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I Spent 20+ Years in Industrial Maintenance. Now I’m Learning to Build Software.

I spent over 20 years working in industrial maintenance as a boilermaker. Most of that time was in refinery shutdowns and turnarounds—high-pressure environments where systems either hold or fail. There is no “mostly working” in that world. That experience has shaped how I approach software development. ⸻ I’m not just “learning to code.” I’m building systems. I’m currently working on transitioning into web development, but I’m not approaching it as a tutorial exercise I’m building real projects from day one—and documenting the process as I go. Not theory. Not exercises. Actual systems that are meant to run. ⸻ What I’m building right now A portfolio site that behaves like a system (kmwebdev.me) This isn’t a “personal website” in the usual sense. It’s a live system under controlled change. I treat it like industrial maintenance work: versioned updates instead of redesigns small, controlled changes only tracking what changed and why stability over aesthetics Nothing gets changed without intent. ⸻ A production-focused email framework (Skeleton Framework) Alongside the portfolio work, I’m building a separate system for HTML email development. Email is one of the most constrained environments in web development. Rendering is inconsistent, standards are partial, and modern CSS support is unreliable across many clients. So instead of fighting those constraints, I’m building a framework specifically designed around them. The focus is simple: predictable rendering in real-world email clients It’s still early, but it’s being developed with production use in mind—not experimentation. ⸻ The way I work hasn’t changed—only the tools have In industrial maintenance, you learn a few hard rules: don’t assume—verify don’t scale chaos don’t change more than you can test document everything that matters So I carry that directly into development: versioned releases (v1.0, v1.3.6, etc.) controlled incremental changes explicit documentation of limitations real-world testing across environmen

2026-07-04 原文 →
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Weaponizing Silence: How to Disappear While Staying Connected

Everyone is talking. Almost no one is thinking. Your morning starts with a vibration, then another, then a pile-on. Slack wants a status update. Instagram wants your face. A group chat you muted in March has resurrected itself to debate brunch. By 9:07 am you have done the emotional labor of a small call center and you have not finished your coffee. We call this being connected. A more honest word is being farmed. The internet does not pay you for your best ideas. It pays you for your fastest replies. Availability became a virtue, then a job description, then a personality. Silence got rebranded as flaking. I decided to rebrand it back, but with better tools. Not the aesthetic digital detox where you post a grainy photo of trees with “offline” in lowercase and then lurk from a finsta. I mean real disappearance. The kind where your work still ships, your people still feel held, your money still moves, and you are simply not there to watch the conveyor belt. You do not need to quit. You need to quit performing presence. The Attention Tax Is Real, and You Are Overdrawn Every ping is a micro-withdrawal from your nervous system. You pay in focus, in mood, in the ability to finish a thought. Platforms collect the interest. Researchers at UC Irvine have been tracking this for years. After an interruption it takes roughly 23 minutes to get back to the original task. The average knowledge worker gets interrupted 80 to 90 times a day. Do the multiplication and you realize most people never actually get back. They just start new half-tasks until bedtime. We treat this like a willpower problem. It is an architecture problem. Your phone is designed to win. You will not out-discipline a trillion-dollar attention refinery. You have to change the plumbing. Silence is not doing nothing. Silence is compound interest for your brain. Ten uninterrupted minutes today becomes a finished essay next week becomes a body of work next year. The people who seem calm are not morally superior. Th

2026-07-04 原文 →
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Database Indexing and Query Optimization for Python Developers

Introduction Fixing N+1 queries with select_related / prefetch_related or selectinload (see the previous post ) gets you down to a small, sane number of queries per request. The next bottleneck is what each query costs once the table has millions of rows — and that is almost always about indexing. An index turns "scan every row" into "look it up directly." Skip it, and a query that's instant in development takes seconds once real data volume shows up in production. How Indexes Work: The B-Tree Intuition Without an index, a WHERE clause forces a sequential scan : the database reads every row and checks the condition — O(n) , cost grows linearly with table size. An index is a separate, sorted structure (almost always a B-tree ) mapping column values to row locations. Because it's sorted and balanced, finding a value is a tree walk: O(log n) . On a 10-million-row table, that's the difference between reading 10 million rows and roughly 23 tree nodes. This isn't free: Writes get slower — every INSERT / UPDATE / DELETE on an indexed column also updates the index. Storage grows — each index is a sorted copy of (part of) the data. An index trades write cost and storage for read speed. Indexing a column you rarely filter or sort on is pure cost, no benefit. Reading Query Plans: EXPLAIN ANALYZE Postgres' EXPLAIN ANALYZE shows what the planner actually did, not an estimate. Before an index , filtering orders by customer_id : EXPLAIN ANALYZE SELECT * FROM orders WHERE customer_id = 48291 ; Seq Scan on orders (cost=0.00..21453.00 rows=42 width=96) (actual time=0.021..118.442 rows=41 loops=1) Filter: (customer_id = 48291) Rows Removed by Filter: 1199959 Planning Time: 0.112 ms Execution Time: 118.471 ms Seq Scan means Postgres read all ~1.2 million rows and discarded all but 41. actual time is real elapsed time — 118ms for one lookup. After CREATE INDEX idx_orders_customer_id ON orders (customer_id); : Index Scan using idx_orders_customer_id on orders (cost=0.42..8.53 rows=42 wid

