load-testing – Türker Yıldırım

Load testing before a launch, again, and the same finding

NoteJanuary 8, 20251 min read

A second launch, a second load test, and the same class of finding as last year for a different reason. Two years, two resource limits, both of them…

Load testing one endpoint before a launch

NoteFebruary 2, 20232 min read

A full load test of a system is a project; a load test of the one endpoint a campaign will hit is an afternoon. The mismatch between the…

A cache invalidation bug that only appeared under load

Deep diveOctober 17, 202210 min read

Correct in every test, wrong for about one request in four thousand. A read that races a write, and a cache that keeps the loser.

A load test with an assertion is a test; without one it is a benchmark

NoteMay 26, 20222 min read

A load test that reports numbers requires somebody to interpret them; one that asserts a threshold fails a build. The ramp shape matters as much as the target:…

Profiling before you optimise

Deep diveNovember 5, 202010 min read

Two days spent optimising a function that was 3% of the request. The profiler said so in ninety seconds, and nobody had run it.

An SLO is a number somebody agreed to

Deep diveMay 20, 202014 min read

Everyone wanted the site to be fast and nobody could say what fast meant. An indicator, an objective and a window — and the error budget is what…

Lazy loading arrived in the browser

Deep diveApril 13, 20209 min read

One attribute replaces an IntersectionObserver and a library — and applying it to everything makes the Largest Contentful Paint worse rather than better.

Load testing with think time, or the number is fiction

NoteJuly 11, 20191 min read

A tool firing requests as fast as it can with no pause measures how quickly the server can be saturated, which corresponds to no real number of users.…

A cache that survives the thing it is caching

Deep diveMay 8, 201914 min read

The cache expired at noon and the database fell over at 12:00:01. A lock, a two-tier expiry, jittered TTLs, and versioned keys — in that order of importance.

Load testing with a think time, or the numbers are fiction

NoteFebruary 16, 20181 min read

A tool firing requests as fast as it can with no pause measures how fast the server can be saturated, which is not a number that corresponds to…