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100 城时区页给跨区调度当速查,DST 自动算

100 城时区页给跨区调度当速查,DST 自动算 作者是 数据管道 / 跨时区调度 方向的开发者。这篇不是广告,是踩坑记录 + 顺手做的工具。 背景 做 数据管道 / 跨时区调度 时,时间戳转换是最常被低估的雷区。16 个时间戳工具(Unix 转换/时区/ISO8601/Cron/Duration…) 已覆盖日常;但每个语言/框架的坑都不一样,所以又补了 30 个语言/框架时间戳页(python/javascript/java/sql/…),每页含 6 个真实坑。 我踩过的坑(举几个) 秒 vs 毫秒:前端 Date.now() 是毫秒,后端常存秒,混用差 1000 倍。 时区不是字符串:存 UTC、展示本地,别把本地时间当 UTC 落库。 2038 问题:32 位系统 time_t 在 2038-01-19 溢出,老系统要提前查。 夏令时:一年有两次重复/缺失的本地时间,跨区调度尤其坑。 我顺手做的东西 转换速查页: https://gotimestamp.com/timezone/new-york 相关语言页: https://gotimestamp.com/timezone/london 开源 MCP: https://github.com/caresotin/tsforge-mcp —— 把时间戳转换/校验直接接进 LLM 工作流,不用手算。 小结 时间戳没那么简单,但工具到位就省心。上面都是免费、开源、可直接用的,希望对同样踩坑的人有帮助。

2026-08-04 原文 →
AI 资讯

RAG vs. Semantic Layer: Why AI Needs Deterministic Governance

Half the market is arguing about whether RAG or a semantic layer is the right foundation for enterprise AI. They are not competing. They answer different questions, and most teams need both. Two shapes of question Every question an agent receives breaks into one of two forms: "What did we say about X?" — lives in contracts, policies, tickets, docs. Unstructured. RAG was built for this. "What is true about X?" — lives in your warehouse and governed metrics. Structured. A semantic layer was built for this. Treating them as rivals is how teams end up with a system that can quote the pricing policy but cannot tell you this quarter's realised price. Where each one breaks RAG Semantic layer Good at Retrieving relevant prose Resolving definitions and joins Fails on Aggregation, math, current state Anything not modelled as data Permissions Flattened at ingest, rebuilt at query time Compiled per person, per query Answer stability Varies with retrieval ranking Identical by construction Audit story Cites a chunk Reproduces the exact SQL The permissions row is the one that ends pilots. A retrieval index that ingested everything has, by construction, assembled your most sensitive object — and reconstructing entitlement at query time is guesswork. The layer that actually decides Neither a document chunk nor a metric definition is worth much until something compiles it into a governed query and runs it. That is the piece most architectures are missing: intent → context resolution → constrained planning → governed execution . RAG can feed the first step. It cannot perform the last three. Point an agent at raw tables and the best models score in the low teens on real enterprise data. Give the same model compiled, governed context and it clears the high nineties. The retrieval quality was never the bottleneck. The full breakdown — the precise division of labour, why hybrid architectures win, and how compile-time governance closes the gap RAG cannot — is here: 👉 RAG vs. Semantic Layer

