diff --git a/CHANGES.txt b/CHANGES.txt
index fa846a9e43..105bdc1c26 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -6,6 +6,7 @@
  * Allow nodetool garbagecollect to take a user defined list of SSTables (CASSANDRA-16767)
  * Add a guardrail for misprepared statements (CASSANDRA-21139)
 Merged from 6.0:
+ * Reduce allocations in DefaultQueryOptions (CASSANDRA-21467)
  * Allow unreserved keywords as user and identity names in USER and IDENTITY statements (CASSANDRA-21510)
  * Reduce allocations in DefaultQueryOptions (CASSANDRA-21467)
  * Reduce number of scheduledTasks on metric id release in ThreadLocalMetrics (CASSANDRA-21475)
diff --git a/src/java/org/apache/cassandra/config/DatabaseDescriptor.java b/src/java/org/apache/cassandra/config/DatabaseDescriptor.java
index 803662d6d0..5bc6de7ac1 100644
--- a/src/java/org/apache/cassandra/config/DatabaseDescriptor.java
+++ b/src/java/org/apache/cassandra/config/DatabaseDescriptor.java
@@ -335,6 +335,7 @@ public class DatabaseDescriptor
     private static void clear()
     {
         sstableFormats = null;
+        defaultReadThresholds = null;
         clearMBean("org.apache.cassandra.db:type=DynamicEndpointSnitch");
         clearMBean("org.apache.cassandra.db:type=EndpointSnitchInfo");
         clearMBean("org.apache.cassandra.db:type=LocationInfo");
@@ -5606,7 +5607,7 @@ public class DatabaseDescriptor
     {
         logger.info("updating  coordinator_read_size_warn_threshold to {}", value);
         conf.coordinator_read_size_warn_threshold = value;
-        defaultReadThresholds = new QueryOptions.DefaultReadThresholds(value, getCoordinatorReadSizeFailThreshold());
+        defaultReadThresholds = null;
     }
 
     @Nullable
@@ -5619,7 +5620,7 @@ public class DatabaseDescriptor
     {
         logger.info("updating  coordinator_read_size_fail_threshold to {}", value);
         conf.coordinator_read_size_fail_threshold = value;
-        defaultReadThresholds = new QueryOptions.DefaultReadThresholds(getCoordinatorReadSizeWarnThreshold(), value);
+        defaultReadThresholds = null;
     }
 
     @Nullable