Software Engineering Radio

Eric Olden talks with host Giovanni Asproni about identity orchestration, a software approach for managing distributed identity and access management (IAM) and integrating multiple identity systems or providers (IDPs) to make them look like a single system from a user perspective. The episode starts with a refresher in identity and access management, then introduces identity orchestration and some of the challenges it helps to address, such as integrating disparate identity management systems after company mergers or acquisitions; managing identities in situations where some of the IAM systems are unreachable; and implementing more secure identity management in legacy applications. Brought to you by IEEE Computer Society and IEEE Software magazine.

Jaxon Repp of HarperDB speaks with Brijesh Ammanath about distributed data infrastructure, including what it is and why it's important. They discuss the key factors that make distributed data infrastructure attractive, as well as challenges to implementing it. The episode explores the architecture and design principles, the key security considerations, and the transition factors for distributed data Infrastructure. Brought to you by IEEE Computer Society and IEEE Software.

Yeckezkel Rabinovich , CTO of Groundcover, speaks with host Philip Winston about observability and eBPF as it applies to Kubernetes. Rabinovich was previously the chief architect at the healthcare security company CyberMDX and spent eight years in the cyber security division of the Israeli Prime Minister’s Office. This episode explores the three pillars of observability, extending the Linux Kernel with eBPF, the basics of Kubernetes, and how Groundcover uses eBPF as the basis for its observability platform.

Andy Suderman , CTO of Fairwinds, joins host Robert Blumen to talk about standing up a kubernetes cluster. Their discussion covers build-your-own versus managed clusters provided by cloud services, and how to determine the number of kubernetes clusters an organization needs. Andy describes best practices for automating cluster provisioning, and offers recommendations about customizations and opinionation of cloud service providers, choice of container registry, and whether you should run complementary services such as CI and monitoring on the same cluster. The episode also examines the day 0/day 1/day 2 lifecycle, cluster auto-scaling at the cloud service level, integrating stateful services and other cloud services into your cluster, and kubernetes secrets and alternatives. Finally, they consider the container-network interface (CNI), ingress and load balancers, and provisioning external DNS and TLS certificates for cluster services.

Zac Hatfield-Dodds , the Assurance Team Lead at Anthropic, speaks with host Gregory M. Kapfhammer about property-based testing techniques and how to use them in an open-source tool called Hypothesis. They discuss how to define properties for a Python function and implement a test case in Hypothesis. They also explore some of the advanced features in Hypothesis that can automatically generate a test case and perform fuzzing campaigns.

José Valim , creator of the Elixir programming language, Chief Adoption Officer at Dashbit, and author of three programming books, speaks with SE Radio host Gavin Henry about what Elixir is today, what Livebook is, the five spearheads of the new machine learning ecosystem for Elixir, and how they all fit together. Valim describes why he created Elixir, what “the beam” is, and how he pitches it to new users. This episode examines things you can do with Livebook and how it is well-aligned with machine learning, as well as why immutability is important and how it works. They take a detailed look at a range of topics, including tensors with Nx, traditional machine learning with Scholar, data munging with Explorer, deep learning and neural networks with Axon, Bumblebee and Huggingface, and model creation basics. Brought to you by IEEE Computer Society and IEEE Software magazine.

M. Scott Ford , the CTO of Corgibytes and host of the Legacy Code Rocks podcast, discusses managing dependency freshness. SE Radio’s Sam Taggart speaks with him about why dependency freshness is important to ensure that your code has all the latest bug fixes, how exactly to measure dependency freshness, and some of the insights that teams can gain from monitoring freshness over time. Brought to you by IEEE Computer Society and IEEE Software Magazine.

Nikhil Shetty , an expert in networking and distributed systems, speaks with SE radio's Kanchan Shringi about virtual private cloud (VPC) and related technologies. They explore how VPC relates to public cloud, private cloud, and virtual private networks (VPNs). The discussion delves into why VPC is fundamental to building on the cloud, as well as configuring a VPC, subnets, and the address space that can be assigned to the VPC. During this episode they look into route tables, network address translation, as well as security groups, network access control lists, and DNS. Finally, Nikhil helps compare VPC offerings from Amazon Web Services (AWS) and Oracle Cloud Infrastructure (OCI).

