A. Jesse Jiryu Davis's blog on MongoDB, Zen, and photography.| emptysqua.re
Here are my notes from the 2025 TLA+ Community Event. See also my colleague Murat Demirbas’s notes (he was one of the event’s organizers). The talks were all recorded, and the videos, slides, and abstracts are posted. Some years there are TLA+ “conferences” co-located with industry conferences, and some years there are “community events” co-located with academic conferences. This year was a community event, the first TLA+ community event in North America. There were about 20 parti...| A. Jesse Jiryu Davis
Holy Week services (Maundy Thursday, Good Friday) at Christ Episcopal Church in Poughkeepsie. The church has operated since the 1760s; the current building was erected in 1889. My friend Emily is the church’s assistant rector, she was ordained there last year. She invited me to photograph the services this month. --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- Shot with a Nikon F3 and a Nikkor 50mm f/1.2 on Portra 800 35mm film...| A. Jesse Jiryu Davis
April 9, 2025. Mohonk Preserve rangers training for rescue operations. I spent a day with them earlier, in March. --- --- --- --- --- --- --- --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
When you’re hunting for bugs with a nondeterministic test, how many times should you run the test? The program might be deterministic: the same input produces the same behavior. Presuming you’re confident this is the case, you could fuzz the input for a while, hoping to catch bugs. But if your program is nondeterministic, you must not only give it random inputs, you must re-test it on the same input many times, hoping to achieve high branch coverage and catch rare bugs. I was at the first...| A. Jesse Jiryu Davis
April 1, 2025. Zen priest Kenzen, formerly named Gessho, who was recently ordained at the Village Zendo in New York. --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
I look in the Bhagavad Gita and the life of radical abolitionist Benjamin Lay for examples: how do we live in stressful times, and how do we act when there are no good options? This is my March 30, 2025 dharma talk at the Village Zendo. Watch the video above, read the transcript below, or subscribe to my podcast. --- TRANSCRIPT Once upon a time, ages ago, there was a civil war. One family, the Kurus, had ruled the great kingdom of Hastinapura for many generations, but there was a succession d...| A. Jesse Jiryu Davis
March 25, 2025. Mohonk Preserve rangers training for rescue operations. They practiced building anchors, ascending and descending ropes, rescuing an unconscious climber hanging on a rope, and securing a patient in a litter. (More photos here.) --- --- --- --- --- --- --- --- --- --- --- --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
February 18, 2025. The local youth climbing team training at the gym. --- --- --- --- --- --- --- --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
I climbed with five friends in Red Rocks, outside Las Vegas. We had a medium-disappointing week. The sandstone there is fragile for a day or two after it rains, and it rained twice, so we were relegated to mediocre limestone climbing instead of world-class sandstone for most of the trip. Even on the limestone days our time was cut short by cold winds and occasional hail. My major objectives like The Fox and Cactus Massacre will have to wait. I never took out my Canon, but I had some fun with ...| A. Jesse Jiryu Davis
SwiftPaxos: Fast Geo-Replicated State Machines, in NSDI 2024, proposes a Paxos variant for networks with high latency, and different latencies between different pairs of nodes. Here’s a video of my presentation to the DistSys Reading Group, and a written review of the paper below. --- Table Of Contents Previous Paxi Paxos, as you know, is Leslie Lamport’s solution to the problem of consensus among unreliable nodes. The original Paxos achieved consensus on a single value (or “decree”),...| A. Jesse Jiryu Davis
Some of my photographer friends hand-make books, sculptures, etc. from their photos. They inspire me to be more inventive. Dustin holding his own mixed-media climbing art, framed with old climbing slings. Dustin training on his hangboard, framed in climbing chalk. Chris climbing Bonticou Crag, framed with local rocks. --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
October 22, 2023. There was stupidly dramatic light and clouds over New Paltz in the late afternoon that day. I forgot to publish this until now. --- --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
