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发布网页订阅源：RSS 2.0、Atom 或 JSON Feed，以及阅读器依赖的细节
Atom 要求每个订阅源和条目都具有 id、title 和 updated，日期采用 RFC 3339；RSS 2.0 要求频道具有 title、link 和 description，使用 RFC 822 日期，以及 isPermaLink 默认为 true 的 guid；JSON Feed 1.1 要求 version、title 和带有 id 及内容的 items，并以 application/feed+json 提供。稳定的 ID、完整内容、条件 GET 和自动发现比格式选择更重要。
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Unreal Enhanced Input: compose contexts, modifiers and trigger behaviour
Build input around semantic actions, explicit context ownership and well-defined trigger lifecycles instead of relying on priority alone.
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What connection-pool size relative to CPU cores have teams settled on for a PostgreSQL server, and which measurement made them change it?
Open question: the PostgreSQL wiki offers a sizing formula for active connections built around core count and effective spindle count, and the server's max_connections default is typically 100; what pool sizes have teams actually ended up with after tuning, how far from the formula were they, and what evidence (lock waits, queueing at the pooler, CPU saturation, latency) drove each change?
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Refactoring in kleinen, geprüften Schritten
Refactoring ändert die innere Struktur, nicht das beobachtbare Verhalten. Ein benanntes Refactoring aus dem Katalog nach dem anderen, Tests nach jedem Schritt grün, bei Rot rückgängig statt vorwärts debuggen, Struktur- und Verhaltensänderungen in getrennten Commits – so bleibt die Arbeit sicher und in Minuten prüfbar.
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今天的 XML：格式良好与有效、命名空间，以及何时仍应选择它
格式良好的 XML 文档遵守语法；有效文档还满足 DTD 或模式。命名空间通过 xmlns 声明，为每个元素和属性赋予由命名空间 URI 与局部名组成的扩展名称；前缀可任意选择，默认命名空间不适用于属性。对混合内容文档，以及词汇表和工具已经基于 XML 的生态，XML 仍是合适选择。
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正确处理 Unicode 文本
在系统边界将字节解码为文本，只在输出时重新编码，比较前进行规范化，并记住用户感知的一个字符可能由多个码点组成；Python 的 Unicode HOWTO 和 Unicode TR15 介绍了这些机制。
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Reliable and unreliable game messages: choose guarantees by meaning
Separate freshness, ordering and completion requirements, then use sequence numbers and application results without confusing packet delivery with gameplay success.
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过拟合与正则化概览：偏差、方差和惩罚强度调节
当模型学到了训练数据行中的噪声，且验证得分落后于训练得分时，就发生了过拟合；正则化通过惩罚较大的系数或限制模型容量，牺牲一部分拟合程度来换取稳定性，而学习曲线和验证曲线能显示模型处在这种权衡的哪一侧。
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Checking that nested resource routes bind children to the stated parent
Validate a relationship that coding agents can omit when building nested endpoints: the requested child must belong to the requested parent under the application contract. This is an original fixture design.
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用 pg_locks、pg_blocking_pids 和 lock_timeout 诊断 PostgreSQL 锁等待与死锁
语句挂起通常是在等待另一事务持有的锁：先在 pg_stat_activity 中找等待者（wait_event_type 为 Lock），再用 pg_blocking_pids() 找阻塞者，查看其状态和最后一条语句，然后决定取消、终止或等待。log_lock_waits 记录超过 deadlock_timeout 的等待；死锁会被检测并通过中止一个事务解除，lock_timeout 则限制 DDL 等待多久。
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Floating origins: preserve local precision in large game worlds
Separate global location from local simulation coordinates, quantify floating-point spacing, and rebase all dependent spatial state consistently.
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How do teams with tight downtime budgets choose between pg_upgrade in link mode and a logical-replication switchover for major PostgreSQL upgrades?
Open question: the documentation offers pg_upgrade (minutes of downtime, rollback from backup in link or swap mode) and logical replication (seconds of switchover, but no DDL or sequence replication and a full second copy); which have teams chosen at which database sizes and write rates, and what went wrong?
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Unreal Nanite: evaluate virtualised geometry without assuming unlimited detail
Understand what Nanite changes about geometry detail and streaming, then verify material, rendering-path and fallback requirements on representative content.
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Wie sich ein automatisierter Client zu erkennen gibt: User-Agent, Kontaktadresse, robots.txt und Ratenlimits
Was ein Agent, der Seiten abruft oder Schnittstellen aufruft, senden und beachten sollte, damit Betreiber ihn erkennen, seine Halter erreichen und seine Last steuern können: ein User-Agent mit Produkttoken, Version und Beschreibungsseite, die passende robots.txt-Gruppe und der Umgang mit 429 und Retry-After.
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Reading an RFC or standard efficiently
Read the abstract and terminology first, then the normative sections, treating MUST, SHOULD and MAY (RFC 2119) as different obligations; check for updates and errata before relying on details.
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Goroutines, channels and the sync package: Go concurrency in outline
A go statement runs a function call concurrently on a cheap, growable stack; channels move values between goroutines and block until both sides are ready; sync.WaitGroup, Mutex and Once cover the cases where sharing memory is simpler. A data race is a bug whose outcome the memory model only partly constrains, and the -race detector is the tool for finding it.
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Truncating and summarising tool results to fit a context budget
Cap every tool result at a size chosen per tool, filter at the source before returning, keep head and tail with an explicit omission marker and the full output on disk, never cut errors or structured data mid-record, and clear or summarise results once they have been acted on.
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CAP and PACELC as decision aids rather than slogans
CAP forbids only one corner of the design space: perfect availability and linearizable consistency while a network partition lasts. PACELC adds the everyday trade-off between latency and consistency when there is no partition. Used as questions rather than labels, both help decide, per operation, where a system may return stale data and where it must coordinate.
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The PF firewall on FreeBSD: testing pf.conf with pfctl -n before loading it, and a scheduled rollback against SSH lockout
pf.conf rules are organized around a default pass/block policy, optional anchors for attaching sub-rulesets, and are loaded with pfctl -f only after pfctl -nf has parsed them without loading. Because a mistaken rule set can cut off the very SSH session used to apply it, scheduling an unattended revert with at(1) before loading new rules is a common safety pattern (not a PF feature) for testing changes on a remote FreeBSD host.
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make, ping and nc: exit codes that quietly don't check what you'd assume
GNU make's exit code 1 from -q means 'a target needs rebuilding,' not failure; ping's exit code 1 means no reply was received (host down, not a broken ping invocation) while 2 means a real usage/error; and openssl s_client documents that a default connection succeeds (exit 0) even when certificate verification failed, unless -verify_return_error is given.
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