perf: compare service discovery nodes by addresss (#12258)

Author: nic-6443

apisix/upstream.lua

@@ -108,7 +108,8 @@ local function create_checker(upstream)
     end
 
     local healthcheck_parent = upstream.parent
-    if healthcheck_parent.checker and healthcheck_parent.checker_upstream == upstream then
+    if healthcheck_parent.checker and healthcheck_parent.checker_upstream == upstream
+        and healthcheck_parent.checker_nodes_ver == upstream._nodes_ver then
         return healthcheck_parent.checker
     end
 
@@ -175,6 +176,7 @@ local function create_checker(upstream)
 
     healthcheck_parent.checker = checker
     healthcheck_parent.checker_upstream = upstream
+    healthcheck_parent.checker_nodes_ver = upstream._nodes_ver
     healthcheck_parent.checker_idx = check_idx
 
     upstream.is_creating_checker = nil
@@ -302,35 +304,30 @@ function _M.set_by_route(route, api_ctx)
 
         local same = upstream_util.compare_upstream_node(up_conf, new_nodes)
         if not same then
+            if not up_conf._nodes_ver then
+                up_conf._nodes_ver = 0
+            end
+            up_conf._nodes_ver = up_conf._nodes_ver + 1
+
             local pass, err = core.schema.check(core.schema.discovery_nodes, new_nodes)
             if not pass then
                 return HTTP_CODE_UPSTREAM_UNAVAILABLE, "invalid nodes format: " .. err
             end
 
-            local new_up_conf = core.table.clone(up_conf)
-            new_up_conf.nodes = new_nodes
-            new_up_conf.original_nodes = up_conf.nodes
+            up_conf.nodes = new_nodes
 
             core.log.info("discover new upstream from ", up_conf.service_name, ", type ",
                           up_conf.discovery_type, ": ",
-                          core.json.delay_encode(new_up_conf, true))
-
-            local parent = up_conf.parent
-            if parent.value.upstream then
-                -- the up_conf comes from route or service
-                parent.value.upstream = new_up_conf
-            else
-                parent.value = new_up_conf
-            end
-            up_conf = new_up_conf
+                          core.json.delay_encode(up_conf, true))
         end
     end
 
     local id = up_conf.parent.value.id
     local conf_version = up_conf.parent.modifiedIndex
     -- include the upstream object as part of the version, because the upstream will be changed
     -- by service discovery or dns resolver.
-    set_directly(api_ctx, id, conf_version .. "#" .. tostring(up_conf), up_conf)
+    set_directly(api_ctx, id, conf_version .. "#" .. tostring(up_conf) .. "#"
+                                    .. tostring(up_conf._nodes_ver or ''), up_conf)
 
     local nodes_count = up_conf.nodes and #up_conf.nodes or 0
     if nodes_count == 0 then

apisix/utils/upstream.lua

@@ -35,6 +35,10 @@ local function compare_upstream_node(up_conf, new_t)
     end
 
     local old_t = up_conf.original_nodes or up_conf.nodes
+    if old_t == new_t then
+        return true
+    end
+
     if type(old_t) ~= "table" then
         return false
     end