Buffers reuse in chunked filter. There were 2 buffers allocated on each buffer chain sent through chunked filter (one buffer for chunk size, another one for trailing CRLF, about 120 bytes in total on 32-bit platforms). This resulted in large memory consumption with long-lived requests sending many buffer chains. Usual example of problematic scenario is streaming though proxy with proxy_buffering set to off. Introduced buffers reuse reduces memory consumption in the above problematic scenario. See here for initial report: http://mailman.nginx.org/pipermail/nginx/2010-April/019814.html

ngx_addon_name=ngx_mysql

HTTP_MODULES="$HTTP_MODULES ngx_http_mysql_test_module"

HTTP_INCS="$HTTP_INCS $ngx_addon_dir"
HTTP_DEPS="$HTTP_DEPS $ngx_addon_dir/ngx_mysql.h"
#CORE_LIBS="$CORE_LIBS -lmd"

USE_SHA1=YES

NGX_ADDON_SRCS="$NGX_ADDON_SRCS $ngx_addon_dir/ngx_mysql.c"
NGX_ADDON_SRCS="$NGX_ADDON_SRCS $ngx_addon_dir/ngx_http_mysql_test.c"