--- title: "Async Logging Is Not a Silver Bullet — What Actually Limits Performance" url: https://daily.dev/posts/async-logging-is-not-a-silver-bullet-what-actually-limits-performance-h14m0a8he source_url: https://faun.pub/async-logging-is-not-a-silver-bullet-what-actually-limits-performance-90cd45f23c7b type: article source: "Faun" published: 2026-04-12T18:17:10.750Z updated: 2026-04-12T18:17:36.575Z tags: ["performance", "logging", "c++"] reading_time: 6 upvotes: 24 comments: 2 language: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Async Logging Is Not a Silver Bullet — What Actually Limits Performance **[Faun](https://daily.dev/sources/faun)** · 6 min read · 24 upvotes · 2 comments ## Summary Async logging is commonly assumed to make logging cheaper, but it only redistributes the cost rather than eliminating it. The real pipeline includes a capture step (copying or serializing data) before enqueuing, which is required for correctness due to data lifetime issues with deferred formatting. Formatting often dominates logging cost, and moving it to a background thread doesn't make it faster. A single backend thread creates a hard throughput ceiling, and queues only delay when overload becomes visible. An alternative approach — optimizing formatting on the caller thread and only offloading I/O asynchronously — avoids lifetime issues, reduces copying, and produces more predictable behavior. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Community discussion Top comments from developers on daily.dev. **@gaburayondev** · 0 upvotes > Async logging is one of those optimisations that feels obviously right until you trace where the work actually goes — and this post does the rare thing of following the cost all the way through the pipeline instead of stopping at the queue. The key insight is that moving work to a background thread changes *who* pays the cost, not whether the cost exists; a single backend thread is still a bottleneck, just one that reveals itself later and less predictably. Optimising formatting on the caller thread and offloading only I/O is the kind of counterintuitive conclusion that only lands when you... ## Similar posts on daily.dev - [Why You Should Tune Code Before Your Garbage Collector](https://daily.dev/posts/why-you-should-tune-code-before-your-garbage-collector-7dmf5pz8z) · Hacker News · 1 upvotes · 0 comments - [How to Reduce Log Data Costs Without Losing Important Signals](https://daily.dev/posts/how-to-reduce-log-data-costs-without-losing-important-signals-cgdw8bnaj) · Last9 · 0 upvotes · 0 comments --- Tags: [#performance](https://daily.dev/tags/performance), [#logging](https://daily.dev/tags/logging), [#c++](https://daily.dev/tags/c++) [View this post on daily.dev](https://daily.dev/posts/async-logging-is-not-a-silver-bullet-what-actually-limits-performance-h14m0a8he)