Adam Frank , SVP of Product and Marketing at Armory.io, speaks with SE Radio’s Kanchan Shringi about continuous integration, continuous delivery, and continuous deployment – and how they differ. Frank suggests that organizations begin by identifying how the CI/CD process aligns best with their unique goals, noting that such goals might be different for B2C versus B2B SAAS (software as a service). They also discuss how the process can differ for monoliths compared to microservices-based products. Finally, they talk about continuous deployment as a service and some unique aspects of Armory’s approach.

Charles Weir —developer, security researcher, and Research Fellow at Security Lancaster—joins host Giovanni Asproni to discuss an approach that development teams can use to create secure systems without wasting effort on unnecessary security work. The episode starts with a broad description of the approach, which is based on Weir's research and on a free Developer Security Essentials workshop he created. Charles presents some examples from real-world projects, his view on AI's impact on security, and information about the workshop and where to find the materials. During the conversation, they consider several related topics including the concept of "good enough" security; security as a product decision; risk assessment, classification, and prioritization; and how to approach security in startups, greenfield, and legacy systems.

Dr. Daniel Zingaro and Dr. Leo Porter , co-authors of the book Learn AI-Assisted Python Programming, speak with host Jeremy Jung about teaching programming with the aid of large language models (LLMs). They discuss writing a book to use in Leo's introductory CS class and explore how GitHub Copilot de-emphasizes syntax errors, reduces the need to memorize APIs, and why they want students to write manual test cases. They also discuss possible ethical concerns of relying on commercial tools, their impact on coursework, and why they aren't worried about students cheating with LLMs.

Zach Lloyd , CEO of Warp.dev, discusses how to implement and effectively use command-line terminals. Host Gregory Kapfhammer speaks with Lloyd about how command-line terminals work and how the Warp terminal uses the GPU and AI to enhance a software developer’s productivity. They also discuss the trade-offs associated with using the Rust programming language to implement a command-line terminal. Brought to you by IEEE Computer Society and IEEE Software magazine.

Josh Doody , author of Mastering Business Email, speaks with host Brijesh Ammanath about how software engineers can master business communication. They begin with an exploration of various communication modes, including Slack, virtual meetings, emails, and presentations. Josh shares several strategies to improve communication skills and cross-cultural communication, but if there's one key take away from this episode, it might be: “use positive language for any medium of communication; be kind and use positive words.” Brought to you by IEEE Software magazine and IEEE Computer Society.

Arun Gupta , Vice President and General Manager of Open Ecosystem Initiatives at Intel Corporation, discusses open-source strategy and community with SE Radio host Kanchan Shringi . They explore the business case and business model for why and how big tech participates in the open-source ecosystem. Arun describes ways to foster a culture of engagement with open source within companies such as Intel, Amazon, and Apple. They then consider how the principles can be applied to closed-source software within a company. Finally, they discuss some of the benefits that Intel has gained from more than 20 years of open source contributions and look at the company’s plan for the year ahead. SE Radio is rought to you by IEEE Software magazine and IEEE Computer Society.

In this episode, Ori Mankali , senior VP of engineering at cloud security startup Akeyless, speaks with SE Radio’s Nikhil Krishna about secrets management and the innovative use of distributed fragment cryptography (DFC). In the context of enterprise IT, 'secrets’ are crucial for authentication in providing access to internal applications and services. Ori describes the unique challenges of managing these sensitive data, particularly given the complexities of doing so on a large scale in substantial organizations. They discuss the necessity for a secure system for managing secrets, highlighting key features such as access policies, audit capabilities, and visualization tools. Ori introduces the concept of distributed fragment cryptography, which boosts security by ensuring that the entire secret is never known to any single entity. The episode explores encryption and decryption and the importance of key rotation, as they consider the challenges and potential solutions in secrets management.

Casey Muratori caused some strong reactions with a blog post and an associated video in which he went through an example from the “Clean Code” book by Robert Martin to demonstrate the negative impact that clean code practices can have on performance. In this episode, he joins SE Radio’s Giovanni Asproni to talk about the potential trade-offs between performance and the qualities that make for maintainable code, these qualities being the main focus of Clean Code. Brought to you by IEEE Computer Society and IEEE Software magazine.

Jens Neuse , founder of Wundergraph, joins SE Radio host Jeff Doolittle for a conversation about back ends for front ends, or BFF. Jens begins by explaining how a heavy integration burden is often placed on front-end development teams. When multiple APIs must be integrated, it can be challenging for client development in web, mobile, and desktop environments. Explaining how APIs should be treated as dependencies, just like packages, the episode explores BFF patterns and use cases, as well as the future potential emergence of a “git for APIs” standard. This episode is sponsored by ClickSend .