2026-07-04 原文 →
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Database Indexing and Query Optimization for Java Developers

Introduction Fixing N+1 queries (see the previous post ) gets your Hibernate app down to a handful of queries per request. The next bottleneck is what each of those queries costs once your tables have millions of rows — and that is almost always a question of indexing. An index turns "scan every row" into "look it up directly." Get the index wrong — or skip it — and a query that took 2ms in development takes 4 seconds in production once real data volume shows up. How Indexes Work: The B-Tree Intuition Without an index, a WHERE clause forces a sequential scan : the database reads every row and checks the condition. That's O(n) — cost grows linearly with table size. An index is a separate, sorted data structure (almost always a B-tree ) that maps column values to row locations. Because it's sorted and balanced, finding a value is a tree walk: O(log n) . On a 10-million-row table, that's the difference between reading 10 million rows and reading roughly 23 tree nodes. The cost is not free: Writes get slower. Every INSERT / UPDATE / DELETE on an indexed column must also update the index structure. Storage grows. Each index is a copy of (part of) the data, sorted differently. An index is a trade: you pay on every write so that specific reads become fast. Indexing a column you rarely filter or sort on is pure cost with no benefit. Reading Query Plans: EXPLAIN ANALYZE Postgres' EXPLAIN ANALYZE shows what the planner actually did — not what you hope it did. Before an index , filtering orders by customer_id : EXPLAIN ANALYZE SELECT * FROM orders WHERE customer_id = 48291 ; Seq Scan on orders (cost=0.00..21453.00 rows=42 width=96) (actual time=0.021..118.442 rows=41 loops=1) Filter: (customer_id = 48291) Rows Removed by Filter: 1199959 Planning Time: 0.112 ms Execution Time: 118.471 ms Seq Scan means Postgres read all ~1.2 million rows and threw away all but 41 of them. actual time is the real elapsed time, not an estimate — 118ms for one lookup. After CREATE INDEX idx_orders

2026-07-04 原文 →
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Testing Best Practices in Python

Introduction Python's testing tools are lightweight enough that it's easy to write a lot of tests without writing good ones. A suite that mocks every collaborator, duplicates the same assertion ten times with different inputs pasted in by hand, or chases a coverage number will pass in CI and still miss real bugs. pytest gives you fixtures, parametrize , and monkeypatch — the tools that make it just as easy to write the right tests as the wrong ones. This post covers how to use them well. Test at the Right Level: the Pyramid Not every test should look the same. The test pyramid is a rough guide to where your effort should go: Unit tests — the bulk of the suite. Pure functions and classes, no I/O, no real database. Milliseconds each. Integration tests — fewer of these. Verify the seams : does your ORM query actually produce correct SQL against a real database, does your HTTP client actually parse a real response. End-to-end tests — a handful. Cover the critical flows through the whole stack, accepting they're slower and more brittle. # Unit — pure logic, no database, no framework def test_applies_ten_percent_discount_for_orders_over_100 (): calculator = DiscountCalculator () total = calculator . apply ( order_total = 150.0 ) assert total == pytest . approx ( 135.0 ) # Integration — the seam that matters: our query against a real database import pytest @pytest.fixture def db_session ( postgres_container ): # real Postgres in a test container, not mocked with postgres_container . session () as session : yield session def test_finds_orders_placed_in_the_last_week ( db_session ): db_session . add ( Order ( id = " ord-1 " , placed_at = datetime . now ( UTC ))) db_session . commit () recent = order_repository . find_recent ( db_session , within = timedelta ( days = 7 )) assert len ( recent ) == 1 A unit suite that never touches a database runs in seconds and catches most logic bugs. A handful of integration tests catch what only shows up at the boundary — the query that's s

2026-07-04 原文 →
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