Reduce default API server workers to 1 #55707
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Change the default number of API server workers from 4 to 1 and add guidance to deploy multiple API servers for scaling instead of increasing workers per server. With FastAPI, sync code runs in an external thread pool, making multiple workers within a single api server less necessary than it was in our flask days. And with uvicorns new spawn behavior instead of fork, it means no shared copy-on-write memory between workers, so it's better to scale horizontally now.
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vatsrahul1001
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Sep 16, 2025
vatsrahul1001
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Sep 16, 2025
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I should say, I think this is a safer default and (in my testing at least) avoids the timeout problems we've seen in #52270 even in a cpu constrained environment. My scale testing shows this change is roughly equivalent with 1 core, and a lot faster with half a core (especially for heavier requests). |
pierrejeambrun
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Sep 16, 2025
kaxil
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Sep 16, 2025
vincbeck
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Sep 16, 2025
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Sep 16, 2025
Change the default number of API server workers from 4 to 1 and add guidance to deploy multiple API servers for scaling instead of increasing workers per server. With FastAPI, sync code runs in an external thread pool, making multiple workers within a single api server less necessary than it was in our flask days. And with uvicorns new spawn behavior instead of fork, it means no shared copy-on-write memory between workers, so it's better to scale horizontally now. (cherry picked from commit 87fc469)
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Sep 17, 2025
Change the default number of API server workers from 4 to 1 and add guidance to deploy multiple API servers for scaling instead of increasing workers per server. With FastAPI, sync code runs in an external thread pool, making multiple workers within a single api server less necessary than it was in our flask days. And with uvicorns new spawn behavior instead of fork, it means no shared copy-on-write memory between workers, so it's better to scale horizontally now.
dstandish
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Sep 19, 2025
Change the default number of API server workers from 4 to 1 and add guidance to deploy multiple API servers for scaling instead of increasing workers per server. With FastAPI, sync code runs in an external thread pool, making multiple workers within a single api server less necessary than it was in our flask days. And with uvicorns new spawn behavior instead of fork, it means no shared copy-on-write memory between workers, so it's better to scale horizontally now. (cherry picked from commit 87fc469)
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Sep 30, 2025
Change the default number of API server workers from 4 to 1 and add guidance to deploy multiple API servers for scaling instead of increasing workers per server. With FastAPI, sync code runs in an external thread pool, making multiple workers within a single api server less necessary than it was in our flask days. And with uvicorns new spawn behavior instead of fork, it means no shared copy-on-write memory between workers, so it's better to scale horizontally now.
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Change the default number of API server workers from 4 to 1 and add guidance to deploy multiple API servers for scaling instead of increasing workers per server. With FastAPI, sync code runs in an external thread pool, making multiple workers within a single api server less necessary than it was in our flask days. And with uvicorns new spawn behavior instead of fork, it means no shared copy-on-write memory between workers, so it's better to scale horizontally now.
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Change the default number of API server workers from 4 to 1 and add guidance to deploy multiple API servers for scaling instead of increasing workers per server. With FastAPI, sync code runs in an external thread pool, making multiple workers within a single api server less necessary than it was in our flask days. And with uvicorns new spawn behavior instead of fork, it means no shared copy-on-write memory between workers, so it's better to scale horizontally now.
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Change the default number of API server workers from 4 to 1 and add guidance to deploy multiple API servers for scaling instead of increasing workers per server. With FastAPI, sync code runs in an external thread pool, making multiple workers within a single api server less necessary than it was in our flask days. And with uvicorns new spawn behavior instead of fork, it means no shared copy-on-write memory between workers, so it's better to scale horizontally now.
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Change the default number of API server workers from 4 to 1 and add guidance to deploy multiple API servers for scaling instead of increasing workers per server. With FastAPI, sync code runs in an external thread pool, making multiple workers within a single api server less necessary than it was in our flask days. And with uvicorns new spawn behavior instead of fork, it means no shared copy-on-write memory between workers, so it's better to scale horizontally now.
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Change the default number of API server workers from 4 to 1 and add guidance to deploy multiple API servers for scaling instead of increasing workers per server. With FastAPI, sync code runs in an external thread pool, making multiple workers within a single api server less necessary than it was in our flask days. And with uvicorns new spawn behavior instead of fork, it means no shared copy-on-write memory between workers, so it's better to scale horizontally now.
