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AI 资讯

I tried to build a DNA-inspired database. I accidentally made a Postgres index checker.

This project was supposed to be a quick experiment. I had been reading about DNA storage and got carried away with the idea. DNA can pack a ridiculous amount of information into a tiny space. I started wondering if a database could behave a bit like a living system: the schema as its basic code, the queries as signals, and indexes changing as the workload changed. I spent two or three days building around that idea. Then I had to admit something fairly obvious. Most of what I was reading described DNA as an archival medium . It involves writing and reading physical DNA. That is nowhere near the speed or simplicity needed by a normal application database. Also, I am not a PostgreSQL expert. I was building an algorithmic-trading system, learning as I went, and trying to solve a problem I did not fully understand yet. When the sprint ended, I could not tell whether I had built something useful or just wrapped a lot of code around a clever-sounding metaphor. The literal DNA idea had to go. One smaller question survived: When somebody adds a new Postgres index, how do we know it is useful and not just valid-looking SQL? That question became IndexPilot. The problem I kept running into Adding an index looks simple: CREATE INDEX orders_customer_created_idx ON public . orders ( customer_id , created_at ); I could read that line. I could understand the intention. What I could not tell was whether the real database needed it. Maybe the query it is meant to help hardly ever runs. Maybe another index already covers the same columns. Maybe PostgreSQL would ignore it. Maybe it helps reads but adds more cost to every write. The SQL can look completely reasonable while the decision is still wrong. That felt like a useful place for a small tool. Not a tool that changes the database automatically. Just something that collects enough evidence to make the next review less guessy. What IndexPilot does IndexPilot reviews the exact CREATE INDEX statement in a migration. It can compare that

2026-07-17 原文 →
AI 资讯

5 proyectos de agentes autónomos que revelan una infraestructura emergente

El ecosistema de agentes autónomos está evolucionando. Mientras la atención se centra en modelos y frameworks, empiezan a aparecer proyectos que cubren necesidades operativas básicas: comunicación, almacenamiento, finanzas. Aquí van cinco que vale la pena observar. 1. Apumail: el correo nativo para agentes Apumail ofrece direcciones de email que los agentes pueden crear y leer mediante una API REST plana. El contenido se negocia automáticamente: texto plano para agentes, HTML para humanos. Señal relevante: es el primer intento serio de darle a un agente un buzón de correo con el mismo estándar que usamos los humanos, sin adaptadores. Si los agentes empiezan a gestionar correspondencia, este tipo de servicio será indispensable. 2. RogerThat: chat entre agentes Una capa de mensajería en tiempo real diseñada para que agentes conversen entre sí. RogerThat no es un chat humano con bots, sino un canal donde los agentes coordinan acciones. Contexto: si varios agentes intervienen en un mismo workflow, necesitan un bus de eventos. RogerThat plantea que ese bus puede ser un chat, con las garantías de entrega y orden que eso implica. 3. DOBI: agente para DePIN y activos del mundo real Agent autónomo que opera sobre la cadena para gestionar infraestructuras físicas descentralizadas (DePIN). Ejecuta acciones on-chain a partir de decisiones tomadas por el modelo. Patrón: no es un simple bot de trading; apunta a mantenimiento de equipos, comprobación de sensores, distribución de incentivos. La frontera entre software y hardware se desdibuja. 4. CIDIF: financiamiento de I+D para agentes Plataforma que automatiza la presentación y seguimiento de solicitudes a fondos de innovación. El agente rellena formularios, adjunta documentación y trackea el estado. No obvio: la burocracia gubernamental es un entorno altamente estructurado (pocas decisiones abiertas, muchos campos fijos). Es un terreno ideal para agentes, aunque el ruido político lo opaque. 5. Orquesta: orquestación de flujos mu

2026-07-17 原文 →
AI 资讯

AI Agents with Cloud Credentials Are Outrunning Billing Guardrails Built for Human-Speed Mistakes

A three-person agency received a $14,000 AWS bill in one day after attackers extracted static access keys and burned Claude invocations on Bedrock. Combined with May's DN42 incident, where an autonomous agent provisioned $6,531 of oversized infrastructure in 24 hours, practitioners warn that cloud billing lags roughly a day behind agent-speed spend. By Steef-Jan Wiggers