January 27, 2025. My climbing mentor, rock guide and artist Dustin Portzline, at home. --- --- --- --- --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
Which animals are sentient, and how can we liberate them from suffering? This is my January 23, 2025 dharma talk at the Village Zendo. I reviewed the philosopher Jonathan Birch’s book “The Edge of Sentience” and shared good news about humanity’s moral progress regarding animal welfare. Watch the video above, read the transcript below, or subscribe to my podcast. --- TRANSCRIPT I would like to introduce you to somebody. This is Sojourner Truth Armstrong Davis, she is a Chinese dwarf ha...| A. Jesse Jiryu Davis
December 2024. The Village Zendo’s winter meditation retreat in Garrison, NY, led by head student Ryugin. --- --- --- --- --- --- --- --- --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
This is a dharma talk I gave at the Village Zendo December 12, 2024, about my mother’s brain surgery and end-of-life decisions. Here’s the video and a transcript. --- Two months ago, my mom had emergency brain surgery. She had an artery in her brain that was basically completely blocked. This is the artery that feeds Broca’s area and the temporal lobes. These are the language centers, and language is my mother’s whole life. She’s a scholar of philosophy and law and religion. Reading...| A. Jesse Jiryu Davis
December 5, 2024. Peter’s Kill in the Gunks, during a snow shower. I ran out to get some photos of the snow falling in the morning light. While I was on the clifftop the storm returned and absolutely nuked me. It was impossible to keep my lens clean enough to take more photos, and the sunlight was blocked by clouds, so I came home. --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
November 23 and 24, 2024. Gan attempting Supper’s Ready, a 5.12a climb in the Gunks, with her climbing partner Kenny. --- --- --- --- --- --- --- --- --- --- --- Images © A. Jesse Jiryu Davis P.S.: On November 25, she sent.| A. Jesse Jiryu Davis
At MongoDB, we experimented to see if we could predict each DBaaS customer’s demand fluctuations, and auto-scale them using this foreknowledge. Senior Data Scientist Matthieu Humeau and I spoke about this experiment at Data Council and NYC Systems. Here’s the video from NYC Systems, and a written version is below. --- Replica Sets MongoDB is generally deployed as a group of servers, where one is the primary and at least two are secondaries. The client sends all writes to the primary, and ...| A. Jesse Jiryu Davis
Elizabeth Gross weaving a vessel for green burial. --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
I met a programmer of an antique tongue Who said: A vast, maintainerless pile of code Lies in GitHub. All around it flung Half-finished branches where development slowed, And READMEs full of bombast, heralding features Tell that its authors once with passion toiled Without release, their hearts chained to their object, Until their hearts gave out, their ardor spoiled: And in the manual these words appear: “My name is Fossymandias, the Greatest Project: Look on my works, ye Mighty, and despa...| A. Jesse Jiryu Davis
October 19, 2024. Climbing undocumented routes in the Gunks. --- --- --- --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
New York’s hottest club is NYC Systems. I’m speaking there October 17 with my colleague Matthieu Humeau. We’ll describe our experiment with predictive auto-scaling in MongoDB Atlas. The other presenter that night will be Andrew Werner, talking about instrumentation of compiled code. Unfortunately for you, registrations filled up a half hour after they opened. Join the waitlist! Or watch our presentation on the same topic at the Data Council conference this spring. NYC Systems is tech ta...| A. Jesse Jiryu Davis
September 21, 2024. Chris on Refrigerator Crack 5.10a and Cloud Nine 5.9 at the new Ant Lion Crag in the Gunks. --- --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
You can find yourself in a critical situation without warning. Is Zen practice preparing you? Here’s a dharma talk I gave to the Village Zendo on September 5, 2024, about the classic koan, “Nansen kills the cat.” The first couple seconds of the video were cut off, sorry. There’s a written version below. --- At the monastery on Mount Nansen, the monks of the eastern and western halls were arguing about a cat. This was late morning sometime around the year 830, in southern China. It was...| A. Jesse Jiryu Davis
