diff --git a/bookkeeper-server/src/main/java/org/apache/bookkeeper/proto/PerChannelBookieClient.java b/bookkeeper-server/src/main/java/org/apache/bookkeeper/proto/PerChannelBookieClient.java
index 2cda0d243bb..06b15178741 100644
--- a/bookkeeper-server/src/main/java/org/apache/bookkeeper/proto/PerChannelBookieClient.java
+++ b/bookkeeper-server/src/main/java/org/apache/bookkeeper/proto/PerChannelBookieClient.java
@@ -182,7 +182,7 @@ public class PerChannelBookieClient extends ChannelInboundHandlerAdapter {
     final int startTLSTimeout;
 
     private final ConcurrentOpenHashMap<CompletionKey, CompletionValue> completionObjects =
-            ConcurrentOpenHashMap.<CompletionKey, CompletionValue>newBuilder().build();
+            ConcurrentOpenHashMap.<CompletionKey, CompletionValue>newBuilder().autoShrink(true).build();
 
     // Map that hold duplicated read requests. The idea is to only use this map (synchronized) when there is a duplicate
     // read request for the same ledgerId/entryId