… https://martinfowler.com/articles/patterns-of-distributed-systems/
Tim finishes his article by looking at how highly effective organizations design their engineering organization to optimize for effectiveness and feedback loops. He illustrates what this looks like by the example of Etsy, who actively measures their ability to put valuable products into production quickly and safely, adjusting their technical investments to fix any blockers or slowness.
more… https://martinfowler.com/articles/developer-effectiveness.html#Organiz
Clients are interested in changes to the specific values on the server. It's difficult for clients to structure their logic if they need to poll the server continuously to look for changes. If clients open too many connections to the server for watching changes, it can overwhelm the server.
more… https://martinfowler.com/articles/patterns-of-distributed-systems/state-watch.html