profiling – Page 2 – Türker Yıldırım

Profiling one request in production, briefly

NoteNovember 16, 20231 min read

The slow request cannot be reproduced locally, and profiling everything in production is not an option. The trigger value has to be a secret, or anybody can make…

The bundle we split by route, and the waterfall it created

Deep diveOctober 24, 202310 min read

A 900 KB bundle, split by route, and a page that got slower. Six sequential requests before the first render.

Mutation testing for one directory, and what it found

Deep diveOctober 24, 202310 min read

94% line coverage on the pricing code, and a bug that shipped anyway. A test that called the method and asserted it did not throw.

The alert that fired for two years and meant nothing

Deep diveOctober 18, 202310 min read

Thirty-one alert rules, a channel muted by everybody, and 412 alerts in a month of which four corresponded to a real problem.

The N+1 that only appeared in production

Deep diveJuly 29, 202310 min read

An endpoint at 40 ms locally and 2.1 seconds in production. Nine hundred queries on one request, and three on the same request in a test.

Partitioning by month, and the query that scanned all of them

Deep diveJune 27, 202310 min read

A 400 million row events table and a delete that could not finish. Dropping a partition takes two seconds; getting there takes a schema change.

OpenTelemetry in PHP, and auto-instrumentation that was not

NoteJune 7, 20232 min read

The PHP SDK reached 1.0 this year and the auto-instrumentation is thinner than the equivalent in other runtimes. The gap is the whole problem — a trace that…

The two-millisecond function called forty thousand times

NoteApril 19, 20232 min read

Nothing in the profile looked slow, and one function accounted for 80 seconds of a 94-second job. Sorting a profile by self time per call finds the slow…

A container we replaced with four functions

Deep diveApril 12, 20238 min read

A package with a dependency injection container, for eleven services, spending 90 ms compiling on a request that does 12 ms of work.

EXPLAIN ANALYZE, and an estimate that was out by 40x

NoteApril 11, 20231 min read

The optimiser chose a plan based on an estimate of 200 rows where the real answer was 8,000, and only the actual execution shows the difference. The gap…