(bug?)Timeout when proxy-pass 0 byte file

[Maxim Dounin]

Hello!

On Wed, Sep 30, 2009 at 10:48:27PM +0400, Maxim Dounin wrote:

> Hello!
> 
> On Wed, Sep 30, 2009 at 12:42:52PM +0400, Maxim Dounin wrote:
> 
> > On Wed, Sep 30, 2009 at 11:26:59AM +0800, tOmasEn wrote:
> 
> [...]
> 
> > > the initiall request when there isn't and cache, everything is ok. the
> > > following request to same url will wait until timeout.
> > 
> > Ok, so the problem is cache.  Thanks, I'm able to reproduce it 
> > here.  I'll take a look later today how to fix it.
> 
> Patch.

No, this patch is wrong.  Corrected patch attached.

Maxim Dounin

> 
> Maxim Dounin
> 
> > 
> > Maxim Dounin
> > 
> > [...]
> > 
> > > 
> > > On Tue, Sep 29, 2009 at 10:48 PM, Maxim Dounin <mdounin at mdounin.ru> wrote:
> > > 
> > > > Hello!
> > > >
> > > > On Tue, Sep 29, 2009 at 10:08:51PM +0800, tOmasEn wrote:
> > > >
> > > > > I been expirencing very slow page load when use nginx as frontend(with
> > > > > proxy_pass) for a while.
> > > > >
> > > > > After some test and debug, i found that it always timeout on response
> > > > > of 0 byte file.
> > > > >
> > > > > So i think there might be a bug when nginx running on proxy mode and
> > > > > serving 0 byte files. The frontend will consider there should be more
> > > > > data and wait until timeout or something like this.
> > > >
> > > > Could you please provide nginx -V output and debug log?
> > > >
> > > > Maxim Dounin
> > > >
> > > > >
> > > > > Btw. Nginx is great. Thanks
> > > > >
> > > > > tomasen
> > > > >
> > > > > --
> > > > > 从我的移动设备发送
> > > > >
> > > >
> > > >
> > 

> # HG changeset patch
> # User Maxim Dounin <mdounin at mdounin.ru>
> # Date 1254336299 -14400
> # Node ID 3a18992ceed641398ac911ad7230924ba2f28929
> # Parent  7688992d2abb6759b0a91c4b0cf86802d27cbc4a
> Cache: send correct special buffer for empty responses.
> 
> diff --git a/src/http/ngx_http_file_cache.c b/src/http/ngx_http_file_cache.c
> --- a/src/http/ngx_http_file_cache.c
> +++ b/src/http/ngx_http_file_cache.c
> @@ -798,7 +798,7 @@ ngx_http_cache_send(ngx_http_request_t *
>  
>      size = c->length - c->body_start;
>      if (size == 0) {
> -        return rc;
> +        return ngx_http_send_special(r, NGX_HTTP_LAST);
>      }
>  
>      b->file_pos = c->body_start;

-------------- next part --------------
# HG changeset patch
# User Maxim Dounin <mdounin at mdounin.ru>
# Date 1254432452 -14400
# Node ID 3d5336ab6a43f7243dd7aad3dde4f21c291009e8
# Parent  7688992d2abb6759b0a91c4b0cf86802d27cbc4a
Cache: fix sending of empty and stale reponses.

For empty cached responses last buffer wasn't sent and hence client got
timeout instead of response.

For stale non-empty responses two last buffers were sent, resulting in
duplicate final chunk if chunked encoding was used.

diff --git a/src/http/ngx_http_file_cache.c b/src/http/ngx_http_file_cache.c
--- a/src/http/ngx_http_file_cache.c
+++ b/src/http/ngx_http_file_cache.c
@@ -767,7 +767,6 @@ ngx_http_file_cache_update(ngx_http_requ
 ngx_int_t
 ngx_http_cache_send(ngx_http_request_t *r)
 {
-    off_t              size;
     ngx_int_t          rc;
     ngx_buf_t         *b;
     ngx_chain_t        out;
@@ -796,15 +795,10 @@ ngx_http_cache_send(ngx_http_request_t *
         return rc;
     }
 
-    size = c->length - c->body_start;
-    if (size == 0) {
-        return rc;
-    }
-
     b->file_pos = c->body_start;
     b->file_last = c->length;
 
-    b->in_file = size ? 1: 0;
+    b->in_file = (c->length - c->body_start) ? 1: 0;
     b->last_buf = (r == r->main) ? 1: 0;
     b->last_in_chain = 1;
 
diff --git a/src/http/ngx_http_upstream.c b/src/http/ngx_http_upstream.c
--- a/src/http/ngx_http_upstream.c
+++ b/src/http/ngx_http_upstream.c
@@ -2948,7 +2948,7 @@ ngx_http_upstream_finalize_request(ngx_h
 
     r->connection->log->action = "sending to client";
 
-    if (rc == 0) {
+    if (rc == 0 && !r->cached) {
         rc = ngx_http_send_special(r, NGX_HTTP_LAST);
     }