bad performance with nginx cache

[Franchoze Eric]

30.08.10, 19:40, "Igor Sysoev" <igor at sysoev.ru>:

> On Mon, Aug 30, 2010 at 02:15:29PM +0400, Franchoze Eric wrote:
>  
>  > Interesing may email got to the list, but I did not get your answer.
>  
>  Because you has not subscribed to the list. The email has been
>  bounced to me and I have added your address to the write only list.
>  
>  > > What OS do you use and how much memory do you have on the host?
>  > 
>  > Linux 2.6.32+, CentOS 5.2, 15GB of RAM. - so 3 GB of ram should be enought.
>  
>  What do
>  cat /proc/sys/fs/inode-max
>  cat /proc/sys/fs/inode-nr
>  find /var/www/cache2 | wc -l
>  show ?
>  
>  
>  

#cat /proc/sys/fs/file-max 
1646126
#cat /proc/sys/fs/inode-nr 
230866	0
#mount |grep cache2
tmpfs on /var/www/cache2 type tmpfs (rw)
#find /var/www/cache2 | wc -l
164865

Igor, I found that with my first settings (cache settings from first email) nginx god segfaults each 15 minutes at different random places. I changed invalidate period to 15 minutes,
cache time to 10 minutes, removed my ugly proxy_cache_key and limited to cache only one destination. Load avarage is rapidly decreased. No segfaults. I will do some tests to verify impact on turning on cache with high load and email results.

Got segfault in that places:
Core1:
[New process 24925]
#0  0x0000000000427c49 in ngx_http_request_handler ()
(gdb) bt
#0  0x0000000000427c49 in ngx_http_request_handler ()
#1  0x000000000041e777 in ngx_epoll_process_events ()
#2  0x0000000000417978 in ngx_process_events_and_timers ()
#3  0x000000000041d3b0 in ngx_worker_process_cycle ()
#4  0x000000000041bcf7 in ngx_spawn_process ()
#5  0x000000000041db99 in ngx_master_process_cycle ()
#6  0x00000000004044da in main ()
(gdb)


Core2:
(gdb) bt
#0  0x000000348d47bf0b in memcpy () from /lib64/libc.so.6
#1  0x0000000000408851 in ngx_vslprintf ()
#2  0x0000000000409445 in ngx_snprintf ()
#3  0x00000000004285e8 in ngx_http_log_error_handler ()
#4  0x00000000004286fc in ngx_http_log_error ()
#5  0x0000000000404a3d in ngx_log_error_core ()
#6  0x000000000040dd6a in ngx_connection_error ()
#7  0x000000000041a681 in ngx_unix_recv ()
#8  0x000000000043840d in ngx_http_upstream_process_header ()
#9  0x00000000004368e2 in ngx_http_upstream_handler ()
#10 0x000000000041e716 in ngx_epoll_process_events ()
#11 0x0000000000417978 in ngx_process_events_and_timers ()
#12 0x000000000041d3b0 in ngx_worker_process_cycle ()
#13 0x000000000041bcf7 in ngx_spawn_process ()
#14 0x000000000041db99 in ngx_master_process_cycle ()
#15 0x00000000004044da in main ()
(gdb)

Core3:
(gdb) bt
#0  0x000000348d430265 in raise () from /lib64/libc.so.6
#1  0x000000348d431d10 in abort () from /lib64/libc.so.6
#2  0x000000348d46a84b in __libc_message () from /lib64/libc.so.6
#3  0x000000348d4722ef in _int_free () from /lib64/libc.so.6
#4  0x000000348d47273b in free () from /lib64/libc.so.6
#5  0x0000000000405038 in ngx_destroy_pool ()
#6  0x0000000000427e8a in ngx_http_close_connection ()
#7  0x0000000000428bf7 in ngx_http_keepalive_handler ()
#8  0x0000000000417a99 in ngx_event_expire_timers ()
#9  0x00000000004179c5 in ngx_process_events_and_timers ()
#10 0x000000000041d3b0 in ngx_worker_process_cycle ()
#11 0x000000000041bcf7 in ngx_spawn_process ()
#12 0x000000000041ca49 in ngx_start_worker_processes ()
#13 0x000000000041d914 in ngx_master_process_cycle ()
#14 0x00000000004044da in main ()
(gdb)

Core4:
(gdb) bt
#0  0x000000000043bf23 in ngx_http_range_body_filter ()
#1  0x0000000000421e89 in ngx_http_output_filter ()
#2  0x0000000000437270 in ngx_http_upstream_process_non_buffered_request ()
#3  0x000000000043754a in ngx_http_upstream_process_non_buffered_upstream ()
#4  0x00000000004368e2 in ngx_http_upstream_handler ()
#5  0x000000000041e716 in ngx_epoll_process_events ()
#6  0x0000000000417978 in ngx_process_events_and_timers ()
#7  0x000000000041d3b0 in ngx_worker_process_cycle ()
#8  0x000000000041bcf7 in ngx_spawn_process ()
#9  0x000000000041ca49 in ngx_start_worker_processes ()
#10 0x000000000041d914 in ngx_master_process_cycle ()
#11 0x00000000004044da in main ()
(gdb)