2026-08-04 原文 →
AI 资讯

Best Vector Databases for AI Applications in 2026

Vector databases have become the backbone of AI applications, powering semantic search, RAG systems, recommendation engines, and multi-modal AI. With the market maturing rapidly in 2026, choosing the right vector database impacts everything from query latency to operational costs. We ranked the 8 best options based on performance, scalability, ease of use, and enterprise readiness. TL;DR: Ranked 8 best vector databases: Pinecone leads for managed simplicity, Weaviate for flexibility, Milvus for open-source scale, and pgvector for PostgreSQL-native teams. Selection depends on your scale, latency requirements, and existing infrastructure. Key Evaluation Criteria for Vector Databases Modern vector databases must excel across multiple dimensions. We evaluated each option on: query performance (latency at various scales, index types supported), scalability (horizontal scaling, multi-tenancy), data type support (dense vectors, sparse vectors, multi-modal embeddings), integration ecosystem (SDKs, LangChain/LlamaIndex support), and operational maturity (hosting options, backup, monitoring). Query performance: P95 latency at 1M, 10M, and 100M vector scales Scalability: Horizontal scaling, sharding, multi-tenancy Data type support: Dense vectors, sparse vectors, binary vectors, multi-modal Integration: SDK availability, LLM framework support, MCP compatibility Operations: Self-hosted vs. managed, backup, monitoring, compliance Ranking: The 8 Best Vector Databases for AI Applications ### 1. Pinecone Pinecone remains the most popular fully-managed vector database, known for its simplicity and reliability. The 2026 release adds sparse-dense hybrid search, serverless tier with sub-millisecond P99 latency, and namespace-based multi-tenancy. Its serverless pricing model makes it cost-effective for variable workloads. * **Best for:** Teams wanting fully managed vector search without operational overhead * **Pros:** Zero operations, excellent performance, simple API, strong ecosystem

2026-08-04 原文 →
AI 资讯

How I Segmented Millions of Users in Just a Few Milliseconds

User segmentation requirement Imagine you need to send a push notification to users who satisfy all of the following conditions: Push notification is enabled User is a VIP Active within the last 30 days Following the Voucher Hot category The traditional approach is to query multiple tables: SELECT DISTINCT u . id FROM users u JOIN user_configs c ON c . user_id = u . id JOIN devices d ON d . user_id = u . id JOIN follows f ON f . user_id = u . id WHERE c . push_optin = 1 AND c . mute = 0 AND d . fcm_token IS NOT NULL AND f . category = 'voucher_hot' AND u . last_active >= NOW () - INTERVAL 30 DAY ; As your user base grows into the millions, every campaign requires joining multiple large tables, filtering millions of records, and repeatedly computing the same audience. Query latency increases significantly, making real-time segmentation increasingly difficult. A Different Approach Instead of querying the database every time, we precompute each boolean attribute as a bitmap. Think of a bitmap as a huge array containing only 0 and 1, where the index corresponds to the user ID. For example, a bitmap representing whether a user has enabled push notifications: User ID : 0 1 2 3 4 5 6 7 Bitmap : 1 0 1 1 0 0 1 1 To check whether user 123 has enabled notifications, simply read bit 123. 1 → enabled 0 → disabled Each bitmap represents exactly one boolean property: bitmap:push_optin bitmap:vip bitmap:active30 bitmap:follow:voucher_hot Memory Usage Bitmap is extremely memory efficient. Each user requires only one bit. For 1 million users: 1.000.000 bits ~ 125.000 bytes ~ 122 KB That means every segment only consumes about 122 KB of Redis memory. Even 100 different segments require only around 12 MB . Finding Intersections Suppose you want all users that are: VIP AND Push Opt-in AND Active30 AND Following Voucher Hot Redis can calculate the result with a single command: BITOP AND result vip push_optin active30 follow_voucher_hot Need the number of matched users? BITCOUNT result No

2026-08-03 原文 →
AI 资讯

Part 5: SQL Parsing: Turning Strings Into Commands

In Parts 1-4, we built a transactional key-value store. It has WAL for durability, memtables and SSTables for storage, compaction to control file growth, and transactions for atomic multi-key writes. Now we move to the query layer where users can actually fire SQL queries like: CREATE TABLE payments ( amount INT , id STRING , status STRING , captured BOOL , PRIMARY KEY ( id )) INSERT INTO payments VALUES ( 500 , payment_1 , pending , 1 ) SELECT * FROM payments WHERE id = payment_1 In this blog and the next one we answer: How do we translate SQL strings into operations our key-value store already understands? This post focuses on the first half of that bridge, which is parsing SQL into structured commands. In the next post, we will take those commands and turn CREATE TABLE and INSERT into bytes on disk. The Core Idea: SQL Becomes Structured Data The storage engine does not understand SQL. It understands keys, values, WAL entries, memtables, SSTables, and transactions. So the SQL layer has two jobs: Parse a human-readable SQL string into a structured object. Translate that structured object into key-value operations. For example: CREATE TABLE payments (...) -> CreateTable{TableName: "payments", ColumnDetails: ...} INSERT INTO payments VALUES (...) -> InsertIntoTable{TableName: "payments", ColumnValues: ...} SELECT * FROM payments WHERE id = payment_1 -> SelectFromTable{TableName: "payments", QueryConditions: ...} Once we have these structs, the rest of the database can stop dealing with raw strings. Why Not Parse SQL Directly in the DB Layer? Imagine if db.CreateTable() directly walked through the SQL string and also updated storage. That would mix two very different responsibilities: parsing grammar, executing database operations. Keeping them separate makes the system easier to reason about. The parser validates syntax and builds an AST. The DB layer receives that AST and decides what to store. An AST, or Abstract Syntax Tree, is just a structured representation of

