caching – Page 5 – Türker Yıldırım

Sharded pub/sub, and the cluster that could not broadcast

Deep diveApril 25, 20229 min read

A broadcast that goes to every node on every publish. Classic pub/sub does not scale in a cluster, and 7.0 gives channels that respect slots.

Redis functions replace the Lua scripts nobody could version

Deep diveApril 12, 202210 min read

7.0 in April, and a script registry that survives a restart. EVAL with a SHA nobody can map back to source.

The N+1 that was in the authorisation layer

Deep diveApril 4, 202210 min read

A policy check that loads the model’s owner, per row. 200 queries on a page with 50 items and correct eager loading.

A stale-while-revalidate header the proxy actually honours

NoteMarch 22, 20221 min read

The directive is widely emitted and unevenly honoured, and nginx needs its own configuration rather than reading the response header. proxy_cache_lock is the piece that prevents a stampede…

A lock around a recomputation, and the requests that wait

NoteJanuary 11, 20222 min read

The simpler stampede fix is a lock, and it converts a burst of computation into a burst of waiting. Serving stale is nearly always the right branch and…

A deterministic moduleId keeps the vendor hash still

NoteNovember 11, 20212 min read

webpack 4 numbered modules in resolution order, so adding one import renumbered everything after it and changed the vendor chunk hash. Separating the runtime is the other half:…

The report that should have been a materialised view

Deep diveOctober 21, 202110 min read

MySQL has no materialised views and the report needs one anyway. A summary table, a watermark, and the backdated edit that breaks both.

ETags, and the conditional request nobody sends

NoteOctober 12, 20212 min read

An ETag costs nothing to emit and saves the response body only if clients actually send the conditional header back. The write side is where ETag earns its…

A migration that ran for four hours on a table nobody could lock

Deep diveSeptember 23, 202114 min read

An ALTER on forty million rows and a maintenance window nobody would approve. Online DDL is online until it is not.

Image optimisation is a build step, not a plugin

Deep diveSeptember 6, 202110 min read

A 4.2 MB hero image, uploaded by somebody doing their job correctly. LCP at 6.1 seconds, and a plugin that only runs on upload.