Nir Valtman , co-Founder and CEO at Arnica, discusses pipelineless security with SE Radio host Priyanka Raghavan . They start by defining pipelines and then consider how to add security. Nir lays out the key challenges in getting good code coverage with the pipeline-based approach, and then describes how to implement a pipelineless approach and the advantages it offers. Priyanka quizzes him on the concept of "zero new hardcoded secrets," as well as some ways to protect GitHub repositories, and Nir shares examples of how a pipelineless approach could help in these scenarios. They then discuss false positives and handling developer fatigue in dealing with alerts. The show ends with some discussion around the product that Arnica offers and how it implements the pipelineless methodology.

Chad Michel , Senior Software Architect at Don’t Panic Labs and co-author of Lean Software Systems Engineering for Developers , joins host Jeff Doolittle for a conversation about treating software development as an engineering discipline. They begin by discussing the need for engineering rigor in the software industry. Chad points out that many developers lack awareness of good engineering practice and are often unaware of resources such as the Software Engineering Body of Knowledge (SWEBOK). Among the many topics explored in this episode are design methodologies such as volatility-based decomposition and the work of David Parnas, as well as important topics such as quality, how to address complexity, designing for change, and the role of the chief engineer. This episode is sponsored by ClickSend . SE Radio listeners can get a $50 credit by following the link.

In this episode, Varun Singh , Chief Products and Technology Officer at Daily.co , speaks with host Nikhil Krishna about the 30-year evolution of web protocols. In particular, they explore the impact of protocol ossification, which has supported the Internet’s success but also limits the flexibility of evolving protocol suites such as TCP/IP and UDP by constraining future development. Varun points out how the end-to-end principle emphasizes full flexibility for end hosts, but the TCP implementation in the OS kernel as well as in “middle boxes” such as ISPs contributes to the constraints of ossification by blocking certain types of traffic. Further, the development of new protocols is challenging due to the need for backward compatibility with existing protocols. They discuss Google’s efforts – and the challenges it has faced – in working to move the HTTP protocol forward. The role of standards bodies such as the IETF and collaboration between industry stakeholders is crucial for the evolution of internet protocols, requiring a balance between maintaining backward compatibility and introducing new protocols such as QUIC and HTTP/3 to address existing constraints and improve internet performance and security. indeed, QUIC includes features that seek to actively avoid ossification and encourage evolution.

Gregory Kapfhammer , associate professor at Allegheny College, discusses the common problem of ‘flaky tests’ with SE Radio’s Nikhil Krishna . Flaky tests are test cases that unreliably pass or fail even when no changes are made to the source code under test or to the test suite itself, which means that developers can’t tell whether the failures indicate bugs that needs to be resolved. Flaky tests can hinder continuous integration and continuous development by undermining trust in the CI/CD environment. This episode examines sources of flaky tests, including physical factors such as CPU or memory changes, as well as program-related factors such as performance issues. Gregory also describes some common areas that are prone to flaky tests and ways to detect them. They discuss tooling to detect and automatically mark flaky tests, as well as how to tackle these issues to make tests more reliable and even ways to write code so that it's less susceptible to flaky tests.

Jeroen Mulder , author of Multi-Cloud Strategy for Cloud Architects , joins host Robert Blumen for a discussion of public cloud, private cloud, and multi-cloud computing architectures and trends. They start by considering what defines cloud computing and what differentiates the major cloud providers, including whether they are more alike or different in the services they offer. Jeroen discusses governance, regulatory compliance, and data locality as drivers of where enterprises want to run their workload. They explore use cases for multi-cloud, and discuss architectural challenges in migrating to kubernetes, as well as issues with networking, security, and identity management with multi-cloud architectures. Finally, they discuss running public cloud compute on on-prem resources with Anthos, Outback, and related technologies.

Stanisław Barzowski of XTX Markets and a committer on the jsonnet project joins SE Radio's Robert Blumen for a conversation about the jsonnet programming language. A superset of JSON, jsonnet adds programming language capabilities, particularly to address the need to handle large but mostly repetitive JSON configurations. They discuss the project’s history, use cases for Grafana and Kubernetes config, and interoperability with YAML. They examine jsonnet details, including the command line, constrained capabilities of the language, and objects and inheritance, and then consider the toolchain: compiler, formatter, and linter, as well as test frameworks and testing, package management, and the language’s performance. Barzowski describes four implementations -- go, C++, Rust, and Scala -- as well as popular libraries and the standard library.

