upstream sent too big header while reading response header from upstream

[Jeroen Ooms]

On Mon, Feb 10, 2014 at 5:15 AM, Maxim Dounin <mdounin at mdounin.ru> wrote:
> it is likely the cause, as the config includes the following lines:
>
>     proxy_cache_methods POST;
>     proxy_cache_key "$request_method$request_uri$request_body";
>

Yikes I was not aware that the cache key gets stored into the buffers
as well. Is this mentioned in the manual anywhere?

So we need to set proxy_buffer_size to a value greater than the sum of
client_body_buffer_size + header size? Or alternatively, is there a
way that to use a fixed length hash of the request body in the
proxy_cache_key?