Amazon MemoryDB: A Fast and Durable Memory-First Cloud Database, by six AWS engineers, in SIGMOD 2024. AWS hacked up Redis (I mean this respectfully) to produce a Redis-compatible database-as-a-service called MemoryDB, with better durability and consistency. Here’s a video of my presentation to the DistSys Reading Group, and a written review of the paper below. --- The Problem It's me, hi, I'm the problem, it's me. Redis is popular because it’s fast and supports fairly powerful data struc...| A. Jesse Jiryu Davis
The Washington Post says “the movement to diversify Silicon Valley is crumbling”, and the story is particularly dire for gender-diversity nonprofits: Girls In Tech has dissolved, so has Women Who Code, and software companies have sharply cut their grants to others. But were they helping? The article links to this Department of Labor chart which shows women’s share of all STEM employment has grown from 25% in 2000 to only 26% in 2022. For some reason the Post didn’t cite a worse statis...| A. Jesse Jiryu Davis
Sam Altman and Arianna Huffington plan to make an AI health coach, which will address chronic illness by encouraging people to eat better, take their medications, and get more sleep and exercise. Consider what it’s like to be a busy professional with diabetes. You might be struggling to manage your blood-sugar levels, often missing meals and exercise due to a hectic schedule. A personalized AI health coach, trained on your medical data and daily routines, could provide timely reminders to t...| A. Jesse Jiryu Davis
August 2024. The Village Zendo’s summer retreat. Walking meditation, 5am meditation by candlelight, and Zen student Seiryu’s first dharma talk. --- --- --- --- --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
June 26, 2023. “Pride Climb & Glow Night” at the Gravity Vault climbing gym in Poughkeepsie. --- --- --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
June 16, 2024. The “Descending and Ascending the Mountain Ceremony”, or Shisanshiki, at the Village Zendo in NYC. Our abbot Enkyo O’Hara Roshi retired and was succeeded by Shinryu Sinclair Roshi. --- --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
June 15, 2024. Climbing in Lost City, an undocumented area of the Gunks. The local tradition prohibits publishing information about climbing routes here. The first image is of Dustin Portzline on “Keelhauled”, an ungraded roof-crack boulder problem. The others are on a nameless 5.9 route. --- --- --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
June 11, 2024. The Mohonk Trail Builders lifting big rocks to build a trail in the Mohonk Preserve. --- --- --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
June 7, 2024. My friends climbing Absurdland in the Gunks as a storm approaches. --- --- --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
June 3, 2024. A Gunks cliff at sunset. I did a quick hike to the cliff in the evening and scrambled up, then I alternated taking photos and eating a sandwich as the light changed. A couple of these are HDRs: I steadied my digital camera on some rocks and took three exposure-bracketed frames, then merged them in Lightroom. The blossoms are mountain laurel. --- --- --- --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
Detock: High Performance Multi-region Transactions at Scale, SIGMOD 2023. This paper is about strict serializable transactions in a geo-distributed database. It’s named “Detock” for deterministic deadlock avoidance. My presentation to the Distributed Systems Reading Group is above, and my written summary is below. --- Calvin Detock’s goals: Strict-serializable, multi-region transactions. Low latency and high throughput under high contention. Handle contention between multi- and single...| A. Jesse Jiryu Davis
Timestamp as a Service, not an Oracle, by authors from Alibaba Cloud, in Proceedings of VLDB this year. Watch my presentation to the Distributed Systems Reading Group above, or read my summary below. Timestamp Oracles Priestess of Delphi (1891) by John Collier An oracle is someone who speaks for a god and reveals divine knowledge. In computer science we’ve used “oracle” to refer to theoretical machines that could do something impossible, like solve the halting problem or produce truly r...| A. Jesse Jiryu Davis
MongoDB implemented a consistency level called causal consistency in 2017 (version 3.6). It’s quite a handy consistency level, strong enough for most applications and still performant. I helped design the API for causal consistency, but when we released it I dropped the ball and didn’t publicize or document it well. MongoDB’s causal consistency didn’t get the fame it deserved in 2017; I’ll try to rectify that now. MongoDB implements a Raft-like consensus protocol. Most people deploy...| A. Jesse Jiryu Davis
