Performance
The Bundle That Shipped the Whole Library for One Function
One import pulled the entire package into the client bundle, and the tree shaker could not help, because the import went through the barrel file, and the…
Code Review
Reviewing the N+1 Query Hidden Inside a Serializer
The list endpoint issued one query for the rows and one per row for the relation, and the extra queries were invisible in the view because the serializer…
Performance
The Four Megabyte Hero Image the CMS Never Resized
The upload was stored once at full size and served as-is to every device, so the largest element on the page was also the slowest, and it blocked the render…
Tooling
Reading EXPLAIN ANALYZE Like a Map Rather Than a Wall
The plan output looked like noise until the nested loops were read as a route and the row estimate gap pointed straight at the missing statistic, and the…
Deep Dive
Why the TLS Handshake Cost Three Round Trips and How to Lose Two
The first request paid for DNS, the TCP connect and a full TLS 1.2 negotiation before a single byte of the response arrived, and the round trips were the…
Performance
The Batch Job That Paid Full Price for One Call at a Time
The nightly job sent each record separately with the same system prompt, so the shared prefix was billed eight thousand times instead of once, and the bill…
Deep Dive
Why LLM Latency Is Bimodal and the Average Hides It
The response times split into a fast cluster and a slow cluster, and the mean landed in the empty space between them, describing a latency that no request…
Performance
The Context Stuffing That Inflated Time to First Token
Every retrieved document went into every prompt because retrieval was cheap, and the prefill cost of the context nobody read became the latency users waited…
Bug Hunt
The Model-Written Regex That Took Nine Minutes on One Input
The generated pattern passed every test in the suite, then a single long string made it run for nine minutes. The pattern was not wrong.
Performance
The Re Render Cascade From a Context That Changes Every Tick
A context value rebuilt on every render made every consumer re render on every tick, and the consumers included the provider's own parent, so the cascade…
Tooling
pg_stat_statements Is the Query Ledger You Never Opened
The extension records every query's call count, total time and rows, normalised by shape, and the slow query you chase for a week is one aggregation away…
Deep Dive
How the Libuv Threadpool Starves Your DNS Lookups
Node's DNS and file system work share a threadpool of four threads by default, and one slow file read queues every lookup behind it, so the event loop is…