Max open files

Dear all,

i am using Bind-DLZ with postgresql and i am experiencing some response problem with a number of concurrent queries above 1000 (about).
We use named pipe to connect from Bind DLZ.
I noticed that Postgresql 9.6.1 is launched with a max open files.

Could be this the problem?
How can i raise the limit?

The kernel max files is 999999
Thank you!
F

[root(at)cloud-frankfurt-dns01 pgsql]# cat /proc/5336/limits
Limit Soft Limit Hard Limit Units
Max cpu time unlimited unlimited seconds
Max file size unlimited unlimited bytes
Max data size unlimited unlimited bytes
Max stack size 8388608 unlimited bytes
Max core file size 0 unlimited bytes
Max resident set unlimited unlimited bytes
Max processes 31206 31206 processes
Max open files 1024 4096 files
Max locked memory 65536 65536 bytes
Max address space unlimited unlimited bytes
Max file locks unlimited unlimited locks
Max pending signals 31206 31206 signals
Max msgqueue size 819200 819200 bytes
Max nice priority 0 0
Max realtime priority 0 0
Max realtime timeout unlimited unlimited us