2026-08-03 原文 →
开发者

Atomic Money: Making a PHP/MySQL Wallet Safe Under Concurrency

The lost-update bug that quietly corrupts homegrown wallet balances — and the five disciplines we used across PayWithToken to make money movement correct under concurrency. There is a bug that lives in a large share of the world's homegrown wallet systems. It doesn't throw an error. It doesn't show up in tests. It surfaces months later as a balance that is quietly, inexplicably wrong — and in a payments system, a wrong balance is either a customer who has lost money or a company that has given it away. This is the story of that bug, why the "obvious" wallet code causes it, and the handful of disciplines we used across PayWithToken to make money movement correct under concurrency. The bug: lost updates Here is wallet code almost everyone writes first. Credit a user's balance: // DON'T do this $row = $db->query("SELECT balance FROM users WHERE id = $id")->fetch(); $new = $row['balance'] + $amount; $db->exec("UPDATE users SET balance = $new WHERE id = $id"); Read the balance, add to it in PHP, write it back. It works perfectly — until two things happen at the same time. Picture a wallet at ₦1,000. Two credits of ₦500 arrive simultaneously — say a bank webhook and the user tapping "confirm" on their phone: Request A reads balance = 1000. Request B reads balance = 1000 (A hasn't written yet). A computes 1500, writes 1500. B computes 1500, writes 1500. Two credits landed; the balance rose by ₦500. ₦500 vanished. This is a lost update, and it is a race condition, which means it is invisible until you have real concurrent traffic — exactly when you can least afford it. The debit version of the same bug lets a balance go negative or double-spends a token. Fix #1: let the database do the arithmetic The read-modify-write happened in PHP, across three round trips, with a gap where another request could interleave. The fix is to make the update a single atomic statement and let the database's row lock serialise it: // DO this — one atomic statement $db->prepare("UPDATE users SET

2026-08-03 原文 →
AI 资讯

SQL Patterns Hidden Inside Social Networks

From the outside, social features seem like something straightforward: follow a user, like a post, see a feed, but when you attempt to implement them at any real scale you find that every single one is something you've got to be aware of, a pattern, a well-documented query pattern with all its failure modes. Here's a step-by-step look at four of them: adjacency list, fan-out feed, mutual-friends join, and some graph traversal that SQL wasn't really designed for. The adjacency list and why "who do I follow" isn't free A follow relationship is usually modeled as a plain adjacency table: follows(follower_id, followee_id, created_at) . That's the whole schema, and it's deceptively adequate for a long time. The first place it breaks is when you need "who do I follow that also follows them", mutual connections, because that's a self-join against the same table: SELECT f2 . followee_id FROM follows f1 JOIN follows f2 ON f1 . followee_id = f2 . follower_id WHERE f1 . follower_id = : user_id AND f2 . followee_id != : user_id ; This query is ok if the fan-out is low. It feels like it's no longer fine when a few accounts have a few hundred thousand joins, because join now needs to walk a correspondingly large intermediate result set per request. The typical solution isn't a better query, it's a better index and a cap. composite indexes on (follower_id, followee_id) and (followee_id, follower_id) so both directions of the join hit an index-only scan, plus a LIMIT applied early so the planner doesn't materialize more rows than the response will ever use. The fan-out feed problem The “social systems” hard problem is the timeline: display to me my feed of what people I follow posted recently, in order. There are two ways to construct it and they are both right - anything else and outages happen. Fan-out on write means that when a user posts, you insert a row into every follower's feed table immediately. Reads are then a trivial SELECT * FROM feed WHERE user_id = :id ORDER BY creat

