diff --git a/kong/pdk/response.lua b/kong/pdk/response.lua
index 33564b16eab4..bb6bee29fc6b 100644
--- a/kong/pdk/response.lua
+++ b/kong/pdk/response.lua
@@ -245,7 +245,6 @@ local function new(self, major_version)
     end
 
     local header_value = ngx.header[name]
-    -- local header_value = _RESPONSE.get_headers()[name]
     if type(header_value) == "table" then
       return header_value[1]
     end
diff --git a/kong/pdk/service/request.lua b/kong/pdk/service/request.lua
index 2ee665c5462e..9c01c237bc15 100644
--- a/kong/pdk/service/request.lua
+++ b/kong/pdk/service/request.lua
@@ -653,7 +653,6 @@ local function new(self)
         error("mime must be a string", 2)
       end
       if not mime then
-        -- mime = ngx.req.get_headers()[CONTENT_TYPE]
         mime = ngx_var.http_content_type
         if not mime then
           return nil, "content type was neither explicitly given " ..
diff --git a/kong/plugins/aws-lambda/request-util.lua b/kong/plugins/aws-lambda/request-util.lua
index 053299efff24..fe59f786c983 100644
--- a/kong/plugins/aws-lambda/request-util.lua
+++ b/kong/plugins/aws-lambda/request-util.lua
@@ -294,7 +294,6 @@ local function build_request_payload(conf)
     end
 
     if conf.forward_request_body then
-      -- local content_type = kong.request.get_header("content-type")
       local content_type = ngx.var.http_content_type
       local body_raw = read_request_body(conf.skip_large_bodies)
       local body_args, err = kong.request.get_body()
diff --git a/kong/plugins/bchen-hello/handler.lua b/kong/plugins/bchen-hello/handler.lua
new file mode 100644
index 000000000000..96ac24892a94
--- /dev/null
+++ b/kong/plugins/bchen-hello/handler.lua
@@ -0,0 +1,54 @@
+-- This software is copyright Kong Inc. and its licensors.
+-- Use of the software is subject to the agreement between your organization
+-- and Kong Inc. If there is no such agreement, use is governed by and
+-- subject to the terms of the Kong Master Software License Agreement found
+-- at https://konghq.com/enterprisesoftwarelicense/.
+-- [ END OF LICENSE 0867164ffc95e54f04670b5169c09574bdbd9bba ]
+local get_header = require("kong.tools.http").get_header
+
+local MyPluginHandler = {
+    PRIORITY = 1000,
+    VERSION = "0.0.1",
+}
+
+function MyPluginHandler:access()
+  -- ngx.ctx.get_headers_patch = 0
+  local start = os.clock()
+  for i=1,10 do
+    local headers = ngx.req.get_headers()
+    -- ngx.req.set_header("foo", tostring(i))
+    -- ngx.log(ngx.WARN, "bchen access", ngx.req.get_headers()["Content-Type"])
+    -- local v = headers["Content-Type"]
+  end
+  local elapsed = (os.clock() - start)
+
+  ngx.log(ngx.WARN, "bchen access", string.format(" elapsed time: %.10f, %d\n", elapsed, 1))
+  
+  -- ngx.request.set_header("foo", "bar")
+end
+
+function MyPluginHandler:response(conf)
+  
+  -- local content_type = kong.response.get_header("Content-Type")
+  kong.response.set_header("X-BChen-Plugin", "response")
+  local headers = kong.response.get_headers()
+  local headers2 = kong.service.response.get_headers()
+  local fmt = string.format
+  local string_tools = require "kong.tools.string"
+  local replace_dashes_lower = string_tools.replace_dashes_lower
+--   ngx.log(ngx.WARN, "single: ", "multi-foo-r".." : "..tostring(kong.response.get_header("multi-foo-r")))
+
+--   for k, v in pairs(headers) do
+--     ngx.log(ngx.WARN, "resp header: ", k.." : "..tostring(v))
+--     local var = fmt("upstream_http_%s", replace_dashes_lower(k))
+--     if ngx.var[var] then
+--       ngx.log(ngx.WARN, "upstream header: ", k)
+--     end
+--   end
+--   for k, v in pairs(headers2) do
+--     ngx.log(ngx.WARN, "service header: ", k.." : "..tostring(v))
+--   end
+end
+
+
+return MyPluginHandler
diff --git a/kong/plugins/bchen-hello/schema.lua b/kong/plugins/bchen-hello/schema.lua
new file mode 100644
index 000000000000..7e5451efc722
--- /dev/null
+++ b/kong/plugins/bchen-hello/schema.lua
@@ -0,0 +1,22 @@
+-- This software is copyright Kong Inc. and its licensors.
+-- Use of the software is subject to the agreement between your organization
+-- and Kong Inc. If there is no such agreement, use is governed by and
+-- subject to the terms of the Kong Master Software License Agreement found
+-- at https://konghq.com/enterprisesoftwarelicense/.
+-- [ END OF LICENSE 0867164ffc95e54f04670b5169c09574bdbd9bba ]
+
+local PLUGIN_NAME = "bchen-hello"
+
+local schema = {
+  name = PLUGIN_NAME,
+  fields = {
+    { config = {
+        type = "record",
+        fields = {
+        },
+      },
+    },
+  },
+}
+
+return schema
diff --git a/kong/plugins/grpc-web/handler.lua b/kong/plugins/grpc-web/handler.lua
index ce6ec660a414..437f92f119a0 100644
--- a/kong/plugins/grpc-web/handler.lua
+++ b/kong/plugins/grpc-web/handler.lua
@@ -12,7 +12,6 @@ local ngx_arg = ngx.arg
 local ngx_var = ngx.var
 
