{
  "id": 1731697,
  "title": "Why Go's encoding/csv Burns 540MB on 5M Rows (and How I Fixed It)",
  "url": "https://urgent.news/2026/08/18/why-gos-encoding-csv-burns-540mb-on-5m-rows-and-how-i-fixed-it",
  "topic": "tech",
  "section": "Tech",
  "published": "2026-08-18T15:06:51.000Z",
  "source": {
    "name": "Dev.to",
    "slug": "dev-to",
    "url": "https://dev.to/fikrimohammad/why-gos-encodingcsv-burns-540mb-on-5m-rows-and-how-i-fixed-it-4m63"
  },
  "original_language": "en",
  "account": "Go's built-in encoding/csv package allocates memory for a new []string slice and newly allocated heap strings for every single row in a CSV file. This leads to a significant number of allocations, burning up to 540MB of memory when processing a 5M-row file. To address this issue, I created go-zerocsv, a CSV parser and writer that replaces the standard library's in-place typed scanning and a compacting 4 KB buffer. This implementation keeps memory flat at around 5 KB and has zero allocations per record on the hot path.",
  "summary": "TL;DR: Go's built-in encoding/csv.Read() allocates string slices and strings for every single row, generating 10M+ allocations and burning 540 MB on a 5M-row file. I built go-zerocsv to replace this with in-place typed scanning ( Record.Scan ) and a compacting 4 KB buffer, keeping memory flat at ~5 KB with zero allocations per record on the hot path. If you parse or write large CSV files in Go,…",
  "key_points": [
    "Go's encoding/csv allocates memory for []string slice and heap strings per row",
    "This causes significant memory usage, up to 540MB for 5M-row file",
    "go-zerocsv fixes this with in-place typed scanning and compacting buffer"
  ],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}