view auto/feature @ 4207:4fc91bae6f83

Better recheck of dead upstream servers. Previously nginx used to mark backend again as live as soon as fail_timeout passes (10s by default) since last failure. On the other hand, detecting dead backend takes up to 60s (proxy_connect_timeout) in typical situation "backend is down and doesn't respond to any packets". This resulted in suboptimal behaviour in the above situation (up to 23% of requests were directed to dead backend with default settings). More detailed description of the problem may be found here (in Russian): http://mailman.nginx.org/pipermail/nginx-ru/2011-August/042172.html Fix is to only allow one request after fail_timeout passes, and mark backend as "live" only if this request succeeds. Note that with new code backend will not be marked "live" unless "check" request is completed, and this may take a while in some specific workloads (e.g. streaming). This is believed to be acceptable.
author Maxim Dounin <mdounin@mdounin.ru>
date Wed, 12 Oct 2011 14:22:48 +0000
parents 0ec738f18346
children d620f497c50f
line wrap: on
line source


# Copyright (C) Igor Sysoev


echo $ngx_n "checking for $ngx_feature ...$ngx_c"

cat << END >> $NGX_AUTOCONF_ERR

----------------------------------------
checking for $ngx_feature

END

ngx_found=no

if test -n "$ngx_feature_name"; then
    ngx_have_feature=`echo $ngx_feature_name \
                   | tr abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ`
fi

if test -n "$ngx_feature_path"; then
    for ngx_temp in $ngx_feature_path; do
        ngx_feature_inc_path="$ngx_feature_inc_path -I $ngx_temp"
    done
fi

cat << END > $NGX_AUTOTEST.c

#include <sys/types.h>
$NGX_INCLUDE_UNISTD_H
$ngx_feature_incs

int main() {
    $ngx_feature_test;
    return 0;
}

END


ngx_test="$CC $CC_TEST_FLAGS $CC_AUX_FLAGS $ngx_feature_inc_path \
          -o $NGX_AUTOTEST $NGX_AUTOTEST.c $NGX_TEST_LD_OPT $ngx_feature_libs"

ngx_feature_inc_path=

eval "/bin/sh -c \"$ngx_test\" >> $NGX_AUTOCONF_ERR 2>&1"


if [ -x $NGX_AUTOTEST ]; then

    case "$ngx_feature_run" in

        yes)
            # /bin/sh is used to intercept "Killed" or "Abort trap" messages
            if /bin/sh -c $NGX_AUTOTEST >> $NGX_AUTOCONF_ERR 2>&1; then
                echo " found"
                ngx_found=yes

                if test -n "$ngx_feature_name"; then
                    have=$ngx_have_feature . auto/have
                fi

            else
                echo " found but is not working"
            fi
        ;;

        value)
            # /bin/sh is used to intercept "Killed" or "Abort trap" messages
            if /bin/sh -c $NGX_AUTOTEST >> $NGX_AUTOCONF_ERR 2>&1; then
                echo " found"
                ngx_found=yes

                cat << END >> $NGX_AUTO_CONFIG_H

#ifndef $ngx_feature_name
#define $ngx_feature_name  `$NGX_AUTOTEST`
#endif

END
            else
                echo " found but is not working"
            fi
        ;;

        bug)
            # /bin/sh is used to intercept "Killed" or "Abort trap" messages
            if /bin/sh -c $NGX_AUTOTEST >> $NGX_AUTOCONF_ERR 2>&1; then
                echo " not found"

            else
                echo " found"
                ngx_found=yes

                if test -n "$ngx_feature_name"; then
                    have=$ngx_have_feature . auto/have
                fi
            fi
        ;;

        *)
            echo " found"
            ngx_found=yes

            if test -n "$ngx_feature_name"; then
                have=$ngx_have_feature . auto/have
            fi
        ;;

    esac

else
    echo " not found"

    echo "----------"    >> $NGX_AUTOCONF_ERR
    cat $NGX_AUTOTEST.c  >> $NGX_AUTOCONF_ERR
    echo "----------"    >> $NGX_AUTOCONF_ERR
    echo $ngx_test       >> $NGX_AUTOCONF_ERR
    echo "----------"    >> $NGX_AUTOCONF_ERR
fi

rm $NGX_AUTOTEST*