diff --git a/kong/global.lua b/kong/global.lua
index b3d98cccc1e8..0cb42c006406 100644
--- a/kong/global.lua
+++ b/kong/global.lua
@@ -51,11 +51,36 @@ function _GLOBAL.set_named_ctx(self, name, key)
     error("name cannot be an empty string", 2)
   end
 
+  if key == nil then
+    error("key cannot be nil", 2)
+  end
+
+  if not self.ctx then
+    error("ctx PDK module not initialized", 2)
+  end
+
+  self.ctx.__set_namespace(name, key)
+end
+
+
+function _GLOBAL.del_named_ctx(self, name)
+  if not self then
+    error("arg #1 cannot be nil", 2)
+  end
+
+  if type(name) ~= "string" then
+    error("name must be a string", 2)
+  end
+
+  if #name == 0 then
+    error("name cannot be an empty string", 2)
+  end
+
   if not self.ctx then
     error("ctx PDK module not initialized", 2)
   end
 
-  self.ctx.keys[name] = key
+  self.ctx.__del_namespace(name)
 end
 
 
diff --git a/kong/pdk/ctx.lua b/kong/pdk/ctx.lua
index 353164ace197..cbc9918cbb35 100644
--- a/kong/pdk/ctx.lua
+++ b/kong/pdk/ctx.lua
@@ -4,6 +4,7 @@
 
 
 local ngx = ngx
+local ngx_get_phase = ngx.get_phase
 
 
 -- shared between all global instances
@@ -11,6 +12,10 @@ local _CTX_SHARED_KEY = {}
 local _CTX_CORE_KEY = {}
 
 
+-- dynamic namespaces, also shared between global instances
+local _CTX_NAMESPACES_KEY = {}
+
+
 ---
 -- A table that has the lifetime of the current request and is shared between
 -- all plugins. It can be used to share data between several plugins in a given
@@ -86,19 +91,58 @@ local _CTX_CORE_KEY = {}
 --
 --   kong.log(value) -- "hello world"
 -- end
-local function new(self)
-  local _CTX = {
-    -- those would be visible on the *.ctx namespace for now
-    -- TODO: hide them in a private table shared between this
-    -- module and the global.lua one
-    keys = setmetatable({}, { __mode = "v" }),
-  }
 
 
+local function new(self)
+  local _CTX = {}
   local _ctx_mt = {}
+  local _ns_mt = { __mode = "v" }
+
+
+  local function get_namespaces(nctx)
+    local namespaces = nctx[_CTX_NAMESPACES_KEY]
+    if not namespaces then
+      -- 4 namespaces for request, i.e. ~4 plugins
+      namespaces = self.table.new(0, 4)
+      nctx[_CTX_NAMESPACES_KEY] = setmetatable(namespaces, _ns_mt)
+    end
+
+    return namespaces
+  end
+
+
+  local function set_namespace(namespace, namespace_key)
+    local nctx = ngx.ctx
+    local namespaces = get_namespaces(nctx)
+
+    local ns = namespaces[namespace]
+    if ns and ns == namespace_key then
+      return
+    end
+
+    namespaces[namespace] = namespace_key
+  end
+
+
+  local function del_namespace(namespace)
+    local nctx = ngx.ctx
+    local namespaces = get_namespaces(nctx)
+    namespaces[namespace] = nil
+  end
 
 
   function _ctx_mt.__index(t, k)
+    if k == "__set_namespace" then
+      return set_namespace
+
+    elseif k == "__del_namespace" then
+      return del_namespace
+    end
+
+    if ngx_get_phase() == "init" then
+      return
+    end
+
     local nctx = ngx.ctx
     local key
 
@@ -109,7 +153,8 @@ local function new(self)
       key = _CTX_SHARED_KEY
 
     else
-      key = t.keys[k]
+      local namespaces = get_namespaces(nctx)
+      key = namespaces[k]
     end
 
     if key then
diff --git a/t/01-pdk/05-client/09-load-consumer.t b/t/01-pdk/05-client/09-load-consumer.t
index d092475a68c0..acc240ad403f 100644
--- a/t/01-pdk/05-client/09-load-consumer.t
+++ b/t/01-pdk/05-client/09-load-consumer.t
@@ -126,4 +126,3 @@ GET /t
 cannot load a consumer with an id that is not a uuid
 --- no_error_log
 [error]
-
diff --git a/t/02-global/02-set-named-ctx.t b/t/02-global/02-set-named-ctx.t
index 7e2478190287..6cbed4df406f 100644
--- a/t/02-global/02-set-named-ctx.t
+++ b/t/02-global/02-set-named-ctx.t
@@ -80,7 +80,7 @@ marry
 
 
 
-=== TEST 3: set_named_ctx() arbitrary namespaces can be discarded
+=== TEST 3: set_named_ctx() arbitrary namespaces can be discarded via del_named_ctx()
 --- http_config eval: $t::Util::HttpConfig
 --- config
     location = /t {
@@ -93,7 +93,7 @@ marry
             kong.ctx.custom.cats = "marry"
             ngx.say(kong.ctx.custom.cats)
 
-            kong_global.set_named_ctx(kong, "custom", nil)
+            kong_global.del_named_ctx(kong, "custom")
             ngx.say(kong.ctx.custom)
         }
     }
@@ -181,3 +181,64 @@ GET /t
 ctx PDK module not initialized
 --- no_error_log
 [error]
+
+
+
+=== TEST 7: set_named_ctx() arbitrary namespaces are light-thread safe
+--- http_config
+    init_by_lua_block {
+        kong_global = require "kong.global"
+        kong = kong_global.new()
+        kong_global.init_pdk(kong)
+    }
+--- config
+    location = /lua {
+        content_by_lua_block {
+            local args = assert(ngx.req.get_uri_args())
+            local thread_name = args.name
+            local value = args.val
+
+            kong_global.set_named_ctx(kong, "thread", thread_name)
+            kong.ctx.thread.val = value
+
+            ngx.sleep(0.1)
+
+            ngx.say("thread ", thread_name, ": ", kong.ctx.thread.val)
+        }
+    }
+
+    location = /t {
+        echo_subrequest_async GET '/lua' -q 'name=A&val=hello';
+        echo_subrequest_async GET '/lua' -q 'name=B&val=world';
+    }
+--- request
+GET /t
+--- response_body
+thread A: hello
+thread B: world
+--- no_error_log
+[error]
+
+
+
+=== TEST 8: set_named_ctx() arbitrary namespaces invalid argument 'key'
+--- http_config eval: $t::Util::HttpConfig
+--- config
+    location = /t {
+        content_by_lua_block {
+            local kong_global = require "kong.global"
+            local kong = kong_global.new()
+            kong_global.init_pdk(kong)
+
+            local pok, perr = pcall(kong_global.set_named_ctx, kong, "custom", nil)
+            if not pok then
+              ngx.say(perr)
+            end
+        }
+    }
+--- request
+GET /t
+--- response_body
+key cannot be nil
+--- no_error_log
+[error]