2026-08-02 原文 →
AI 资讯

Começando minha jornada em Dados e Tecnologia

Olá, comunidade DEV! Meu nome é Beth Rodrigues e este é o meu primeiro post por aqui. Durante muito tempo, minha relação com tecnologia esteve ligada ao uso das ferramentas no dia a dia de trabalho. Planilhas, sistemas, relatórios e processos faziam parte da minha rotina, mas em algum momento comecei a enxergar algo diferente: por trás dos dados existiam histórias, oportunidades de melhoria e decisões que poderiam ser mais inteligentes. Foi assim que comecei minha transição para a área de Dados. Minha jornada está sendo construída passo a passo: estudando SQL, Excel, Power BI, Python e conceitos de análise de dados. Também tenho explorado ferramentas de inteligência artificial, automações e formas de transformar problemas reais em soluções. Uma das coisas que mais me motivam é perceber que dados não são apenas números em uma tabela. Eles podem ajudar uma empresa a entender seus clientes, melhorar processos e encontrar caminhos mais eficientes. Atualmente estou criando pequenos projetos para praticar, aprender e construir meu portfólio. Quero compartilhar por aqui meus aprendizados, erros, descobertas e experimentos nessa caminhada. Acredito muito que aprender tecnologia é como montar um grande quebra-cabeça: no começo algumas peças parecem não fazer sentido, mas aos poucos a imagem começa a aparecer. Espero trocar experiências com pessoas da comunidade, aprender com quem já está nessa estrada e também contribuir compartilhando minha evolução. Que venha essa nova fase! 🚀

2026-08-02 原文 →
AI 资讯

Your agent's memory is a vector store. Ask it "how many" and watch it fall over.

Originally published at nlqdb.com/blog The standard agent-memory build is an afternoon of work: embed every fact worth keeping, upsert it into a vector store, and before each reply pull the top-k most similar memories back into context. And for what it's built for, it works. Ask "what did this user say about the Berlin migration" and the right snippets come back, ranked by cosine distance. Recall is solved enough that it feels like memory is solved. Then the agent has been running for a month, and you ask its memory a different kind of question: "how many users asked about pricing this month?" "Average deal size per stage?" "Top 10 topics I logged, ranked by count?" The store dutifully returns the twenty memories most similar to the question text , the LLM eyeballs them, and you get a confident, specific, wrong number. Recall is similarity. Reporting is aggregation. Nothing malfunctioned — the two questions want different machines. A vector store's primitive is nearest-neighbour search: embed the query, rank stored vectors by distance, return the top-k, optionally narrowed by a metadata filter. That is the whole contract. There is no COUNT , no GROUP BY , no JOIN , no HAVING — a similarity engine ships no query planner, and even the metadata filter only narrows candidates around the approximate search, so what comes back is still a ranking of similar items, never a computed result set. "How many" has to touch every matching row . If the agent logged 4,000 memories and top-k is 20, the context the LLM sees is structurally incapable of producing the count — and an LLM doing arithmetic over a retrieved sample is a hallucination generator, not a query engine. The failure is quiet, too: the answer arrives fluent and plausible, and nothing flags that it was computed from half a percent of the data. -- "top topics this month, ranked by count" is not a similarity query. -- It's this — and it must scan every matching row, not the top-k: SELECT topic , count ( * ) AS mentions

