'zero size buf in output' in error_log

[iframist]

Hi, Nginx complains about empty buffer when using empty $memc_value (set $memc_value '';)

2010/10/27 08:50:11 [alert] 5827#0: *3061 zero size buf in output t:0 r:0 f:0 ...

Solution: avoid creating new empty buffer if value length is 0:

--- src/ngx_http_memc_request.c.ORiG    2010-09-14 02:38:58.000000000 -0400
+++ src/ngx_http_memc_request.c 2010-10-27 12:34:48.000000000 -0400
@@ -177,28 +177,30 @@
     *b->last++ = CR; *b->last++ = LF;

     if (memc_value_vv) {
-        dd("copy $memc_value to the request");
-        b = ngx_calloc_buf(r->pool);
-
-        if (b == NULL) {
-            return NGX_ERROR;
-        }
-
-        b->memory = 1;
-
-        b->start = b->pos = memc_value_vv->data;
-        b->last  = b->end = b->start + memc_value_vv->len;
-
-        cl = ngx_alloc_chain_link(r->pool);
-        if (cl == NULL) {
-            return NGX_ERROR;
-        }
-
-        cl->buf = b;
-        cl->next = NULL;
-
-        *ll = cl;
-        ll = &cl->next;
+       if (memc_value_vv->len) {
+               dd("copy $memc_value to the request");
+               b = ngx_calloc_buf(r->pool);
+
+               if (b == NULL) {
+                   return NGX_ERROR;
+               }
+
+               b->memory = 1;
+
+               b->start = b->pos = memc_value_vv->data;
+               b->last  = b->end = b->start + memc_value_vv->len;
+
+               cl = ngx_alloc_chain_link(r->pool);
+               if (cl == NULL) {
+                   return NGX_ERROR;
+               }
+
+               cl->buf = b;
+               cl->next = NULL;
+
+               *ll = cl;
+               ll = &cl->next;
+       }
     } else {
         /* to preserve the r->request_body->bufs untouched */

 

[agentzh]

Already applied your patch in GitHub. Thanks!