diff --git a/.github/workflows/setup_env.sh b/.github/workflows/setup_env.sh
index fa724895..427fdddf 100644
--- a/.github/workflows/setup_env.sh
+++ b/.github/workflows/setup_env.sh
@@ -24,7 +24,7 @@ kong-ngx-build \
     --work $DOWNLOAD_ROOT \
     --prefix $INSTALL_ROOT \
     --openresty $OPENRESTY \
-    --kong-nginx-module ${GITHUB_BASE_REF:-$GITHUB_REF_NAME} \
+    --kong-nginx-module ${GITHUB_HEAD_REF:-$GITHUB_REF_NAME} \
     --luarocks $LUAROCKS \
     --openssl $OPENSSL \
     --debug \
diff --git a/src/ngx_http_lua_kong_var.c b/src/ngx_http_lua_kong_var.c
index aa0c14d4..ec36e5d4 100644
--- a/src/ngx_http_lua_kong_var.c
+++ b/src/ngx_http_lua_kong_var.c
@@ -18,6 +18,99 @@
 #include "ngx_http_lua_kong_common.h"
 
 
+/* default variable indexes will be loaded */
+static ngx_str_t default_vars[] = {
+    ngx_string("args"),
+    ngx_string("is_args"),
+    ngx_string("bytes_sent"),
+    ngx_string("content_type"),
+    /* ngx_string("host"), */
+
+    /* http request headers */
+    ngx_string("http_authorization"),
+    ngx_string("http_connection"),
+    ngx_string("http_host"),
+    ngx_string("http_kong_debug"),
+    ngx_string("http_proxy"),
+    ngx_string("http_proxy_connection"),
+    ngx_string("http_te"),
+    ngx_string("http_upgrade"),
+
+    /* http request headers */
+    ngx_string("http_x_forwarded_for"),
+    ngx_string("http_x_forwarded_host"),
+    ngx_string("http_x_forwarded_path"),
+    ngx_string("http_x_forwarded_port"),
+    ngx_string("http_x_forwarded_prefix"),
+    ngx_string("http_x_forwarded_proto"),
+
+    /* --with-http_ssl_module */
+#if (NGX_HTTP_SSL)
+    ngx_string("https"),
+#endif
+
+    /* --with-http_v2_module */
+#if (NGX_HTTP_V2)
+    ngx_string("http2"),
+#endif
+
+    /* --with-http_realip_module */
+#if (NGX_HTTP_REALIP)
+    ngx_string("realip_remote_addr"),
+    ngx_string("realip_remote_port"),
+#endif
+
+    /* ngx_string("remote_addr"), */
+    ngx_string("remote_port"),
+
+    /* ngx_string("request"), */
+    ngx_string("request_length"),
+    ngx_string("request_method"),
+    ngx_string("request_time"),
+    ngx_string("request_uri"),
+    ngx_string("scheme"),
+    ngx_string("server_addr"),
+    ngx_string("server_port"),
+
+/* --with-http_ssl_module */
+#if (NGX_SSL)
+    ngx_string("ssl_cipher"),
+    ngx_string("ssl_client_raw_cert"),
+    ngx_string("ssl_client_verify"),
+    ngx_string("ssl_protocol"),
+    ngx_string("ssl_server_name"),
+#endif
+
+    ngx_string("upstream_http_connection"),
+    ngx_string("upstream_http_trailer"),
+    ngx_string("upstream_http_upgrade"),
+    ngx_string("upstream_status"),
+
+    ngx_null_string
+};
+
+
+static char *
+ngx_http_lua_kong_load_default_var_indexes(ngx_conf_t *cf)
+{
+    ngx_str_t                     *var;
+    ngx_int_t                      index;
+
+    for (var = default_vars; var->len; var++) {
+        index = ngx_http_get_variable_index(cf, var);
+
+        if (index == NGX_ERROR) {
+            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
+                               "unable to mark variable \"%V\" as indexed: no memory",
+                               var);
+            return NGX_CONF_ERROR;
+        }
+    }
+
+    return NGX_CONF_OK;
+}
+
+
 char *
 ngx_http_lua_kong_load_var_index(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
 {
@@ -26,6 +119,10 @@ ngx_http_lua_kong_load_var_index(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
 
     value = cf->args->elts;
 
+    if (ngx_strcmp(value[1].data, "default") == 0) {
+        return ngx_http_lua_kong_load_default_var_indexes(cf);
+    }
+
     if (value[1].data[0] != '$') {
         ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                             "invalid variable name \"%V\"", &value[1]);
@@ -93,12 +190,18 @@ ngx_http_lua_kong_ffi_var_get_by_index(ngx_http_request_t *r, ngx_uint_t index,
 
     vv = ngx_http_get_indexed_variable(r, index);
     if (vv == NULL || vv->not_found) {
+        ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                "variable value is not found by index %d", index);
+
         return NGX_DECLINED;
     }
 