2026-08-02 原文 →
开发者

Database Views in Your ERD: Read-Only Entities, Not Fake Tables

Disclosure: I build Schemity , a desktop ERD tool - this post is from our blog and uses it for the examples. TL;DR: Database views carry real responsibilities - reporting layers, security boundaries, API surfaces - but ERD tools either leave them out entirely (DBML has no view support despite requests since 2022) or draw them as if they were ordinary tables. Schemity displays views and materialized views as read-only entities with italic names and a bold view or mview token in the entity footer, so derived relations are distinguishable from base tables at a glance, and they can be imported into context views like any other entity. A database view belongs in your ERD, but not disguised as a table: it is a derived, read-only relation, and the diagram should say so at a glance. Schemity draws views and materialized views as read-only entities with italic names - present on the canvas, visually distinct from the base tables they are built on. That sentence would be unremarkable if the rest of the tooling world agreed with it. Mostly, it does not. In most ERD tools your views are simply absent, and in the rest they are dressed up as something they are not. The reporting layer your diagram pretends does not exist Views are not decoration. They are where schemas put their public face: the reporting layer that joins five tables into one readable relation, the security boundary that exposes a subset of columns to an application role, the compatibility shim that survives a refactor. On Supabase , views are how you shape what PostgREST exposes as an API. A materialized view may be the single most performance-critical object in an analytics schema. Whoever reads your diagram to understand the system needs to see them. Yet the diagram usually cannot show them. DBML - the schema language behind dbdiagram.io - has no syntax for views at all: a user proposed designing views with join definitions in December 2022, others were still upvoting the request in July 2024, and there has be

2026-08-02 原文 →
AI 资讯

What's new in our latest Android dependency bumps — ConstraintLayout, Firebase, Intercom, Auth0

We just bumped four dependencies in the app. Here's what each one brings. implementation 'androidx.constraintlayout:constraintlayout:2.2.2' implementation platform ( 'com.google.firebase:firebase-bom:34.17.0' ) implementation 'io.intercom.android:intercom-sdk:18.6.0' implementation 'com.auth0.android:auth0:4.0.1' ConstraintLayout 2.2.2 The library's in maintenance mode now — Google's steering everyone toward Compose for new UI — so releases here are small, focused patches. This one carries forward a binary compatibility fix in constraintlayout-core that landed in the 2.2.x line. Firebase BoM 34.17.0 The BoM pins compatible versions across every Firebase library you pull in. This release lands close behind: Firebase AI Logic (17.14.0) — new factory methods exposing thoughtSignature / isThought on response parts, plus automatic function calling for LiveGenerativeModel Authentication (24.2.0) — fixed an auth timeout on dual-stack Wi-Fi, where long IPv6 timeouts were blocking IPv4 fallback Cloud Firestore (26.4.1) — now caches documents over 1MB by chunk-reading from local SQLite; fixed a debug-logging OOM caused by large payloads Cloud Messaging (25.1.1) — fixed a re-registration bug tied to Firebase installation ID changes Crashlytics (20.1.0) — on API 37+, fatal event reports now carry OOM/anomaly context from the ProfilingManager API Firebase Installations (19.1.2) — internal storage moved from SharedPreferences to DataStore Performance Monitoring (22.0.6) — fixed _app_start traces getting incorrectly suppressed on API 34+ SQL Connect (17.3.2) — several fixes to realtime query subscriptions around auth-token refresh and expiry Intercom Android SDK 18.6.0 Pinch-to-zoom, double-tap-to-zoom, and pan on full-screen image attachments Fixed an ANR during Intercom.initialize() caused by Keystore and persisted-identity reads blocking the calling thread Fixed the keyboard covering form fields in Canvas Kit sheets — IME insets are now handled correctly Fixed a crash from a nu

2026-08-02 原文 →
AI 资讯

Row and Field-Level Data Provenance: Why It's Worth the Pain (and Where the Pain Is)

Most "data lineage" you've seen answers a schema question: table B comes from table A , or column B.total comes from columns A.price and A.qty . That's genuinely useful, and tools like OpenLineage do it well. But notice what it doesn't tell you: it says which columns can influence an output. It never says which values actually did . That gap is the whole subject of this post. I built a small, self-contained reference pipeline that captures provenance at the row and field level — "the value in this destination row, this field, was computed from these specific source (row, field) pairs" — and I want to walk through two things: why you'd ever want provenance at that granularity, and why it's genuinely hard once you commit to it. Repo (dbt-core + DuckDB, no server, no cloud, runs on a clean checkout): https://github.com/stevenblough/row-level-prov The one distinction everything follows from Here's the sentence the entire project turns on: Column-level lineage is a schema-sized, static fact you can derive from code. Value-level provenance is a data-sized, dynamic fact you must capture at execution. Put it in complexity terms and the consequences become obvious: Column lineage is O(schema) . It scales with how many columns you have. You can compute it by parsing SQL, offline, without ever looking at a single row. Value provenance is O(rows × fan-in) . It scales with your data volume times how many source values feed each output value. It does not exist anywhere until the query runs, and it can only be captured there , piggybacked on the query that actually produced the values. You cannot "reconstruct" value provenance later by re-querying the sources — the moment the source changes, you'd reconstruct a different answer than what really happened. That single exponent change ( schema → rows × fan-in ) is why value-level provenance has an entire class of problems that column lineage never faces. Why bother? The reasons for this level of granularity Granularity is expensive,