Vladyslav Ukis , author of the book Establishing SRE Foundations: A Step-by-Step Guide to Introducing Site Reliability Engineering in Software Delivery Organizations , discusses how to roll out SRE in an enterprise. SE Radio host Brijesh Ammanath speaks with Vlad about the origins of SRE and how it complements ITIL (Information Technology Infrastructure Library). They examine how firms can establish foundations for rolling out SRE, as well as how to overcome challenges they might face in adopting. Vlad also recommends steps that organizations can take to sustain and advance their SRE transformation beyond the foundations.

Simon Bennetts , a distinguished engineer at Jit, discusses one of the flagship projects of OWASP: the Zed Attack Proxy (ZAP) open source security testing tool. As ZAP’s primary maintainer, Simon traces the tool's origins and shares some anecdotes with SE Radio host Priyanka Raghavan on why there was a need for it. They take a deep dive into ZAP’s features and its ability to integrate with CI/CD, as well as shift security left. Bennetts also considers what it takes to build a successful open source project before spending time on ZAP’s ability to script to provide richer results. Finally, the conversation ends with some questions on ZAP’s future in this AI-powered world of bots.

Dave Cross , owner of Magnum Solutions and author of GitHub Actions Essentials (Clapham Technical Press), speaks with SE Radio host Gavin Henry about GitHub actions, the value they provide, and the best practices for using them in your projects. Cross describes the vast range of things that developers can do with GitHub Actions, including some use cases you might never have thought about. They start with some general discussion of CI/CD and then consider the three main types of events that drive GitHub actions before digging in to details about fine-grained action events, Action Marketplace, contexts, yaml, docker base images, self-hosted runners, and more. They further explore identity management, permissions, dependency management, saving money, and how to keep your secrets secret.

Ashley Peacock , author of the book Creating Software with Modern Diagramming Techniques , speaks with SE Radio host Akshay Manchale about diagrams in software engineering. They discuss the power of diagramming and some reasons we don’t fully use it as often as we should. Ashley contrasts historical use of UML diagrams versus modern diagrams, which don't have hard rules about representations. The episode examines different types of diagrams through an example application and how it could be built with modern tools such as Streamy to simplify the building, versioning, and maintenance of diagrams.

Luca Galante , head of product at Humanitec, joins host Jeff Doolittle for a conversation about platform engineering. They begin by defining platform engineering and its relationship to, and distinction from, DevOps. Tracing platform engineering's history, Luca describes how internal developer platforms are fundamental, and then explores the goals of addressing complexity and reducing the cognitive load on developers by creating golden paths.

Paul Hammant , independent consultant, joins host Giovanni Asproni to speak about trunk-based development—a version control management practice in which developers merge small, frequent updates to a core “trunk” or main branch. The episode explores the technique in some detail, including its pros and cons and some examples from real projects, and offers suggestions on how to get started. The conversation touches on a set of related topics, including code reviews, feature flags, continuous integration, and testing.

In this episode, David Cramer , co-founder and CTO of Sentry, joins host Jeremy Jung for a conversation about error tracking. The discussion starts with treating performance problems as errors, why you might not need logs, and how most applications share the same problems. From there they consider other topics including capturing information by hooking into runtimes and frameworks, issues with the quality of Open Telemetry data, how front-end applications are constantly changing and why that makes them hard to instrument. Finally, they discuss how Sentry's architecture has evolved, and why they switched from a permissive license to the Business Source License.

Bastian Gruber , author of the book Rust Web Development , speaks with host Philip Winston about creating server-based web applications with Rust. They explore Rust language features, tooling, and web frameworks such as Warp and Tokio. From there, they examine the steps to build a simple web server and a RESTful API, as well as modules, logging and tracing, and other aspects of web development with Rust.

Dan DeMers of Cinchy.com joins host Jeff Doolittle for a conversation about data collaboration and dataware. Dataware platforms leverage an operational data fabric to liberate data from apps and other silos and connect it together in real-time data networks. They explore a range of key topics, including zero-copy integration, encapsulation and information hiding, handling changes to data models over time, and latency and access issues. The discussion also explores dataware management and security concerns, as well as the concept of 'data plasticity' as an analogy to neuroplasticity, which is where the nervous system can respond to stimuli such as injuries by reorganizing its structure, functions, or connections.

