diff --git a/apisix/plugins/datadog.lua b/apisix/plugins/datadog.lua
index 6a55886f..b613bac9 100644
--- a/apisix/plugins/datadog.lua
+++ b/apisix/plugins/datadog.lua
@@ -26,6 +26,7 @@ local format = string.format
 local concat = table.concat
 local buffers = {}
 local ipairs = ipairs
+local pairs = pairs
 local tostring = tostring
 local stale_timer_running = false
 local timer_at = ngx.timer.at
@@ -120,7 +121,7 @@ local function remove_stale_objects(premature)
         return
     end
 
-    for key, batch in ipairs(buffers) do
+    for key, batch in pairs(buffers) do
         if #batch.entry_buffer.entries == 0 and #batch.batch_to_process == 0 then
             core.log.warn("removing batch processor stale object, conf: ",
                           core.json.delay_encode(key))
diff --git a/apisix/plugins/google-cloud-logging.lua b/apisix/plugins/google-cloud-logging.lua
index 961762d2..a233d3f5 100644
--- a/apisix/plugins/google-cloud-logging.lua
+++ b/apisix/plugins/google-cloud-logging.lua
@@ -18,7 +18,7 @@
 local core            = require("apisix.core")
 local ngx             = ngx
 local tostring        = tostring
-local ipairs          = ipairs
+local pairs           = pairs
 local ngx_timer_at    = ngx.timer.at
 local http            = require("resty.http")
 local log_util        = require("apisix.utils.log-util")
@@ -128,7 +128,7 @@ local function remove_stale_objects(premature)
         return
     end
 
-    for key, batch in ipairs(buffers) do
+    for key, batch in pairs(buffers) do
         if #batch.entry_buffer.entries == 0 and #batch.batch_to_process == 0 then
             core.log.warn("removing batch processor stale object, route id:", tostring(key))
             buffers[key] = nil
diff --git a/apisix/plugins/http-logger.lua b/apisix/plugins/http-logger.lua
index b52c1adc..a4eadb3f 100644
--- a/apisix/plugins/http-logger.lua
+++ b/apisix/plugins/http-logger.lua
@@ -25,6 +25,7 @@ local plugin          = require("apisix.plugin")
 local ngx      = ngx
 local tostring = tostring
 local ipairs   = ipairs
+local pairs    = pairs
 local timer_at = ngx.timer.at
 
 local plugin_name = "http-logger"
@@ -166,7 +167,7 @@ local function remove_stale_objects(premature)
         return
     end
 
-    for key, batch in ipairs(buffers) do
+    for key, batch in pairs(buffers) do
         if #batch.entry_buffer.entries == 0 and #batch.batch_to_process == 0 then
             core.log.warn("removing batch processor stale object, conf: ",
                           core.json.delay_encode(key))
diff --git a/apisix/plugins/kafka-logger.lua b/apisix/plugins/kafka-logger.lua
index def042fe..01439225 100644
--- a/apisix/plugins/kafka-logger.lua
+++ b/apisix/plugins/kafka-logger.lua
@@ -23,7 +23,6 @@ local plugin = require("apisix.plugin")
 local math     = math
 local pairs    = pairs
 local type     = type
-local ipairs   = ipairs
 local plugin_name = "kafka-logger"
 local stale_timer_running = false
 local timer_at = ngx.timer.at
@@ -164,7 +163,7 @@ local function remove_stale_objects(premature)
         return
     end
 
-    for key, batch in ipairs(buffers) do
+    for key, batch in pairs(buffers) do
         if #batch.entry_buffer.entries == 0 and #batch.batch_to_process == 0 then
             core.log.warn("removing batch processor stale object, conf: ",
                           core.json.delay_encode(key))
diff --git a/apisix/plugins/skywalking-logger.lua b/apisix/plugins/skywalking-logger.lua
index 58f25b84..bd5f9c11 100644
--- a/apisix/plugins/skywalking-logger.lua
+++ b/apisix/plugins/skywalking-logger.lua
@@ -28,7 +28,7 @@ local ngx_re          = require("ngx.re")
 local ngx      = ngx
 local tostring = tostring
 local tonumber = tonumber
-local ipairs   = ipairs
+local pairs    = pairs
 local timer_at = ngx.timer.at
 
 local plugin_name = "skywalking-logger"
@@ -130,7 +130,7 @@ local function remove_stale_objects(premature)
         return
     end
 
