# Nginx eval with memc set command very slowly **URL:** \ **Category:** NGINX\ **Created:** [March 8, 2010, 9:30am UTC](https://www.ruby-forum.com/t/nginx-eval-with-memc-set-command-very-slowly/184764 "2010-03-08T09:30:45Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![yaoxinming](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/y/e9bcb4/32.png) [@yaoxinming](https://www.ruby-forum.com/u/yaoxinming)\ **Post date:** [March 8, 2010, 9:30am UTC](https://www.ruby-forum.com/t/nginx-eval-with-memc-set-command-very-slowly/184764/1 "2010-03-08T09:30:45Z")
when use eval with memc set(all dev by agentzh ) ,I feel the response is very slowly,but get is very quickly,below is the configue location /myset { eval &var1{ set $memc\_cmd ‘set’; set $memc\_key ‘test1’; set $memc\_flags 12345; set $memc\_exptime 24; set $memc\_value ‘my\_value’; ``` memc_pass 127.0.0.1:11211; } ``` } does any one has meet this problem,any advice is welcome thanks very much ---
**Author:** ![yaoxinming](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/y/e9bcb4/32.png) [@yaoxinming](https://www.ruby-forum.com/u/yaoxinming)\ **Post date:** [March 8, 2010, 9:44am UTC](https://www.ruby-forum.com/t/nginx-eval-with-memc-set-command-very-slowly/184764/2 "2010-03-08T09:44:13Z")
On Mon, Mar 8, 2010 at 4:30 PM, yaoxinming [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > when use eval with memc set(all dev by agentzh ) ,I feel the response is > very slowly,but get is very quickly,below is the configue Which version of ngx\_memc, ngx\_eval, and memcached are you using? And which OS? Cheers, -agentzh ---
**Author:** ![yaoxinming](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/y/e9bcb4/32.png) [@yaoxinming](https://www.ruby-forum.com/u/yaoxinming)\ **Post date:** [March 12, 2010, 4:05am UTC](https://www.ruby-forum.com/t/nginx-eval-with-memc-set-command-very-slowly/184764/3 "2010-03-12T04:05:47Z")
On Tue, Mar 9, 2010 at 10:52 AM, agentzh [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > On Mon, Mar 8, 2010 at 4:30 PM, yaoxinming [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > > when use eval with memc set(all dev by agentzh ) ,I feel the response is > > very slowly,but get is very quickly,below is the configue > > I’m guessing that it’s caused by the “201 Created” status returned by > the ngx\_memc set command. According to the source of ngx\_eval, it only > accepts “200 OK”. So in case of 201, it simply returns NGX\_DECLINED, > which _may_ produce that hang. I’ve reproduced this hang on my side and spent half of my day tracking this issue. But it looked deeper than I had expected. Using subrequests issued by echo\_location and echo\_location\_async does not trigger this hang, but “eval” does. I’m now guessing it has something to do with subrequests issued from the rewrite phase because the ngx\_echo module starts subrequests in content handlers only. I don’t have enough time to track this further for now. Will get back to this issue some time later. Sorry. Cheers, -agentzh ---
**Author:** ![yaoxinming](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/y/e9bcb4/32.png) [@yaoxinming](https://www.ruby-forum.com/u/yaoxinming)\ **Post date:** [March 12, 2010, 4:10am UTC](https://www.ruby-forum.com/t/nginx-eval-with-memc-set-command-very-slowly/184764/4 "2010-03-12T04:10:28Z")
On Fri, Mar 12, 2010 at 11:05 AM, agentzh [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > I’ve reproduced this hang on my side and spent half of my day tracking > this issue. But it looked deeper than I had expected. Forgot to mention that the “post subrequest” handler does not get called in this case. It seems ngx\_http\_upstream does not call finalize\_request. Most likely an issue in ngx\_memc’s input filters. If others can take a look at the ngx\_http\_memc\_empty\_filter\_init and ngx\_http\_memc\_empty\_filter functions in ngx\_memc below, I’ll really appreciate that: ``` http://github.com/agentzh/memc-nginx-module/blob/master/src/ngx_http_memc_response.rl ``` Thanks! -agentzh ---
**Author:** ![yaoxinming](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/y/e9bcb4/32.png) [@yaoxinming](https://www.ruby-forum.com/u/yaoxinming)\ **Post date:** [March 9, 2010, 3:53am UTC](https://www.ruby-forum.com/t/nginx-eval-with-memc-set-command-very-slowly/184764/5 "2010-03-09T03:53:01Z")
On Mon, Mar 8, 2010 at 4:30 PM, yaoxinming [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > when use eval with memc set(all dev by agentzh ) ,I feel the response is > very slowly,but get is very quickly,below is the configue I’m guessing that it’s caused by the “201 Created” status returned by the ngx\_memc set command. According to the source of ngx\_eval, it only accepts “200 OK”. So in case of 201, it simply returns NGX\_DECLINED, which _may_ produce that hang. I’m currently in the Hangzhou city and far from my laptop in Beijing. So I can’t confirm this right now. I’ll look into this and hopefully do a fix in my branch of ngx\_eval if it’s indeed the case. Thanks for the report! -agentzh ---
**Author:** ![yaoxinming](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/y/e9bcb4/32.png) [@yaoxinming](https://www.ruby-forum.com/u/yaoxinming)\ **Post date:** [April 10, 2010, 4:41pm UTC](https://www.ruby-forum.com/t/nginx-eval-with-memc-set-command-very-slowly/184764/6 "2010-04-10T16:41:29Z")
On Fri, Mar 12, 2010 at 11:09 AM, agentzh [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > On Fri, Mar 12, 2010 at 11:05 AM, agentzh [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > > I’ve reproduced this hang on my side and spent half of my day tracking > > this issue. But it looked deeper than I had expected. > > Forgot to mention that the “post subrequest” handler does not get > called in this case. It seems ngx\_http\_upstream does not call > finalize\_request. Most likely an issue in ngx\_memc’s input filters. I’ve fixed this bug in ngx\_memc v0.08: ``` http://wiki.nginx.org/NginxHttpMemcModule#v0.08 ``` ngx\_memc didn’t support subrequests in memory for memcached commands other than “get” in earlier versions. Now it’s finally fixed by setting r-\>upstream-\>buffer’s .pos and .last pointers properly in the upstream input filters. Also I’ve fixed a nasty bug in the discard\_bufs function in my fork of ngx\_eval. It used to produce random hanging or segfaults when eval\_subrequest\_in\_memory was turned off. Thanks! -agentzh