diff --git a/CHANGES.txt b/CHANGES.txt
index 60a69940a2..4a581404cb 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)
  * Reduce number of scheduledTasks on metric id release in ThreadLocalMetrics (CASSANDRA-21475)
  * Cache various Enum.values() used in deserialization to avoid per-read array allocation (CASSANDRA-21528)
  * Fix Accord transaction error message when altering a table (CASSANDRA-20580)
diff --git a/src/java/org/apache/cassandra/config/DatabaseDescriptor.java b/src/java/org/apache/cassandra/config/DatabaseDescriptor.java
index 106ab02e24..5bc6de7ac1 100644
--- a/src/java/org/apache/cassandra/config/DatabaseDescriptor.java
+++ b/src/java/org/apache/cassandra/config/DatabaseDescriptor.java
@@ -85,6 +85,7 @@ import org.apache.cassandra.config.Config.DiskAccessMode;
 import org.apache.cassandra.config.Config.PaxosOnLinearizabilityViolation;
 import org.apache.cassandra.config.Config.PaxosStatePurging;
 import org.apache.cassandra.config.DurationSpec.IntMillisecondsBound;
+import org.apache.cassandra.cql3.QueryOptions;
 import org.apache.cassandra.db.ConsistencyLevel;
 import org.apache.cassandra.db.commitlog.AbstractCommitLogSegmentManager;
 import org.apache.cassandra.db.commitlog.CommitLog;
@@ -273,6 +274,8 @@ public class DatabaseDescriptor
 
     public static volatile boolean allowUnlimitedConcurrentValidations = ALLOW_UNLIMITED_CONCURRENT_VALIDATIONS.getBoolean();
 
+    private static volatile QueryOptions.DefaultReadThresholds defaultReadThresholds;
+
     /**
      * RetryStrategy which provides exponential backoff with full jitter, for use by both CMS and non-CMS members
      * when submitting a Commit request. The range and increments of the backoff times are defined by
@@ -332,6 +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");
@@ -5571,6 +5575,14 @@ public class DatabaseDescriptor
         return conf.invalid_legacy_protocol_magic_no_spam_enabled;
     }
 
+    public static QueryOptions.DefaultReadThresholds getDefaultReadThresholds()
+    {
+        if (defaultReadThresholds == null)
+            defaultReadThresholds = new QueryOptions.DefaultReadThresholds(getCoordinatorReadSizeWarnThreshold(),
+                                                                           getCoordinatorReadSizeFailThreshold());
+        return defaultReadThresholds;
+    }
+
     public static boolean getReadThresholdsEnabled()
     {
         return conf.read_thresholds_enabled;
@@ -5595,6 +5607,7 @@ public class DatabaseDescriptor
     {
         logger.info("updating  coordinator_read_size_warn_threshold to {}", value);
         conf.coordinator_read_size_warn_threshold = value;
+        defaultReadThresholds = null;
     }
 
     @Nullable
@@ -5607,6 +5620,7 @@ public class DatabaseDescriptor
     {
         logger.info("updating  coordinator_read_size_fail_threshold to {}", value);
         conf.coordinator_read_size_fail_threshold = value;
+        defaultReadThresholds = null;
     }
 
     @Nullable
diff --git a/src/java/org/apache/cassandra/cql3/QueryOptions.java b/src/java/org/apache/cassandra/cql3/QueryOptions.java
index afc5bacc38..78910e5788 100644
--- a/src/java/org/apache/cassandra/cql3/QueryOptions.java
+++ b/src/java/org/apache/cassandra/cql3/QueryOptions.java
@@ -322,7 +322,7 @@ public abstract class QueryOptions implements RealTimeFunctionContext
             // if daemon initialization hasn't happened yet (very common in tests) then ignore
             if (!DatabaseDescriptor.isDaemonInitialized() || !DatabaseDescriptor.getReadThresholdsEnabled())
                 return DisabledReadThresholds.INSTANCE;
-            return new DefaultReadThresholds(DatabaseDescriptor.getCoordinatorReadSizeWarnThreshold(), DatabaseDescriptor.getCoordinatorReadSizeFailThreshold());
+            return DatabaseDescriptor.getDefaultReadThresholds();
         }
     }
 
@@ -349,7 +349,7 @@ public abstract class QueryOptions implements RealTimeFunctionContext
         }
     }
 
-    private static class DefaultReadThresholds implements ReadThresholds
+    public static class DefaultReadThresholds implements ReadThresholds
     {
         private final long warnThresholdBytes;
         private final long abortThresholdBytes;
diff --git a/test/unit/org/apache/cassandra/config/DatabaseDescriptorRefTest.java b/test/unit/org/apache/cassandra/config/DatabaseDescriptorRefTest.java
index 1704936544..1f9e833e1b 100644
--- a/test/unit/org/apache/cassandra/config/DatabaseDescriptorRefTest.java
+++ b/test/unit/org/apache/cassandra/config/DatabaseDescriptorRefTest.java
@@ -198,6 +198,8 @@ public class DatabaseDescriptorRefTest
     "org.apache.cassandra.config.YamlConfigurationLoader$CustomConstructor",
     "org.apache.cassandra.config.YamlConfigurationLoader$PropertiesChecker",
     "org.apache.cassandra.config.YamlConfigurationLoader$PropertiesChecker$1",
+    "org.apache.cassandra.cql3.QueryOptions$DefaultReadThresholds",
+    "org.apache.cassandra.cql3.QueryOptions$ReadThresholds",
     "org.apache.cassandra.db.ConsistencyLevel",
     "org.apache.cassandra.db.commitlog.AbstractCommitLogSegmentManager",
     "org.apache.cassandra.db.commitlog.CommitLog",