-    for key, batch in ipairs(buffers) do
+    for key, batch in pairs(buffers) do
         if #batch.entry_buffer.entries == 0 and #batch.batch_to_process == 0 then
             core.log.warn("removing batch processor stale object, conf: ",
                           core.json.delay_encode(key))
diff --git a/apisix/plugins/sls-logger.lua b/apisix/plugins/sls-logger.lua
index daeaebb7..797b85fd 100644
--- a/apisix/plugins/sls-logger.lua
+++ b/apisix/plugins/sls-logger.lua
@@ -26,6 +26,7 @@ local tcp = ngx.socket.tcp
 local buffers = {}
 local tostring = tostring
 local ipairs = ipairs
+local pairs = pairs
 local table = table
 local schema = {
     type = "object",
@@ -116,7 +117,7 @@ local function remove_stale_objects(premature)
         return
     end
 
-    for key, batch in ipairs(buffers) do
+    for key, batch in pairs(buffers) do
         if #batch.entry_buffer.entries == 0 and #batch.batch_to_process == 0 then
             core.log.warn("removing batch processor stale object, route id:", tostring(key))
             buffers[key] = nil
diff --git a/apisix/plugins/syslog.lua b/apisix/plugins/syslog.lua
index a3ec8229..3eed59ff 100644
--- a/apisix/plugins/syslog.lua
+++ b/apisix/plugins/syslog.lua
@@ -22,7 +22,7 @@ local logger_socket = require("resty.logger.socket")
 local plugin_name = "syslog"
 local ngx = ngx
 local buffers = {}
-local ipairs   = ipairs
+local pairs = pairs
 local stale_timer_running = false;
 local timer_at = ngx.timer.at
 
@@ -121,7 +121,7 @@ local function remove_stale_objects(premature)
         return
     end
 
-    for key, batch in ipairs(buffers) do
+    for key, batch in pairs(buffers) do
         if #batch.entry_buffer.entries == 0 and #batch.batch_to_process == 0 then
             core.log.warn("removing batch processor stale object, conf: ",
                           core.json.delay_encode(key))
diff --git a/apisix/plugins/tcp-logger.lua b/apisix/plugins/tcp-logger.lua
index dc4cb212..8d678b33 100644
--- a/apisix/plugins/tcp-logger.lua
+++ b/apisix/plugins/tcp-logger.lua
@@ -22,7 +22,7 @@ local tostring = tostring
 local buffers = {}
 local ngx = ngx
 local tcp = ngx.socket.tcp
-local ipairs   = ipairs
+local pairs = pairs
 local stale_timer_running = false
 local timer_at = ngx.timer.at
 
@@ -106,7 +106,7 @@ local function remove_stale_objects(premature)
         return
     end
 
-    for key, batch in ipairs(buffers) do
+    for key, batch in pairs(buffers) do
         if #batch.entry_buffer.entries == 0 and #batch.batch_to_process == 0 then
             core.log.warn("removing batch processor stale object, conf: ",
                           core.json.delay_encode(key))
diff --git a/apisix/plugins/udp-logger.lua b/apisix/plugins/udp-logger.lua
index 06f903e6..97e6552c 100644
--- a/apisix/plugins/udp-logger.lua
+++ b/apisix/plugins/udp-logger.lua
@@ -22,7 +22,7 @@ local tostring = tostring
 local buffers = {}
 local ngx = ngx
 local udp = ngx.socket.udp
-local ipairs   = ipairs
+local pairs = pairs
 local stale_timer_running = false;
 local timer_at = ngx.timer.at
 
@@ -90,7 +90,7 @@ local function remove_stale_objects(premature)
         return
     end
 
-    for key, batch in ipairs(buffers) do
+    for key, batch in pairs(buffers) do
         if #batch.entry_buffer.entries == 0 and #batch.batch_to_process == 0 then
             core.log.warn("removing batch processor stale object, conf: ",
                           core.json.delay_encode(key))