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Change the default number of API server workers from 4 to 1 and add guidance to deploy multiple API servers for scaling instead of increasing workers per server. With FastAPI, sync code runs in an external thread pool, making multiple workers within a single api server less necessary than it was in our flask days. And with uvicorns new spawn behavior instead of fork, it means no shared copy-on-write memory between workers, so it's better to scale horizontally now.
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Change the default number of API server workers from 4 to 1 and add guidance to deploy multiple API servers for scaling instead of increasing workers per server. With FastAPI, sync code runs in an external thread pool, making multiple workers within a single api server less necessary than it was in our flask days. And with uvicorns new spawn behavior instead of fork, it means no shared copy-on-write memory between workers, so it's better to scale horizontally now.
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Change the default number of API server workers from 4 to 1 and add guidance to deploy multiple API servers for scaling instead of increasing workers per server. With FastAPI, sync code runs in an external thread pool, making multiple workers within a single api server less necessary than it was in our flask days. And with uvicorns new spawn behavior instead of fork, it means no shared copy-on-write memory between workers, so it's better to scale horizontally now.
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Change the default number of API server workers from 4 to 1 and add guidance to deploy multiple API servers for scaling instead of increasing workers per server. With FastAPI, sync code runs in an external thread pool, making multiple workers within a single api server less necessary than it was in our flask days. And with uvicorns new spawn behavior instead of fork, it means no shared copy-on-write memory between workers, so it's better to scale horizontally now.
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Change the default number of API server workers from 4 to 1 and add guidance to deploy multiple API servers for scaling instead of increasing workers per server. With FastAPI, sync code runs in an external thread pool, making multiple workers within a single api server less necessary than it was in our flask days. And with uvicorns new spawn behavior instead of fork, it means no shared copy-on-write memory between workers, so it's better to scale horizontally now.
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Change the default number of API server workers from 4 to 1 and add guidance to deploy multiple API servers for scaling instead of increasing workers per server. With FastAPI, sync code runs in an external thread pool, making multiple workers within a single api server less necessary than it was in our flask days. And with uvicorns new spawn behavior instead of fork, it means no shared copy-on-write memory between workers, so it's better to scale horizontally now.
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Change the default number of API server workers from 4 to 1 and add guidance to deploy multiple API servers for scaling instead of increasing workers per server. With FastAPI, sync code runs in an external thread pool, making multiple workers within a single api server less necessary than it was in our flask days. And with uvicorns new spawn behavior instead of fork, it means no shared copy-on-write memory between workers, so it's better to scale horizontally now.
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Change the default number of API server workers from 4 to 1 and add guidance to deploy multiple API servers for scaling instead of increasing workers per server. With FastAPI, sync code runs in an external thread pool, making multiple workers within a single api server less necessary than it was in our flask days. And with uvicorns new spawn behavior instead of fork, it means no shared copy-on-write memory between workers, so it's better to scale horizontally now.
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Change the default number of API server workers from 4 to 1 and add guidance to deploy multiple API servers for scaling instead of increasing workers per server. With FastAPI, sync code runs in an external thread pool, making multiple workers within a single api server less necessary than it was in our flask days. And with uvicorns new spawn behavior instead of fork, it means no shared copy-on-write memory between workers, so it's better to scale horizontally now.
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Change the default number of API server workers from 4 to 1 and add guidance to deploy multiple API servers for scaling instead of increasing workers per server. With FastAPI, sync code runs in an external thread pool, making multiple workers within a single api server less necessary than it was in our flask days. And with uvicorns new spawn behavior instead of fork, it means no shared copy-on-write memory between workers, so it's better to scale horizontally now.
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Change the default number of API server workers from 4 to 1 and add guidance to deploy multiple API servers for scaling instead of increasing workers per server. With FastAPI, sync code runs in an external thread pool, making multiple workers within a single api server less necessary than it was in our flask days. And with uvicorns new spawn behavior instead of fork, it means no shared copy-on-write memory between workers, so it's better to scale horizontally now.
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Change the default number of API server workers from 4 to 1 and add guidance to deploy multiple API servers for scaling instead of increasing workers per server.
With FastAPI, sync code runs in an external thread pool, making multiple workers within a single api server less necessary than it was in our flask days. And with uvicorns new spawn behavior instead of fork, it means no shared copy-on-write memory between workers, so it's better to scale horizontally now.
Closes #52270