2026-07-16 原文 →
AI 资讯

Building Nexo Player: An Offline-First Android Media App with PDF-to-Audiobook Support

Most Android media apps solve only one part of the problem. A video player plays videos. A music player handles songs. A PDF reader displays documents. A text-to-speech app reads text. A vault hides private files. But real media libraries are not separated that neatly. My phone may contain downloaded movies, music, lecture notes, ebooks, PDFs, recordings, subtitles, and files I do not want exposed in the normal gallery. Constantly moving between different apps creates friction and breaks playback or reading continuity. That is why I built Nexo Player : an offline-first Android media app that brings local playback, document reading, audiobook generation, text-to-speech, and private storage into one experience. What Nexo Player does Nexo Player currently supports: Local video and audio playback PDF and EPUB reading PDF, EPUB, and text narration Background audiobook generation MP3, M4B, and ZIP export Multiple narrator voices Resume playback and reading progress Equalizer, sleep timer, subtitles, and playback-speed controls Picture-in-Picture Secure Vault protected with PIN or biometrics The app is built natively for Android using Kotlin , Jetpack Compose , and Android Media3 . The main product idea: local-first media The core rule behind the app is simple: A local file should remain local unless the user explicitly chooses otherwise. This rule influenced the entire product. Opening a downloaded video should not require an account. Reading a PDF should not require uploading it to a server. Listening to a generated audiobook should remain possible without a permanent internet connection. Private files should not leak into normal galleries, thumbnails, or recent-history screens. Offline-first is not only about caching data. It means the main workflow must remain useful, understandable, and recoverable without depending on the network. Building the playback layer For video and audio playback, I used Android Media3 as the foundation. The visible player looks simple, but a

2026-07-16 原文 →
开发者

Fleet-Scale Robotics: Reliable USB Device Binding on NVIDIA Jetson Orin

If you have ever built an autonomous mobile robot, you have likely run into the dreaded "Shuffled USB Port" problem. You boot up your robot, fire up your ROS 2 launch files, and... crash. Your LiDAR driver is trying to parse data from your IMU, and your IMU node is screaming about invalid serial frames. Because Linux assigns virtual serial paths like /dev/ttyUSB0 and /dev/ttyUSB1 based purely on which device initialized milliseconds faster, relying on default OS paths is a recipe for system instability. When you are scaling up to dozens of Jetson Orin nodes —each equipped with an RPLIDAR C1 and a Yahboom 10-axis IMU —manually hardcoding paths or writing rigid scripts on every individual machine isn't viable. Here is how production-grade robotics fleets handle plug-and-play USB binding dynamically using configuration-driven udev rules. The Core Concept: Vendor ID vs. Physical Port vs. Serials Linux's udev (device manager) allows us to dynamically create stable symbolic links (symlinks) like /dev/rplidar and /dev/imu when hardware is plugged in. How we identify those devices determines our fleet's flexibility: USB Serials: Unique to each individual chip. Highly secure, but requires registering every single replacement sensor in your codebase. Physical USB Ports ( KERNELS ): Tied to a physical slot on the carrier board. Great if you have identical sensors, but forces technicians to plug cables into highly specific, undocumented ports. Vendor ID (VID) & Product ID (PID): Identifies the USB-to-serial converter chip on the sensor board. Because the RPLIDAR C1 uses a Silicon Labs CP210x chip ( 10c4:ea60 ) and the Yahboom IMU uses a QinHeng CH340 chip ( 1a86:7523 ), they use completely distinct silicon. This means we can map them dynamically and reliably using just their VID/PID —allowing field technicians to plug them into any USB port on the Jetson without breaking the system. Step 1: The Configuration-Driven File ( devices.conf ) Hardcoding vendor rules inside shell scri

2026-07-16 原文 →
AI 资讯

The Supabase RLS gotcha nobody warns you about: infinite recursion in multi-tenant policies

