[PATCH] memcached_force_ranges for memcached upstream

[Roman Arutyunyan]

Hello,
    
On Tue, Apr 21, 2015 at 03:45:12PM +0200, Martin Mlynář wrote:
> Hello,
> 
> Dne 2015-04-21 15:39, Roman Arutyunyan napsal:
> >Hello!
> >
> >On Tue, Apr 21, 2015 at 01:37:52PM +0200, Martin Mlynář wrote:
> >># HG changeset patch
> >># User Martin Mlynář <nexus at smoula.net>
> >># Date 1429613281 -7200
> >>#      Tue Apr 21 12:48:01 2015 +0200
> >># Node ID 4cb149154501fc638596ab51031f8b3b64da2a7f
> >># Parent  1bdfceda86a99a4dc99934181d2f9e2632003ca8
> >>memcached_force_ranges for memcached upstream
> >>
> >>Allow option force_ranges for memcached upstream
> >>
> >>diff -r 1bdfceda86a9 -r 4cb149154501
> >>src/http/modules/ngx_http_memcached_module.c
> >>--- a/src/http/modules/ngx_http_memcached_module.c	Mon Apr 20 17:36:51
> >>2015 +0300
> >>+++ b/src/http/modules/ngx_http_memcached_module.c	Tue Apr 21 12:48:01
> >>2015 +0200
> >>@@ -95,6 +95,13 @@
> >>       offsetof(ngx_http_memcached_loc_conf_t, upstream.read_timeout),
> >>       NULL },
> >>
> >>+    { ngx_string("memcached_force_ranges"),
> >>+
> >>NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG,
> >>+      ngx_conf_set_flag_slot,
> >>+      NGX_HTTP_LOC_CONF_OFFSET,
> >>+      offsetof(ngx_http_memcached_loc_conf_t, upstream.force_ranges),
> >>+      NULL },
> >>+
> >>     { ngx_string("memcached_next_upstream"),
> >>NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_1MORE,
> >>       ngx_conf_set_bitmask_slot,
> >>@@ -604,6 +611,7 @@
> >>     conf->upstream.next_upstream_timeout = NGX_CONF_UNSET_MSEC;
> >>
> >>     conf->upstream.buffer_size = NGX_CONF_UNSET_SIZE;
> >>+    conf->upstream.force_ranges = NGX_CONF_UNSET;
> >>
> >>     /* the hardcoded values */
> >>     conf->upstream.cyclic_temp_file = 0;
> >>@@ -647,6 +655,9 @@
> >>     ngx_conf_merge_msec_value(conf->upstream.read_timeout,
> >>                               prev->upstream.read_timeout, 60000);
> >>
> >>+    ngx_conf_merge_value(conf->upstream.force_ranges,
> >>+                              prev->upstream.force_ranges, 0);
> >>+
> >>     ngx_conf_merge_msec_value(conf->upstream.next_upstream_timeout,
> >>                               prev->upstream.next_upstream_timeout, 0);
> >
> >It's better to enable ranges in the memcached module without any
> >directives.
> >You can find such "hardcoded values" in
> >ngx_http_memcached_create_loc_conf().
> 
> I've tried to be consistent with other modules which does it this way like:
> 
> ngx_http_proxy_module.c
> ngx_http_scgi_module.c
> ngx_http_uwsgi_module.c
> ngx_http_fastcgi_module.c
> 
> Is there any reason why memcached should be an exception? Or am I getting
> something wrong?

As you can see, the memcached module is an exception for many settings.

As for ranges, memcache backend cannot apply ranges, so nginx is the only
option.  With other upstream modules nginx tries to be consistent with the
origin server behavior.

-- 
Roman Arutyunyan