April 15, 2024. Monks at Holy Cross, an Anglican Benedictine monastery in the Hudson Valley. See part 1 here. --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
March 24, 2024. A shuso hossen ceremony at the Village Zendo. Sherri Jyakuen Posey gave her first dharma talk and became a senior Zen student. --- --- --- --- --- --- --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
March 5, 2024. Monks at Holy Cross, an Anglican Benedictine monastery in the Hudson Valley. See part 2 here. --- --- --- --- --- --- --- --- --- --- --- --- --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
I gave a talk at the New Paltz Zen Center against doomerism. We vow to bear witness to all the suffering in the world, but there’s no reason to be gloomy about it. Let’s be cheerful bodhisattvas and enjoy our lives! --- Here’s three images. When you read the news, or you think about the state of the world, which one are you? What’s your state of mind? This is Edvard Munch’s “The Scream”, painted in 1893. There’s an emaciated figure, holding its head in its hands and its mouth ...| A. Jesse Jiryu Davis
March 5, 2024. An ordination ceremony for Emily Carter at Christ Episcopal Church in Poughkeepsie. --- --- --- --- --- --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
February 2024. Photos of my friends (and one friendly stranger) sport-climbing on the limestone crags near San Juan (Monagas and Flying Coconut). --- --- --- --- --- --- --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
Ptolemy Map, 1482 In 2015 some Facebook researchers threw down a gauntlet, challenging anyone who dared to provide stronger consistency in big, heterogeneous systems. In 2023, some researchers (mostly Portuguese) responded with Antipode: Enforcing Cross-Service Causal Consistency in Distributed Applications. Antipode defines an interesting new consistency model, cross-service causal consistency, and an enforcement technique they claim is practical in such systems. Motivating Example Here’s ...| A. Jesse Jiryu Davis
Leases: An Efficient Fault-Tolerant Mechanism for Distributed File Cache Consistency, Cary G. Gray and David R. Cheriton, 1989. Old and good. I read this simple paper because it seems to be ground zero for timed leases in distributed systems, in which I’m now intensely interested. The Protocol The authors discuss a distributed file system, e.g. for a network of diskless workstations connected to a shared file server. (The file server itself is a single machine, not replicated. Yes, it’s a...| A. Jesse Jiryu Davis
Christiaan Huygens by Caspar Netscher, 1671. This is a review of Exploiting a Natural Network Effect for Scalable, Finegrained Clock Synchronization, from Stanford and Google researchers. It describes Huygens, a protocol for very accurate clock synchronization, plus (an undersold benefit) very accurate measurements of one-way network latency. I read it because the Huygens protocol is used by Nezha, which I reviewed last week. The Huygens and Nezha papers share two authors. Motivation As Barba...| A. Jesse Jiryu Davis
This is a review of Nezha: Deployable and High-Performance Consensus Using Synchronized Clocks, from NYU and Stanford researchers last year. To understand this paper I had to relearn how quorums work in Paxos and Fast Paxos, so we’ll start there. Table Of Contents Classic Paxos Quorums In Paxos there are proposers, acceptors, and learners. Each server usually plays all three roles, but the protocol’s often described as if the roles are separate (confusingly, in my opinion). The protocol i...| A. Jesse Jiryu Davis
January 1, 2024. Our young Chinese dwarf hamster Sojourner Truth Armstrong Davis. --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
November 25, 2023. Hiking the Bonticou Crag and Table Rocks loop in the Gunks, upstate New York. Portra 400 with my Mamiya 7. --- --- --- --- --- --- --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
December 1, 2023. Climbing with Jennifer in the Dickie Barre area of Peter’s Kill, the Gunks. Portra 400, Mamiya 7. --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
December 2023. The Village Zendo’s annual year-end Zen retreat, at the Garrison Institute (a former Catholic monastery) on the Hudson River. This year I was a monitor of the meditation hall, responsible for everyone staying awake, sitting up straight and silent and still, finding a comfortable posture, and keeping to the schedule. We had a lot of inexperienced meditators who were clearly in pain after the first day. I met with them and discussed options for sitting on a chair, or a seiza be...| A. Jesse Jiryu Davis
