Türker Yıldırım

performance

  • Import maps, and a page with no bundler

    Note1 min read

    Bare module specifiers resolved by the browser, which removes the last reason a small page needs a bundler. The import map is generated by the same script that…

  • A partition drop that finally ran

    Note1 min read

    A partitioning scheme built in 2023 for a retention policy that nobody had authority to enforce until this year. Dropping one partition a day rather than all of…

  • The job that ran on every push and needed to run on none

    Note2 min read

    A workflow job building documentation on every push to every branch, publishing nothing except on the default branch. A conditional inside a job means the job still starts,…

  • A build with no bundler

    Deep dive9 min read

    A site with 18 KB of JavaScript and a build pipeline sized for something larger. What a bundler provides, listed, and which of it is needed.

  • The query that runs four million times and takes two milliseconds

    Note2 min read

    A query fast enough to never appear in a slow log, accounting for a fifth of all database time. A slow query log has a threshold and a…

  • A query plan that was different for one customer

    Note2 min read

    The same query, the same index, and a different execution plan depending on which customer it is run for. The optimiser switching strategies at a selectivity threshold is…

  • An assertion on a query count that finally broke

    Note2 min read

    A test asserting fewer than ten queries, written in 2023, failing in July because a legitimate feature added an eleventh. A bound that fails on a legitimate change…

  • Percentiles labelled by consumer, and the outlier

    Note1 min read

    One label on a histogram, and a p95 that had been describing nobody. An aggregate percentile is a weighted average of populations that may have nothing in common,…

  • Two years of query logs, read once

    Deep dive10 min read

    A slow query log rotating for two years and never aggregated, and performance work driven by whoever complained loudest.

  • The endpoint that was slow for one customer

    Deep dive9 min read

    A healthy p95 and one customer for whom the endpoint takes four seconds. An aggregate metric that averages away the only case that matters.