2026-07-31 原文 →
AI 资讯

TimescaleDB 2.27 Added Bloom Filters to UPDATE and DELETE. Your EXPLAIN Won't Tell You If They Work Unless You Know These Counters.

TimescaleDB 2.27, released May 12 2026, extends bloom-filter batch pruning from reads to writes. UPDATE, DELETE, and UPSERT against compressed columnstore data can now skip decompressing batches that provably cannot contain the target rows. The reported gains are real: up to 160x for selective UPDATE/DELETE, and over 2x for UPSERT. The feature is automatic. Whether it is actually firing on your workload is not something you can assume, and the only way to confirm it is to read new EXPLAIN counters that the release notes mention but do not explain. Worse, the counter names are inconsistent between the write paths, so even a careful reader ends up guessing. This post is about reading those counters correctly, and about the two things in this release that will silently break a query if you upgrade without noticing them. What is actually being skipped A quick model of the mechanism, because the counters only make sense against it. Hypercore stores compressed data in batches, roughly a thousand rows each. For columns that are not the segmentby key, TimescaleDB maintains a sparse bloom filter per batch: a small probabilistic summary that answers one question, "could this batch contain column = X ?", without touching the compressed payload. A bloom filter has a useful asymmetry. A negative is certain: if the filter says no, the value is definitely absent, and the batch can be skipped whole. A positive is not: the filter says "maybe", you decompress, and sometimes the value is not there after all. That last case is a false positive, and it is the number that tells you whether the whole scheme is paying off. Before 2.27, a DELETE ... WHERE sensor_id = 'x' against compressed data decompressed every candidate batch to check. Now the bloom filter is consulted first, and batches that cannot match are never decompressed. The work you save is the decompression of the batches that get pruned. The work you waste, when the filter is poorly matched to your data, is the bloom check on

2026-07-31 原文 →
AI 资讯

Deploying Metabase on Kubernetes

Metabase is an open-source BI tool for building charts and dashboards over MySQL, PostgreSQL, MongoDB, Redshift, and more. This guide deploys Metabase on Kubernetes, loads the Sakila sample dataset into MySQL, builds a dashboard, and secures it behind Nginx Ingress with cert-manager TLS. Prerequisites: a Kubernetes cluster with kubectl / helm configured, a Linux workstation, a reachable MySQL server, and a domain name. Load the Sakila Sample Database Sakila models a DVD rental store — films, actors, inventory, rentals. $ sudo apt install zip -y $ wget https://downloads.mysql.com/docs/sakila-db.zip $ unzip sakila-db.zip Connect to your MySQL server (replace host/port/user): $ mysql -h <HOST_ENDPOINT> -P <DATABASE_PORT> -u <ADMIN_USER> -p mysql > CREATE DATABASE sakila ; mysql > SOURCE sakila - db / sakila - schema . sql ; mysql > SOURCE sakila - db / sakila - data . sql ; Deploy Metabase $ nano metabase.yaml apiVersion : apps/v1 kind : Deployment metadata : name : metabase spec : selector : matchLabels : app : metabase replicas : 1 template : metadata : labels : app : metabase spec : containers : - name : metabase image : metabase/metabase:latest ports : - containerPort : 3000 protocol : TCP --- apiVersion : v1 kind : Service metadata : name : metabase-svc spec : type : LoadBalancer selector : app : metabase ports : - name : http port : 8080 targetPort : 3000 Your cloud provider may need a provider-specific LoadBalancer annotation here (e.g. to set the listener protocol) — check its Kubernetes docs if the default doesn't work. $ kubectl apply -f metabase.yaml $ kubectl get deployments $ kubectl get services Wait for metabase-svc to get an EXTERNAL-IP (can take a few minutes), then visit http://<external-ip>:8080 to confirm the Metabase welcome page loads. Connect Metabase to the Database Let's get started → pick language. Enter your name, email, company, and a password. Select your use case. Database engine: MySQL . Set a display name, then host/port/database/user/pa