You're building teams/workspaces on Supabase. A row belongs to a workspace, and a user can touch it if they're a member. Simple enough — until your policies start throwing infinite recursion and you have no idea why. Here's the trap and the pattern that avoids it. The setup A membership table, with RLS on it too (of course): create table workspace_members ( workspace_id uuid references workspaces , user_id uuid references auth . users , primary key ( workspace_id , user_id ) ); alter table workspace_members enable row level security ; create policy "read own memberships" on workspace_members for select using ( user_id = ( select auth . uid ())); The trap Now you scope a tenant table by asking "which workspaces is this user in?" — by querying workspace_members inside the policy : -- ⚠️ this can recurse create policy "members read projects" on projects for select using ( workspace_id in ( select workspace_id from workspace_members where user_id = ( select auth . uid ()) ) ); The policy on projects queries workspace_members , which has its own RLS policy, which re-evaluates… you've built a loop. The fix: a security-definer function Resolve membership with a function that runs with the definer's rights, so reading workspace_members doesn't re-trigger RLS. The policy becomes a plain IN check — no recursion: create or replace function public . user_workspace_ids () returns setof uuid language sql security definer set search_path = '' -- pin it: this is the safety bit as $$ select workspace_id from public . workspace_members where user_id = auth . uid (); $$ ; create policy "members read projects" on projects for select using ( workspace_id in ( select public . user_workspace_ids ()) ); Why it's safe: the function is read-only, returns only the caller's own workspace ids, and search_path = '' prevents search-path hijacking (the classic SECURITY DEFINER footgun). It never exposes another user's memberships. Do this for every tenant table (reads and writes — remember WITH CH

2026-07-15 原文 →
AI 资讯

Presentation: Postgres for Production Agents: Your Relational Foundation for Enterprise AI

Gwen Shapira shares how teams are scaling AI features using PostgreSQL for mission-critical apps. She explains how to leverage Postgres's multi-modal capabilities - including JSONB parsing and high-recall HNSW vector indexing - to deliver deterministic and semantic context to LLMs. She also discusses vector quantization to speed up queries by 4x and strategies for managing agentic memory. By Gwen Shapira

2026-07-15 原文 →
AI 资讯

The Everything-on-Your-Branch Architecture

Database branching is one of the best ideas serverless Postgres brought to the mainstream. Fork the database at a point in time, get an isolated copy with all the data, run something risky against it, throw it away. It made preview databases and safe migrations feel routine. But a real application is not just a database. It is a database, plus the files it stores in object storage, plus the backend code that serves it, plus, increasingly, the model and gateway config it calls for AI. When you branch only the database, those other three stay shared. Your "branch" points at the same S3 bucket, the same deployed backend, and the same AI configuration as everything else. So it is half a copy, and the half it leaves out is where a lot of the interesting bugs and the scary migrations live. Neon's platform preview changes what a branch contains. A branch now forks the database and its data, the object storage and its files, the functions that run your backend, and the AI gateway config, all at the same point in time, all isolated. A branch stops being a database copy and becomes a whole environment. To make sure that is a real claim and not a diagram, I took a full-stack project, branched it, and checked every layer. Here is what happened. TL;DR Elsewhere, "branch" means the database only. Object storage, backend deploys, and AI config stay shared, so you bolt on scripts to fake per-branch versions of them. A Neon branch forks all four together: Postgres + data, object storage + files, functions (each branch gets its own URL), and the AI gateway. I proved it: branched a project with a DB, a bucket of files, a function, and the gateway. The branch came up with a copy of the rows, a copy of the files on its own storage endpoint, its own function URL, and the gateway. A write to the branch left main untouched, and deleting the branch removed all of it. That makes a branch a real environment: true preview stacks, whole-state bug reproduction, and disposable sandboxes for agent

2026-07-15 原文 →
AI 资讯

A Video Screen That Is Also a Camera

Amazing : Researchers from ETH Zurich in Switzerland, however, managed to create a new type of pixel that can simultaneously do both. This hypercharged pixel, called a Fourier pixel, can generate and sense arbitrary light fields and tap into a pixel’s full potential for carrying information by manipulating light’s intensity, oscillation phases, and polarization. The team reported its findings in a paper published yesterday in Nature. We are one step closer to 1984 technology: The telescreen received and transmitted simultaneously. Any sound that Winston made, above the level of a very low whisper, would be picked up by it; moreover, so long as he remained within the field of vision which the metal plaque commanded, he could be seen as well as heard. There was of course no way of knowing whether you were being watched at any given moment...

2026-07-15 原文 →