# Startup time of 1000 packages – 53% slower in Julia 1.12 vs 1.10

**URL:** <https://discourse.julialang.org/t/startup-time-of-1000-packages-53-slower-in-julia-1-12-vs-1-10/128343>\
**Category:** Internals & Design\
**Tags:** performance, ttfx, latency\
**Created:** [April 23, 2025, 7:36pm UTC](https://discourse.julialang.org/t/startup-time-of-1000-packages-53-slower-in-julia-1-12-vs-1-10/128343 "2025-04-23T19:36:30Z")\
**Posts on this page:** 1\
**Showing post:** 8

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**Author:** ![roflmaostc](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/roflmaostc/32/30123_2.png) [@roflmaostc](https://discourse.julialang.org/u/roflmaostc)\
**Post date:** [April 23, 2025, 8:10pm UTC](https://discourse.julialang.org/t/startup-time-of-1000-packages-53-slower-in-julia-1-12-vs-1-10/128343/8 "2025-04-23T20:10:38Z")

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> [@Datseris](#):
>
> This triggers precompilation surprisingly frequently for reasons I never fully understood (so far I thought that once a package is precompiled it stays as such forever even if you later precompile a newer version, but I guess that’s not the case?).

Same, it seems to be very unpredictable sometimes.  
However, one reason could be that Julia only stores [10 different precompilation files for a package by default](https://docs.julialang.org/en/v1/manual/environment-variables/#env-max-num-precompile-files). In my case, I set `export JULIA_MAX_NUM_PRECOMPILE_FILES=50` to have more files stored.

Also shameless plug: I assembled PrecompileAfterUpdate.jl which avoids the unexpected precompilation after Julia updates. It crawls through your recent manifests and precompiles then whenever you want (for example after a Julia update)

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