2026-07-31 原文 →
AI 资讯

Deploying a PostgreSQL Cluster with Patroni and HAProxy on Ubuntu 24.04

A Patroni cluster needs an odd number of nodes to maintain quorum — with 3 nodes, losing 1 still leaves a majority, so the cluster keeps running. This guide builds a 3-node PostgreSQL cluster on Ubuntu 24.04 with Patroni handling replication and automatic failover, etcd as the coordination store, and HAProxy load-balancing client connections — all secured with TLS. Prerequisites: three Ubuntu 24.04 servers (2 vCPU / 4GB RAM minimum) with PostgreSQL installed, non-root sudo access, and a domain with three A records: node1.example.com , node2.example.com , node3.example.com . Replace these placeholders with your actual subdomains throughout. Install Dependencies Run on all three nodes unless noted otherwise. 1. Install packages: $ sudo apt update $ sudo apt install haproxy certbot pipx -y $ sudo pip3 install --break-system-packages 'patroni[etcd3]' psycopg2-binary psycopg 2. Install etcd: $ wget https://github.com/etcd-io/etcd/releases/download/v3.6.4/etcd-v3.6.4-linux-amd64.tar.gz $ tar -xvf etcd-v3.6.4-linux-amd64.tar.gz $ sudo mv etcd-v3.6.4-linux-amd64/etcd etcd-v3.6.4-linux-amd64/etcdctl /usr/local/bin/ 3. Open firewall ports — 80 (Certbot), 2379/2380 (etcd), 5432/5433 (PostgreSQL + Patroni-managed PostgreSQL), 8008/8009 (Patroni REST API): $ sudo ufw allow 80,2379,2380,5432,5433,8008,8009/tcp $ sudo ufw reload $ sudo ufw status Configure SSL Certificates 1. Request a certificate per node (run on each node for its own subdomain): $ sudo certbot certonly --standalone -d node1.example.com -m admin@example.com --agree-tos --no-eff 2. Create a cert-prep script on each node (set HOSTNAME to that node's subdomain): $ sudo nano /usr/local/bin/prepare-ssl-certs.sh #!/bin/bash HOSTNAME = "node1.example.com" # Update for each node CERT_DIR = "/etc/letsencrypt/live/ $HOSTNAME " ARCHIVE_DIR = "/etc/letsencrypt/archive/ $HOSTNAME " getent group ssl-users > /dev/null || sudo groupadd ssl-users for user in etcd patroni haproxy postgres ; do if ! id " $user " > /dev/null 2>&1 &&

2026-07-31 原文 →
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Manticore Search 28.6.6: UUID document IDs, ordered GROUP_CONCAT(), and 16 fixes

Manticore Search 28.6.6 has been released. The headline additions are UUID document IDs for real-time tables and ordered, limited GROUP_CONCAT() for grouped queries. The release also includes 16 fixes for backups, replication, query processing, SQL compatibility, and secondary indexes. This post covers everything shipped from 28.4.5 through 28.6.6 . Upgrade notes There are no new mandatory data migrations in this release. UUID IDs are an opt-in table definition: existing numeric-ID tables keep working as they are. If you want UUID identifiers, create a real-time table with id uuid ; ALTER TABLE cannot convert an existing table between numeric and UUID IDs. Two fixes are particularly useful for production installations. Successful backups now always unfreeze real-time tables when they finish (previously in rare cases they didn't), rather than leaving writes blocked. And authenticated replication can again add an existing populated RT table with ALTER CLUSTER ... ADD . UUID document IDs for real-time tables Applications often already have UUID identifiers from the system of record. Until now, using them with Manticore Search meant maintaining a separate numeric ID mapping. Real-time tables can now use UUID document IDs directly: CREATE TABLE products_uuid ( id uuid , title text , price int ); Manticore accepts an explicit UUID string, or generates one when id is omitted from an insert or replace. UUID equality and IN filters work in queries, and UUID IDs can be used with REPLACE , UPDATE , and DELETE . This is currently a real-time-table capability, including columnar and replicated RT tables. Plain, percolate, and sharded tables continue to use their existing ID models. Ordered and limited GROUP_CONCAT() Grouped results often need a compact preview of the most relevant values in each group. GROUP_CONCAT() can now sort values and retain only the requested number of them in explicit SQL GROUP BY queries: SELECT category , GROUP_CONCAT ( title ORDER BY price DESC SEPARA

