From 3bf9bd6831ae23670f0113b5d858e4dc00448ce5 Mon Sep 17 00:00:00 2001
From: Mick Semb Wever <mck@apache.org>
Date: Thu, 9 Mar 2023 14:11:19 +0100
Subject: [PATCH] Remove legacy 3.0/3.11 buffer pool metrics

 patch by Mick Semb Wever; reviewed by Brandon Williams, Maxim Muzafarov for CASSANDRA-18313
---
 CHANGES.txt                                              | 1 +
 NEWS.txt                                                 | 2 ++
 .../org/apache/cassandra/metrics/BufferPoolMetrics.java  | 9 ---------
 .../org/apache/cassandra/utils/memory/BufferPools.java   | 1 -
 .../org/apache/cassandra/tools/JMXCompatabilityTest.java | 8 ++++++--
 5 files changed, 9 insertions(+), 12 deletions(-)

diff --git a/CHANGES.txt b/CHANGES.txt
index 08cc8a5e8a..1b02aa51bd 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -1,4 +1,5 @@
 5.0
+ * Remove legacy 3.0/3.11 buffer pool metrics (CASSANDRA-18313)
  * Add AzureSnitch (CASSANDRA-18646)
  * Implementation of the Unified Compaction Strategy as described in CEP-26 (CASSANDRA-18397)
  * Upgrade commons cli to 1.5.0 (CASSANDRA-18659)
diff --git a/NEWS.txt b/NEWS.txt
index 26be1a6bde..ff90a9a465 100644
--- a/NEWS.txt
+++ b/NEWS.txt
@@ -202,6 +202,8 @@ Upgrading
      communicate with AWS IMDS of version 2. This change is transparent, there does not need 
      to be done anything upon upgrade. Furthermore, IMDS of version 2 can be configured to be required in AWS EC2 console.
      Consult cassandra-rackdc.properties for more details. (CASSANDRA-16555)
+    - JMX MBean `org.apache.cassandra.metrics:type=BufferPool` without scope has been removed.
+      Use instead `org.apache.cassandra.metrics:type=BufferPool,scope=chunk-cache`.  (CASSANDRA-17668)
 
 
 Deprecation
diff --git a/src/java/org/apache/cassandra/metrics/BufferPoolMetrics.java b/src/java/org/apache/cassandra/metrics/BufferPoolMetrics.java
index b79a8fea26..71373b35e8 100644
--- a/src/java/org/apache/cassandra/metrics/BufferPoolMetrics.java
+++ b/src/java/org/apache/cassandra/metrics/BufferPoolMetrics.java
@@ -64,13 +64,4 @@ public class BufferPoolMetrics
         size = Metrics.register(factory.createMetricName("Size"), bufferPool::sizeInBytes);
     }
 
-    /**
-     * used to register alias for 3.0/3.11 compatibility
-     */
-    public void register3xAlias()
-    {
-        MetricNameFactory legacyFactory = new DefaultNameFactory("BufferPool");
-        Metrics.registerMBean(misses, legacyFactory.createMetricName("Misses").getMBeanName());
-        Metrics.registerMBean(size, legacyFactory.createMetricName("Size").getMBeanName());
-    }
 }
diff --git a/src/java/org/apache/cassandra/utils/memory/BufferPools.java b/src/java/org/apache/cassandra/utils/memory/BufferPools.java
index 5d80881961..aba5900b70 100644
--- a/src/java/org/apache/cassandra/utils/memory/BufferPools.java
+++ b/src/java/org/apache/cassandra/utils/memory/BufferPools.java
@@ -52,7 +52,6 @@ public class BufferPools
                     prettyPrintMemory(NETWORKING_MEMORY_USAGE_THRESHOLD),
                     NETWORKING_POOL.name);
 
-        CHUNK_CACHE_POOL.metrics().register3xAlias();
     }
     /**
      * Long-lived buffers used for chunk cache and other disk access
diff --git a/test/unit/org/apache/cassandra/tools/JMXCompatabilityTest.java b/test/unit/org/apache/cassandra/tools/JMXCompatabilityTest.java
index 59485de233..e37c574713 100644
--- a/test/unit/org/apache/cassandra/tools/JMXCompatabilityTest.java
+++ b/test/unit/org/apache/cassandra/tools/JMXCompatabilityTest.java
@@ -97,6 +97,7 @@ public class JMXCompatabilityTest extends CQLTester
     {
         List<String> excludeObjects = newArrayList("org.apache.cassandra.metrics:type=ThreadPools.*",
                                                    "org.apache.cassandra.internal:.*",
+                                                   "org.apache.cassandra.metrics:type=BufferPool,name=(Misses|Size)", // removed in CASSANDRA-18313
                                                    "org.apache.cassandra.metrics:type=DroppedMessage.*",
                                                    "org.apache.cassandra.metrics:type=ClientRequest,scope=CASRead,name=ConditionNotMet",
                                                    "org.apache.cassandra.metrics:type=Client,name=connectedThriftClients", // removed in CASSANDRA-11115
@@ -133,6 +134,7 @@ public class JMXCompatabilityTest extends CQLTester
     {
         List<String> excludeObjects = newArrayList("org.apache.cassandra.metrics:type=ThreadPools.*", //lazy initialization in 4.0
                                                    "org.apache.cassandra.internal:.*",
+                                                   "org.apache.cassandra.metrics:type=BufferPool,name=(Misses|Size)", // removed in CASSANDRA-18313
                                                    "org.apache.cassandra.metrics:type=DroppedMessage,scope=PAGED_RANGE.*", //it was deprecated in the previous major version
                                                    "org.apache.cassandra.metrics:type=Client,name=connectedThriftClients", // removed in CASSANDRA-11115
                                                    "org.apache.cassandra.request:type=ReadRepairStage", // removed in CASSANDRA-13910
@@ -169,7 +171,8 @@ public class JMXCompatabilityTest extends CQLTester
     @Test
     public void diff40() throws Throwable
     {
-        List<String> excludeObjects = newArrayList();
+        List<String> excludeObjects = newArrayList("org.apache.cassandra.metrics:type=BufferPool,name=(Misses|Size)" // removed in CASSANDRA-18313
+                );
         List<String> excludeAttributes = newArrayList();
         List<String> excludeOperations = newArrayList();
 
@@ -185,7 +188,8 @@ public class JMXCompatabilityTest extends CQLTester
     @Test
     public void diff41() throws Throwable
     {
-        List<String> excludeObjects = newArrayList();
+        List<String> excludeObjects = newArrayList("org.apache.cassandra.metrics:type=BufferPool,name=(Misses|Size)" // removed in CASSANDRA-18313
+        );
         List<String> excludeAttributes = newArrayList();
         List<String> excludeOperations = newArrayList();