     *value = vv->data;
     *value_len = vv->len;
 
+    ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "get variable value '%v' by index %d", vv, index);
+
     return NGX_OK;
 }
 
diff --git a/t/004-indexed-var.t b/t/004-indexed-var.t
index 0510590f..0c48c658 100644
--- a/t/004-indexed-var.t
+++ b/t/004-indexed-var.t
@@ -3,7 +3,7 @@
 use Test::Nginx::Socket::Lua;
 use Cwd qw(cwd);
 
-plan tests => repeat_each() * (blocks() * 5);
+plan tests => repeat_each() * (blocks() * 5) + 2;
 
 my $pwd = cwd();
 
@@ -106,6 +106,8 @@ GET /t
 value3
 
 --- error_code: 200
+--- error_log
+get variable value 'value3' by index
 --- no_error_log
 [error]
 [crit]
@@ -145,6 +147,8 @@ GET /t
 value4_2
 
 --- error_code: 200
+--- error_log
+get variable value 'value4_2' by index
 --- no_error_log
 [error]
 [crit]
diff --git a/t/005-indexed-var-openresty-suites.t b/t/005-indexed-var-openresty-suites.t
index 392d0a62..d34e1b2b 100644
--- a/t/005-indexed-var-openresty-suites.t
+++ b/t/005-indexed-var-openresty-suites.t
@@ -9,7 +9,7 @@ use Test::Nginx::Socket::Lua;
 
 repeat_each(2);
 
-plan tests => repeat_each() * (blocks() * 2 + 9);
+plan tests => repeat_each() * (blocks() * 2 + 9 + 4);
 
 #no_diff();
 #no_long_string();
@@ -40,6 +40,8 @@ GET /test
 --- response_body
 old: 32
 new: nil
+--- error_log
+get variable value '32' by index
 
 
 
@@ -64,6 +66,8 @@ GET /test?hello=world
 --- response_body
 old: hello=world
 new: nil
+--- error_log
+get variable value 'hello=world' by index
 
 
 
@@ -164,6 +168,8 @@ invalid referer:
 --- no_error_log
 [error]
 
+--- error_log
+get variable value '' by index
 
 
 === TEST 7: false $invalid_referer variable value in Lua
@@ -195,6 +201,8 @@ invalid referer: 1
 --- no_error_log
 [error]
 