In 2022, Marc Brooker argued that formal methods like TLA+ can check distributed systems' correctness but not their performance. Since then, I’ve been searching for good performance modeling tools. Queue theory seems like a foundation for performance modeling, so I learned some queue theory, although I read the wrong book. That book tried to teach me to analyze queue networks by solving intricate equations, but for most queue networks the equations can’t be solved, and for the rest I can...| A. Jesse Jiryu Davis
October 11, 2023. Boulderers in the West Trapps area of the Gunks. Shot with a Mamiya 7 on Portra 400. --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
October 22, 2023. Warrior’s Way Falling and Commitment, a one-day climbing class taught in the Gunks by Dustin Portzline. Students learned to place trad gear and practiced falling on it. --- --- --- --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
Distributed Transactions at Scale in Amazon DynamoDB, USENIX ATC 2023. This paper builds on last year’s DynamoDB scalability and reliability paper. It’s unrelated to the obsolete Dynamo system described in 2007. The current paper describes how Amazon added transactions to their existing key-value store. Their requirements were: ACID, where “C” is serializable, but not strict serializable: transactions can appear to happen in any order. This will be important. Transactions update items...| A. Jesse Jiryu Davis
September 27 and October 1, 2023. Ivan, an itinerant climber, and his dog Rudy. I can’t decide which is my favorite photo of him making breakfast from his truck, or which is my favorite of him lead-rope soloing Teeny Face (5.10a). This was my first time shooting climbing with a film camera, much less with medium format. Given the difficulty I’m pretty happy with the results. --- --- --- --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
September 17, 2023. My first time out with my Mamiya 7 shooting Kodak Portra 400. The Peter’s Kill climbing area, in the Gunks, at dusk. --- --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
Our Chinese hamster Shirley Chisholm Armstrong Davis died last week. She was indomitable as her famous namesake, guarding her territory against all comers. She explored the house boldly, ramming her clear plastic ball against obstacles, and when she was asked to edit Jennifer’s manuscripts her critique was pitiless. Shirley and her sister, Fannie Lou Hamer Armstrong Davis, arrived in our New York City apartment in 2021. They shared a mutual affection and managed their domestic arrangements ...| A. Jesse Jiryu Davis
PolarDB is Alibaba’s cloud-native SQL database. It has the now-typical architecture of one read-write (RW) node and several read-only (RO) nodes as hot backups, sharing a disaggregated storage layer. Figure 1 from the paper. Each RO has an in-memory cache; to keep this updated, the RO streams the write-ahead log (WAL) from the RW and replays it on the RO’s locally cached data. Nevertheless the RO’s cache is usually a bit out of date, so RO queries may return stale (inconsistent) data. A...| A. Jesse Jiryu Davis
Performance Modeling and Design of Computer Systems: Queueing Theory in Action, by Dr. Mor Harchol-Balter. We are A. Jesse Jiryu Davis, Andrew Helwer, and Murat Demirbas, three enthusiasts of distributed systems and formal methods. We’re looking for rigorous ways to model the performance of distributed systems, and we hoped this book would point the way. We followed the author’s undergrad syllabus, although we were disappointed at its focus on single-threaded task queues. Most of our work...| A. Jesse Jiryu Davis
SelfTune: Tuning Cluster Managers, by authors from Microsoft Research, regular Microsoft, and Stony Brook University, at NSDI (Networked Systems Design and Implementation) 2023. Here’s a presentation I gave to the distributed systems reading group, a written version is below. The only reason I review papers is because I like finding old images, here’s a guy tuning a piano. --- The Problem This paper is about cluster managers, software systems like Kubernetes or Docker Swarm, that manage a...| A. Jesse Jiryu Davis
June 30 and July 1, 2023. Traditional Climbing and Mental Training Camp, a two-day climbing class taught in the Gunks by Dustin Portzline. Students learned to place trad gear and practiced falling on it. --- --- --- --- --- --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