Sugu Sougoumarane discusses how to face the challenges of horizontally scaling MySQL databases through the Vitess distribution engine and Planetscale, a service built on top of Vitess. The journey began with the growing pains of scale at YouTube around the time of Google’s acquisition of the video service. This episode explores ideas about topology management, sharding, Paxos, connection pooling, and how Vitess handles large transactions while abstracting complexity from the application layer.

Ross John Anderson, Professor of Security Engineering at University of Cambridge, discusses software obsolescence with host Priyanka Raghavan . They examine risks associated with software going obsolete and consider several examples of software obsolescence, including how it can affect cars. Prof. Anderson discusses policy and research in the area of obsolescence and suggests some ways to mitigate the risks, with special emphasis on software bills of materials. He describes future directions, including software policy and laws in the EU, and offers advice for software maintainers to hedge against risks of obsolescence.

Michael Fazio , Engineering Manager (Android) at Albert and author of Kotlin and Android Development featuring Jetpack from the Pragmatic Programmers, speaks with SE Radio's Gavin Henry about how the Android ecosystem looks today, and why it's an excellent time to write native Android apps. They explore a wide range of topics about modern Android development, including when to go native, how to keep a lot of decisions in your back-end API, Kotlin co-routines, Jetpack and Jetpack Compose, the MVVM design pattern, and threads, as well as activities, fragments, Dagger, room, navigation, Flutter, and improvements in simulators. They also examine details such as IDEs, API selection, how to choose a list of support devices, Java vs Kotlin, handset manufacturers, XML layouts, and why Jetpack is a safe bet for all your future Android development.

Software engineer Alex Boten , author of Cloud Native Observability with Open Telemetry, joins SE Radio host Robert Blumen for a conversation about software telemetry and the OpenTelemetry project. After a brief review of the topic and the OpenTelemetry project's origins rooted in the need for interoperability between telemetry sources and back ends, they discuss the open telemetry server and its features, including transforms, filtering, sampling, and rate limiting. They consider a range of topics, starting with alternative topologies with and without the telemetry server, server pipelines, and scaling out the server, as well as a detailed look at extension points and extensions; authentication; adoption; and migration.

On Freund , founder of Wilco and former VP of Engineering at WeWork, speaks with SE Radio’s Brijesh Ammanath about “upskilling” – going deeper or increasing the breadth of your skills . On has years of experience in helping developers master the skills needed to advance in their careers. This episode explores the importance of upskilling in a constantly evolving tech landscape. They focus particularly on how and why senior and expert developers should keep learning, upskilling, and reskilling throughout their careers. Freund offers suggestions on how to face some common challenges, especially for remote or distributed workers, and how and why engineering managers can help enable upskilling for their teams.

Adam Tornhill , founder and CTO of CodeScene, joins host Giovanni Asproni to speak about behavioral code analysis. Behavioral code analysis is a set of practical techniques aimed at identifying patterns in how a development organization interacts with the codebase they're building. It can be used to prioritize technical debt to maximize return on investment; to identify communication and team-coordination bottlenecks in code; to drive refactorings guided by data from how the system evolves; and to detect code quality problems before they become maintenance issues. The episode starts with a broad description of the techniques, providing some examples from real projects, and ends with suggestions on how to get started with applying them. During the conversation, Adam and Giovanni touch on a set of related topics, including the applicability of the techniques to legacy, green-, and brown-field projects; ethical and privacy implications; and the importance of context when judging code quality.

Luca Casonato joins SE Radio's Jeremy Jung for a conversation about Deno and Deno Deploy. They start with a look at JavaScript runtimes and their relation to Google’s open source JavaScript and WebAssembly engine V8, and why Deno was created. They discuss the WinterCG W3C group for server-side JavaScript, why it's difficult to ship new features in Node, and the benefits of web standards. From there they consider the benefits of creating an all-inclusive toolset like Rust and Go rather than relying on separate solutions, Deno's node compatibility layer, use cases for WebAssembly, benefits and implementation of Deno Deploy, reasons to deploy on the edge, and what's coming next.

Matt Frisbie , author of Building Browser Extensions , speaks with host Kanchan Shringi about browser extensions, including key areas where they've been successful. Based on Matt’s experience as a developer working for Google, Doordash, and a startup he founded, they examine tools for building extensions, as well as APIs they have access to. The conversation presents detailed issues such as cross-browser compatibilities to keep in mind when developing extensions and mechanisms in the browser to prevent security vulnerabilities, and finally examines how emerging platforms can help developers take advantage of exciting new possibilities with web extensions.