+--- error_log
+get variable value '1' by index
 
 
 === TEST 8: $proxy_host & $proxy_port & $proxy_add_x_forwarded_for
@@ -350,4 +358,4 @@ variable not changeable
 --- pipelined_requests eval
 ["GET /balancer?port=8091", "GET /balancer?port=8092"]
 --- response_body eval
-["this is backend peer 8091", "this is backend peer 8092"]
\ No newline at end of file
+["this is backend peer 8091", "this is backend peer 8092"]
diff --git a/t/006-default_indexed-var.t b/t/006-default_indexed-var.t
new file mode 100644
index 00000000..2ca6bdd1
--- /dev/null
+++ b/t/006-default_indexed-var.t
@@ -0,0 +1,413 @@
+# vim:set ft= ts=4 sw=4 et fdm=marker:
+# modified from https://github.com/openresty/lua-nginx-module/blob/master/t/045-ngx-var.t
+# with index always turned on
+use Test::Nginx::Socket::Lua;
+
+#worker_connections(1014);
+#master_process_enabled(1);
+#log_level('warn');
+
+repeat_each(2);
+
+plan tests => repeat_each() * (blocks() * 8) + 10;
+
+#no_diff();
+#no_long_string();
+#master_on();
+#workers(2);
+run_tests();
+
+__DATA__
+
+=== TEST 1: sanity: directive works well
+--- http_config
+    lua_kong_load_var_index default;
+
+--- config
+    location = /test {
+        content_by_lua_block {
+            ngx.say("ok")
+        }
+    }
+--- request
+GET /test
+--- response_body
+ok
+--- no_error_log
+[error]
+[crit]
+[alert]
+
+
+
+=== TEST 2: variable $is_args, $args
+--- http_config
+    lua_package_path "../lua-resty-core/lib/?.lua;lualib/?.lua;;";
+    lua_kong_load_var_index default;
+    init_by_lua_block {
+        require("resty.kong.var").patch_metatable()
+    }
+
+--- config
+    location = /test {
+        content_by_lua_block {
+            ngx.say("var: ", ngx.var.is_args, ngx.var.args)
+        }
+    }
+--- request
+GET /test?hello=world
+--- response_body
+var: ?hello=world
+--- error_log
+get variable value '?' by index
+get variable value 'hello=world' by index
+--- no_error_log
+[error]
+[crit]
+[alert]
+
+
+
+=== TEST 3: variable $scheme, $host, $request_uri
+--- http_config
+    lua_package_path "../lua-resty-core/lib/?.lua;lualib/?.lua;;";
+    lua_kong_load_var_index default;
+    init_by_lua_block {
+        require("resty.kong.var").patch_metatable()
+    }
+--- config
+    location = /test {
+        content_by_lua_block {
+            ngx.say(ngx.var.scheme, " ",
+                    ngx.var.host, " ",
+                    ngx.var.request_uri)
+        }
+    }
+--- request
+GET /test
+--- response_body
+http localhost /test
+--- error_log
+get variable value 'http' by index
+get variable value 'localhost' by index
+get variable value '/test' by index
+--- no_error_log
+[error]
+[crit]
+[alert]
+
+
+
+=== TEST 4: variable $http_xxx
+--- http_config
+    lua_package_path "../lua-resty-core/lib/?.lua;lualib/?.lua;;";
+    lua_kong_load_var_index default;
+    init_by_lua_block {
+        require("resty.kong.var").patch_metatable()
+    }
+--- config
+    location = /test {
+        content_by_lua_block {
+            ngx.say(ngx.var.http_authorization, " ",
+                    ngx.var.http_connection, " ",
+                    ngx.var.http_host, " ",
+                    ngx.var.http_kong_debug, " ",
+                    ngx.var.http_proxy, " ",
+                    ngx.var.http_proxy_connection, " ",
+                    ngx.var.http_te, " ",
+                    ngx.var.http_upgrade
+                    )
+        }
+    }
+--- request
+GET /test
+--- more_headers
+authorization: auth
+connection: close
+host: test.com
+kong-debug: 1
+proxy: 111
+proxy-connection: 222
+te: 333
+upgrade: 444
+--- response_body
+auth close test.com 1 111 222 333 444
+--- error_log
+get variable value 'auth' by index
+get variable value 'close' by index
+get variable value 'test.com' by index
+get variable value '1' by index
+get variable value '111' by index
+get variable value '222' by index
+get variable value '333' by index
+get variable value '444' by index
+--- no_error_log
+[error]
+[crit]
+[alert]
+
+
+
+=== TEST 5: variable $http_x_forwarded_xxx
+--- http_config
+    lua_package_path "../lua-resty-core/lib/?.lua;lualib/?.lua;;";
+    lua_kong_load_var_index default;
+    init_by_lua_block {
+        require("resty.kong.var").patch_metatable()
+    }
+--- config
+    location = /test {
+        content_by_lua_block {
+            ngx.say(ngx.var.http_x_forwarded_for, " ",
+                    ngx.var.http_x_forwarded_host, " ",
+                    ngx.var.http_x_forwarded_path, " ",
+                    ngx.var.http_x_forwarded_port, " ",
+                    ngx.var.http_x_forwarded_prefix, " ",
+                    ngx.var.http_x_forwarded_proto
+                    )
+        }
+    }
+--- request
+GET /test
+--- more_headers
+x-forwarded-for: 111
+x-forwarded-host: 222
+x-forwarded-path: 333
+x-forwarded-port: 444
+x-forwarded-prefix: 555
+x-forwarded-proto: 666
+--- response_body
+111 222 333 444 555 666
+--- error_log
+get variable value '111' by index
+get variable value '222' by index
+get variable value '333' by index
+get variable value '444' by index
+get variable value '555' by index
+get variable value '666' by index
+--- no_error_log
+[error]
+[crit]
+[alert]
+
+
+
+=== TEST 6: request variables
+--- http_config
+    lua_package_path "../lua-resty-core/lib/?.lua;lualib/?.lua;;";