May 19, 2023. Warrior’s Way Falling and Commitment, a one-day climbing class taught in the Gunks by Dustin Portzline. Students learned to place trad gear and practiced falling on it. --- --- --- --- --- --- --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
May 7, 2023. Irene Yee taught a climbing photography clinic in the Gunks, in collaboration with Rise Outside. I had some experience hanging from a rope and photographing climbers before I took the class. But Irene presented principles, methods, and tricks that went far beyond what I had figured out on my own. Here’s a selection of photos I took during her clinic. --- --- --- --- --- --- --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
Computers are infuriating. At PyCon 2023 I talked about consistency and isolation in databases, and showed Python implementations of four isolation levels. Here’s the PyCon video and here’s a Talk Python podcast interview with Michael Kennedy (episode page). The subject goes a bit deeper than I could cover in 30 minutes; here are links for further reading. First, orient yourself with Kyle “Aphyr” Kingsbury’s map. Isolation Basics Granularity of Locks in a Shared Data Base, Gray et. ...| A. Jesse Jiryu Davis
My friend Andrew Helwer argues that the best way to communicate an algorithm is with PlusCal or Python. He has “come to believe that both are superior to an ad-hoc unspecified pseudo-math language,” of the sort that researchers often invent for their papers. He recommends a subset of Python that avoids “fancy features” like list comprehensions, and avoids the standard library. He shows an apt example: a 43-year-old algorithm that was specified in pseudocode and has therefore been plag...| A. Jesse Jiryu Davis
Distributed Reset, by Anish Arora and Mohamed Gouda, in IEEE Transactions on Computers, 1994. Say you have a distributed system, and each node wants the ability to reset all the nodes to some predefined state. “Distributed Reset” is a bolt-on protocol you can add to your system. The protocol involves constructing a spanning tree and diffusing the reset message in three waves through the tree. Table Of Contents --- Spanning tree Arora and Gouda’s goal is to augment any distributed system...| A. Jesse Jiryu Davis
Cornus: Atomic Commit for a Cloud DBMS with Storage Disaggregation, by Zhihan Guo, Xinyu Zeng, Kan Wu, Wuh-Chwen Hwang, Ziwei Ren, Xiangyao Yu, Mahesh Balakrishnan, and Philip A. Bernstein, at VLDB 2022. This paper describes some optimizations to two-phase commit on top of cloud storage. If you’re using cloud storage and 2PC, this protocol will reduce commit latency and avoid 2PC’s dreaded “blocking problem”. --- Table Of Contents Background: Two-Phase Commit Let’s say we have a par...| A. Jesse Jiryu Davis
I spent most of last year earning no income, and I also spent a lot of time learning about Effective Altruism. The EA philosophy, as I understand it, is that people who can afford to be charitable ought to give some money to the most effective charities. We should send money where it will do the most good, even if it helps distant strangers rather than the people we know in our families and communities. As I said in a dharma talk last year, Effective Altruism bears some resemblance to the pri...| A. Jesse Jiryu Davis
Paxos Quorum Leases: Fast Reads Without Sacrificing Writes, by Iulian Moraru, David Andersen, and Michael Kaminsky, in SoCC 2014. It’s about Paxos, but don’t be intimidated: this is an accessible paper about speeding up linearizable reads in geo-distributed groups of servers, supposedly without harming write performance too badly. Table Of Contents The Problem In a replicated system like Multi-Paxos, a client sends a write request w to the leader, which forwards it to the followers. When ...| A. Jesse Jiryu Davis
December 2022. The Village Zendo’s annual year-end Zen retreat. We held it at the Garrison Institute in upstate New York, as usual. Well, it was usual before the pandemic, but this is our first in-person winter retreat since year-end 2019, so I didn’t take it for granted. The Garrison Institute was a Capuchin monastery built in 1923, then converted to a retreat center in 2003; now it hosts retreats for all kinds of spiritual communities. I notice in these photos how the Christian bones sh...| A. Jesse Jiryu Davis