2026-07-31 原文 →
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Why AI Agents Lose Their Memory And How MemoFS Solves It

Whether you are using off-the-shelf AI coding tools like Claude Code and Cursor or building custom autonomous AI agents with TypeScript and LLM APIs, you hit the exact same fundamental wall: AI agent amnesia . As an agent user , you spend forty-five minutes explaining your architecture, deployment quirks, and database rules. The agent writes brilliant code. You close the CLI or tab, open a new session the next morning, and the agent suggests the exact legacy library you rejected yesterday. As an agent builder , you struggle to keep your custom agentic loops focused. As multi-step agent trajectories expand, LLM token limits force context compaction, wiping out subtle rules and past decisions while escalating API costs. The intelligence is real. The amnesia is structural. Context Windows Are Working Memory, Not Long-Term Memory The AI industry’s standard reflex to agent amnesia has been pushing context windows to 1M+ tokens. But a context window is working memory (RAM), not long-term storage (disk). Relying on massive context windows introduces three critical engineering bottlenecks for both users and builders: Context Compaction Destroys Rationale : When a session reaches token limits, agents automatically compact their context history. Compaction summarizes conversations into short summaries, quietly wiping out subtle architectural constraints, edge cases, and past decisions. Context Drift & Attention Loss : LLMs struggle with needle-in-a-haystack attention degradation when context windows are stuffed with 100k+ lines of raw conversation history. Escalating API Costs & Latency : Re-sending full project transcripts on every prompt burns tokens rapidly and adds seconds of input processing delay for users while skyrocketing LLM bills for agent builders. Agents do not need larger transcripts. They need a durable, inspectable, versioned memory layer . Why Vector Databases Fall Short for Local & Workspace Agent Workflows When developers and AI engineers realize raw contex

2026-07-31 原文 →
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Intern Struggles with Unfamiliar Codebase: Mentorship and Debugging Practice Offered as Solutions

Bridging the Gap: Navigating the Chasm Between Academic Coding and Real-World Software Development The transition from academic coding to professional software development is fraught with challenges, particularly when it comes to navigating and debugging large, unfamiliar codebases. This gap, often overlooked in educational curricula, leaves new developers ill-prepared for the complexities of real-world projects. Below, we dissect the technical mechanisms involved in codebase navigation and debugging, their constraints, and the resulting instabilities, while reflecting on the disconnect between academic training and industry expectations. Mechanisms of Codebase Navigation and Debugging The process of understanding and working within a large codebase involves several interconnected mechanisms. Each plays a critical role in a developer's ability to efficiently and accurately contribute to a project. Code Navigation : Involves traversing a codebase using tools like "go to definition" to map code structure and dependencies. This mechanism relies on the developer's ability to interpret relationships between files and functions. Impact : Efficient navigation reduces time spent understanding the codebase. Internal Process : Iterative exploration of code paths. Observable Effect : Reduced time to locate relevant code segments. Code Comprehension : Analyzing existing code to infer purpose, logic, and side effects. Requires pattern recognition and logical deduction. Impact : Accurate comprehension minimizes unintended modifications. Internal Process : Mental modeling of code behavior. Observable Effect : Correct identification of code functionality. Debugging : Identifying and resolving bugs while minimizing collateral damage. Relies on isolating root causes and understanding dependencies. Impact : Effective debugging prevents regressions. Internal Process : Hypothesis testing and validation. Observable Effect : Bug resolution without introducing new issues. Documentation Ana

2026-07-31 原文 →