J.R. Storment and Mike Fuller discuss cloud financial operations (FinOps) with host Akshay Manchale. They consider the importance of a financial operations strategy for cloud-based infrastructure. J.R. and Mike discuss the differences between operating your own data center and running in the cloud, as well as the problems that doing so creates in understanding and forecasting cloud spend. Mike details the Cloud FinOps lifecycle by first attributing organizational cloud spend through showbacks and chargebacks to individual teams and products. JR describes the two levers available for optimization once an organization understands where they're spending their cloud budget. They discuss complexities that arise from virtualized infrastructure and techniques to attribute cloud usage to the correct owners, and close with some recommendations for engineering leaders who are getting started on cloud FinOps strategy.

Adam Dymitruk, CEO and founder of Adaptech Group, joins host Jeff Doolittle for an exploration of the event modeling approach to discovering requirements and designing software systems. Adam explains how the structured approach eliminates the specifics of implementation details and technology decisions, enabling clearer communication for all stakeholders while keeping conversations focused on the business opportunity. Using concrete examples of event modeling in practice, they examine event modeling in the context of other related approaches and methodologies, including event sourcing, event storming, CQRS, and domain-driven design.

Adam Warski, the co-founder and CTO of SoftwareMill, discusses Scala programming and the Tapir library. Scala is a general-purpose JVM language, and Tapir is a back-end library used to describe HTTP API endpoints as immutable Scala values. Host Philip Winston speaks with Warski about the implications of Scala being a JVM language, the Scala type system, the Scala community's view of functional vs. object-oriented programming, and the transition of the ecosystem from Scala 2 to Scala 3. The Tapir discussion explores why Tapir is a library and not a framework, how server interpreters work in Tapir, how interceptors work, and what observability features are included with Tapir.

John Ousterhout, professor of computer science at Stanford University, joined SE Radio host Jeff Doolittle for a conversation about his book, A Philosophy of Software Design . They discussed the history and ongoing challenges of software system design, especially the nature of complexity and the difficulties handling it. The conversation also explored various design concepts from the book, such as modularity, layering, abstraction, information hiding, maintainability, and readability.

In this episode, we explore the popular pytest python testing tool with author Brian Okken, author of Python Testing with pytest . We start by discussing why pytest is so popular in the Python community: its focus on simplicity, readability, and developer ease-of-use; what makes pytest unique; the setup and teardown of tests using fixtures, parameterization, and the plugin ecosystem; mocking; why we should design for testing, and how to reduce the need for mocking; how to set up a project for testability; test-driven development, and designing your tests so that they support refactoring. Finally, we consider some complementary tools that can improve the python testing experience.

Sergey Gorbunov of Axelar discusses blockchain interoperability, a technology that enables decentralized applications to work across multiple blockchain ecosystems. Host Philip Winston spoke with Gorbunov about programmable blockchains, distributed vs. centralized changes, the Ethereum virtual machine, Axelar's Cross-Chain Gateway Protocol and Cross-Chain Transfer Protocol, security issues, delegated proof of stake...

Uma Chingunde of Render compares building a PaaS with her previous experience running the Stripe Compute team. Host Jeremy Jung spoke with Chingunde about the role of a PaaS, building on public cloud providers, build vs buy, choosing features, user experience, managing databases, Series A vs later stage startups, and why internal infrastructure teams should run themselves like product teams.

Richard L. Sites discusses his new book Understanding Software Dynamics, which offers expert methods and advanced tools for understanding complex, time-constrained software dynamics in order to improve reliability and performance. Philip Winston spoke with Sites about the five fundamental computing resources CPU, Memory, Disk, Network, and Locks, as well as methods for observing and reasoning when investigating performance problems using the open-source utility KUtrace.

This week, Postgres server developer Bruce Momjian joins host Robert Blumen for a discussion of multi-version concurrency control (MVCC) in the Postgres database. They begin with a discussion of the isolation requirement in database transactions (I in ACID); how isolation can be achieved with locking; limitations of locking; how locking limits concurrency and creates variability in query runtimes; multi-version concurrency control as a means to achieve isolation; how Postgres manages multiple versions of a row; snapshots; copy-on-write and snapshots; visibility; database transaction IDs; how tx ids, snapshots and versions interact; the need for locking when there are multiple writers; how MVCC was added to Postgres; and how to clean up unused space left over from aged-out versions.