FastCGI cache file has too long header

[Maxim Dounin]

Hello!

On Thu, Dec 13, 2018 at 11:17:03AM +0200, Palvelin Postmaster via nginx wrote:

> Hi,
> 
> I run nginx/1.14.0 (Ubuntu 18.04) and PHP-FPM 7.2. I get such occasional (daily) errors about too long cache file headers:
> 
> 2018/12/13 10:39:49 [crit] 1537#1537: *760972 cache file "/var/lib/nginx/fastcgi/mydomain-fi/d/be/7a11ac32c28dc9f8c3d7da12fe3d6bed" has too long header, client: XXX.XXX.XXX.XXX, server: mydomain.fi, request: "GET /kotitreeni/ HTTP/1.1", host: ”mydomain.fi"
> 
> Can someone offer any insight as to why this is happening, what I could do to prevent it or how I could further analyze the cause?
> 
> Here are a couple examples of headers from such cache files _after_ the error log entry (possibly redundant, but anyhow):
> 
> 
> 

> Expires: Thu, 13 Dec 2018 09:39:31 GMT
> Pragma: public
> Cache-Control: max-age=3582, public
> ETag: "a652b989092efd137f04e13cad4af4b3"
> X-Powered-By: W3 Total Cache/0.9.7
> Content-Encoding: gzip
> Vary: Accept-Encoding
> 
> 
> 
> 

> Expires: Thu, 13 Dec 2018 08:02:19 GMT
> Pragma: public
> Cache-Control: max-age=1696, public
> ETag: "4fca3f56d337d2057ce73a6dd5712d80"
> X-Powered-By: W3 Total Cache/0.9.7
> Content-Encoding: gzip
> Vary: Accept-Encoding

"Vary" may indicate that you are hitting the bug with multiple 
variants.  Could you please try the patch from 

http://mailman.nginx.org/pipermail/nginx-devel/2018-January/010774.html

to see if it helps?

-- 
Maxim Dounin
http://mdounin.ru/