Rex: Replication at the Speed of Multi-core by Zhenyu Guo, Chuntao Hong, Mao Yang, Dong Zhou, Lidong Zhou, and Li Zhuang at EuroSys 2014. Like the C5 paper I just reviewed, Rex is about improving asynchronous replication performance on multi-core, but I thought the C5 paper was humdrum whereas Rex is thought-provoking. Warm up your neurons because they're going to get a workout. Background Usually in asynchronous replication, one server is the leader for a while and makes modifications to its...| A. Jesse Jiryu Davis
December 18, 2022. Jo An, Keishin, and Ruby the dog practicing at the New Paltz Zen Center in upstate New York. --- --- --- --- --- --- --- --- --- --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
As planned, I returned from an 8-month leave and resumed work for MongoDB last week. My intention for the long break was to climb a lot, practice being afraid, get more comfortable on the wall, and have more fun climbing. My secondary goal was to read more computer science research and focus on learning, freed of daily engineering responsibilities. I accomplished the first goal and not the second, and I’m completely satisfied with that. Climbing Photo: Rita Strauss The climbing style here i...| A. Jesse Jiryu Davis
C5: Cloned Concurrency Control that Always Keeps Up, by Jeffrey Helt, Abhinav Sharma, Daniel J. Abadi, Wyatt Lloyd, Jose M. Faleiro, in VLDB 2022. The authors describe a useful optimization for primary-backup replication, but they don’t break new ground. Here’s a video presentation I made to the DistSys Reading Group about this paper, and my written review below. --- I don’t have images of clones or anything apropos, but it’s snowing in New Paltz, NY so I’ll try to entertain you wit...| A. Jesse Jiryu Davis
May 18, 2022. My partner Jennifer Keishin Armstrong and I visited the Johns Hopkins Center for Psychedelic and Consciousness Research in Baltimore to interview the director, Roland Griffiths, and observe a psilocybin session. We staged a session with one of their staff acting as the research participant so we could witness and photograph the whole process, including the preparation of the psilocybin pill. Our story appears in the November print issue of Lion’s Roar magazine and online. --- ...| A. Jesse Jiryu Davis
Merriam-Webster’s time traveler page shows you words that were added to the dictionary in a given year. The year I was born, 1978, is the year that bed-and-breakfasts, bodice rippers, and BFFs joined the canon. You won’t be surprised that in the late 70s juiceries and meaderies were entered in the dictionary, along with lookism and pad thai. Information technology, my field, earned its place in Merriam-Webster’s, and the job title “intrapreneur” was recognized. I haven’t heard of ...| A. Jesse Jiryu Davis
November 5, 2022. My friends participating in a casual bouldering competition in Peter’s Kill, part of the Gunks climbing region in upstate New York. --- --- --- --- --- --- --- --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
October 29, 2022. A ceremony at the Village Zendo in which Jeff Shugo Berman gave his first dharma talk and was promoted to senior Zen student. This was one of our first big hybrid ceremonies at the Village Zendo, with multiple cameras and microphones livestreaming the event to attendees on Zoom. --- --- --- --- --- --- --- --- --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
I attended my first High Performance Transaction Systems (HPTS) conference last week. Here are my notes on the talks. Please don’t quote or trust me; these notes are based on what I heard, frantically typed, and minimally polished later. I have certainly misunderstood a lot, especially in areas outside my expertise. And even if I heard them correctly, treat researchers' claims skeptically! Table Of Contents Intro Keynote: HPTS Comes Full Circle - James Hamilton (Amazon) High performance tra...| A. Jesse Jiryu Davis
Photos from a 10-day Zen meditation retreat, in a Catholic retreat center in rural Connecticut. This was my Zen community’s first in-person sesshin since December 2019. In the years between, I’ve been disconnected from the Village Zendo. While many of the sangha members met on Zoom for zazen, chanting, and various events, I focused on other practices and teachers. Climbing has been my main spiritual practice. To sit again knee-to-knee with my sangha felt like coming home to my chosen fami...| A. Jesse Jiryu Davis
May 29, 2022. Photos of my friends climbing in Peterskill in upstate New York. I learned a bit about climbing photography from Spencer McKay; now I’m trying it out. --- --- --- Images © A. Jesse Jiryu Davis| A. Jesse Jiryu Davis
Should the temporal logic of actions also do performance modeling?| emptysqua.re