 local kong_request_get_path = kong.request.get_path
--- local kong_request_get_header = kong.request.get_header
 local kong_request_get_method = kong.request.get_method
 local kong_request_get_raw_body = kong.request.get_raw_body
 local kong_response_exit = kong.response.exit
@@ -51,7 +50,6 @@ function grpc_web:access(conf)
   end
 
   local dec, err = deco.new(
-    -- kong_request_get_header("Content-Type"),
     ngx.var.http_content_type,
     uri, conf.proto)
 
diff --git a/kong/plugins/hmac-auth/access.lua b/kong/plugins/hmac-auth/access.lua
index e8acb4381d52..cd4acaedbbc7 100644
--- a/kong/plugins/hmac-auth/access.lua
+++ b/kong/plugins/hmac-auth/access.lua
@@ -127,11 +127,12 @@ end
 
 -- plugin assumes the request parameters being used for creating
 -- signature by client are not changed by core or any other plugin
-local function create_hash(request_uri, hmac_params, ctx)
+local function create_hash(request_uri, hmac_params)
   local signing_string = ""
   local hmac_headers = hmac_params.hmac_headers
 
   local count = #hmac_headers
+  local ctx = {}
   for i = 1, count do
     local header = hmac_headers[i]
     local header_value = kong.request.get_header(header, ctx)
@@ -166,8 +167,8 @@ local function create_hash(request_uri, hmac_params, ctx)
 end
 
 
-local function validate_signature(hmac_params, ctx)
-  local signature_1 = create_hash(kong_request.get_path_with_query(), hmac_params, ctx)
+local function validate_signature(hmac_params)
+  local signature_1 = create_hash(kong_request.get_path_with_query(), hmac_params)
   local signature_2 = decode_base64(hmac_params.signature)
   return signature_1 == signature_2
 end
@@ -330,9 +331,7 @@ local function do_authentication(conf)
 
   hmac_params.secret = credential.secret
 
-  -- since there are `clear_header` call before, we reset ctx, to get fresh headers
-  ctx = {}
-  if not validate_signature(hmac_params, ctx) then
+  if not validate_signature(hmac_params) then
     return false, unauthorized(SIGNATURE_NOT_SAME, www_auth_content)
   end
 
diff --git a/kong/plugins/oauth2/access.lua b/kong/plugins/oauth2/access.lua
index 8d2565a7a401..8b1dcb5ea95e 100644
--- a/kong/plugins/oauth2/access.lua
+++ b/kong/plugins/oauth2/access.lua
@@ -877,7 +877,6 @@ local function parse_access_token(conf)
       parameters[ACCESS_TOKEN] = nil
       kong.service.request.set_query(parameters)
 
-      -- local content_type = kong.request.get_header("content-type")
       local content_type = ngx.var.http_content_type
       local is_form_post = content_type and
         string_find(content_type, "application/x-www-form-urlencoded", 1, true)
diff --git a/kong/plugins/request-transformer/access.lua b/kong/plugins/request-transformer/access.lua
index 80006542e2da..dc47278ae1ea 100644
--- a/kong/plugins/request-transformer/access.lua
+++ b/kong/plugins/request-transformer/access.lua
@@ -8,7 +8,6 @@ local table_insert = table.insert
 local get_uri_args = kong.request.get_query
 local set_uri_args = kong.service.request.set_query
 local clear_header = kong.service.request.clear_header
--- local get_header = kong.request.get_header
 local var = ngx.var
 local set_header = kong.service.request.set_header
 local get_headers = kong.request.get_headers
@@ -423,7 +422,6 @@ local function transform_multipart_body(conf, body, content_length, content_type
 end
 
 local function transform_body(conf, template_env)
-  -- local content_type_value = get_header(CONTENT_TYPE)
   -- content-type is a builtin single value header, use var to fetch is faster.
   local content_type_value = var.http_content_type
   local content_type = get_content_type(content_type_value)
@@ -459,7 +457,6 @@ local function transform_method(conf)
   if conf.http_method then
     set_method(conf.http_method:upper())
     if conf.http_method == "GET" or conf.http_method == "HEAD" or conf.http_method == "TRACE" then
-      -- local content_type_value = get_header(CONTENT_TYPE)
       -- content-type is a builtin single value header, use var to fetch is faster.
       local content_type_value = var.http_content_type
       local content_type = get_content_type(content_type_value)
diff --git a/t/01-pdk/08-response/02-get_header.t b/t/01-pdk/08-response/02-get_header.t
index 378e1f9cdbef..c6bec909981a 100644
--- a/t/01-pdk/08-response/02-get_header.t
+++ b/t/01-pdk/08-response/02-get_header.t
@@ -116,7 +116,7 @@ X-Missing: nil
 
 
 
-=== TEST 4: response.get_header() returns existing header will not by limited by get_headers() default max_headers configuration
+=== TEST 4: response.get_header() returns existing header will not limited by get_headers() default max_headers configuration
 --- http_config eval: $t::Util::HttpConfig
 --- config
     location = /t {