+    lua_kong_load_var_index default;
+    init_by_lua_block {
+        require("resty.kong.var").patch_metatable()
+    }
+--- config
+    location = /test {
+        content_by_lua_block {
+            ngx.say(ngx.var.request_method, " ",
+                    ngx.var.request_length, " ",
+                    ngx.var.request_uri, " ",
+                    ngx.var.request_time, " ",
+                    ngx.var.server_addr, " ",
+                    ngx.var.server_port
+                    )
+        }
+    }
+--- request
+GET /test
+--- response_body
+GET 58 /test 0.000 127.0.0.1 1984
+--- error_log
+get variable value 'GET' by index
+get variable value '58' by index
+get variable value '/test' by index
+get variable value '0.000' by index
+get variable value '127.0.0.1' by index
+get variable value '1984' by index
+--- no_error_log
+[error]
+[crit]
+[alert]
+
+
+
+=== TEST 7: upstream variables
+--- http_config
+    lua_package_path "../lua-resty-core/lib/?.lua;lualib/?.lua;;";
+    lua_kong_load_var_index default;
+    init_by_lua_block {
+        require("resty.kong.var").patch_metatable()
+    }
+--- config
+    location = /test {
+        content_by_lua_block {
+            ngx.say(ngx.var.upstream_http_connection, " ",
+                    ngx.var.upstream_http_trailer, " ",
+                    ngx.var.upstream_http_upgrade, " ",
+                    ngx.var.upstream_status
+                    )
+        }
+    }
+--- request
+GET /test
+--- response_body
+nil nil nil nil
+--- error_log
+variable value is not found by index
+variable value is not found by index
+variable value is not found by index
+variable value is not found by index
+--- no_error_log
+[error]
+[crit]
+[alert]
+
+
+
+=== TEST 8: ssl/https variables
+--- http_config
+    lua_package_path "../lua-resty-core/lib/?.lua;lualib/?.lua;;";
+    lua_kong_load_var_index default;
+    init_by_lua_block {
+        require("resty.kong.var").patch_metatable()
+    }
+--- config
+    location = /test {
+        content_by_lua_block {
+            ngx.say(ngx.var.https, " ",
+                    ngx.var.ssl_cipher, " ",
+                    ngx.var.ssl_client_raw_cert, " ",
+                    ngx.var.ssl_client_verify, " ",
+                    ngx.var.ssl_protocol, " ",
+                    ngx.var.ssl_server_name
+                    )
+        }
+    }
+--- request
+GET /test
+--- response_body
+ nil nil nil nil nil
+--- error_log
+get variable value '' by index
+variable value is not found by index
+variable value is not found by index
+variable value is not found by index
+variable value is not found by index
+variable value is not found by index
+--- no_error_log
+[error]
+[crit]
+[alert]
+
+
+
+=== TEST 9: reomte variables
+--- http_config
+    lua_package_path "../lua-resty-core/lib/?.lua;lualib/?.lua;;";
+    lua_kong_load_var_index default;
+    init_by_lua_block {
+        require("resty.kong.var").patch_metatable()
+    }
+--- config
+    location = /test {
+        content_by_lua_block {
+            ngx.say(ngx.var.remote_addr, " ",
+                    ngx.var.remote_port
+                    )
+        }
+    }
+--- request
+GET /test
+--- response_body_like
+127.0.0.1 \d+$
+--- error_log
+get variable value '127.0.0.1' by index
+--- no_error_log
+[error]
+[crit]
+[alert]
+
+
+=== TEST 10: realip variables
+--- http_config
+    lua_package_path "../lua-resty-core/lib/?.lua;lualib/?.lua;;";
+    lua_kong_load_var_index default;
+    init_by_lua_block {
+        require("resty.kong.var").patch_metatable()
+    }
+    set_real_ip_from 127.0.0.1;
+    real_ip_header X-Real-IP;
+--- config
+    location = /test {
+        content_by_lua_block {
+            ngx.say(ngx.var.remote_addr, " ",
+                    ngx.var.realip_remote_addr, " ",
+                    ngx.var.realip_remote_port
+                    )
+        }
+    }
+--- request
+GET /test
+--- more_headers
+X-Real-IP: 1.2.3.4
+--- response_body_like
+^1.2.3.4 127.0.0.1 \d+$
+--- error_log
+get variable value '1.2.3.4' by index
+get variable value '127.0.0.1' by index
+--- no_error_log
+[error]
+[crit]
+[alert]
+
+
+=== TEST 11: http2 variable
+--- http_config
+    lua_package_path "../lua-resty-core/lib/?.lua;lualib/?.lua;;";
+    lua_kong_load_var_index default;
+    init_by_lua_block {
+        require("resty.kong.var").patch_metatable()
+    }
+--- config
+    location = /test {
+        content_by_lua_block {
+            ngx.say("http2:", ngx.var.http2)
+        }
+    }
+--- request
+GET /test
+--- response_body
+http2:
+--- error_log
+get variable value '' by index
+--- no_error_log
+[error]
+[crit]
+[alert]
+
+=== TEST 12: variable $content_type, $bytes_sent
+--- http_config
+    lua_package_path "../lua-resty-core/lib/?.lua;lualib/?.lua;;";
+    lua_kong_load_var_index default;
+    init_by_lua_block {
+        require("resty.kong.var").patch_metatable()
+    }
+
+--- config
+    location = /test {
+        content_by_lua_block {
+            ngx.say(ngx.var.content_type, " ",
+                    ngx.var.bytes_sent)
+        }
+    }
+--- request
+GET /test
+--- more_headers
+content-type: plain
+--- response_body
+plain 0
+--- error_log
+get variable value 'plain' by index
+get variable value '0' by index
+--- no_error_log
+[error]
+[crit]
+[alert]