Profile Before You Optimise: A Five-Minute Habit
Most “slow” code is not slow where you think it is. Measure first, fix second — here is the five-minute loop, from flame graphs to the number you paste into a pull request.
khallaf
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// Category
Programming
Language features, algorithms, debugging techniques and everyday coding craft.
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4 articles
Optimistic vs pessimistic locking: how to choose
Two requests touch the same row and one update silently disappears. How version checks, SELECT FOR UPDATE and retry loops behave in production, and how to pick between them.
khallaf
Tip
Find the Slow Query Before Your Users Do
Nobody complains about a 40 ms query. Everybody complains about four hundred of them per page. Read EXPLAIN column by column, and find the N+1 before your users do.
khallaf
Tip
Reading a stack trace without panicking
A stack trace is a map, not a verdict. Read it from both ends, find the frame that is yours, and turn the message into a ten-line reproduction.
khallaf
Tip