From e9a8ff0a259453eac93e24e87ebcc9142702c71c Mon Sep 17 00:00:00 2001
From: Sriram Rangarajan <srrangarajan@netflix.com>
Date: Wed, 14 Dec 2022 11:58:19 -0800
Subject: [PATCH] Sort Clients for add

---
 .../java/com/netflix/evcache/EVCacheImpl.java   | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/evcache-core/src/main/java/com/netflix/evcache/EVCacheImpl.java b/evcache-core/src/main/java/com/netflix/evcache/EVCacheImpl.java
index 6651f142..b17450b3 100644
--- a/evcache-core/src/main/java/com/netflix/evcache/EVCacheImpl.java
+++ b/evcache-core/src/main/java/com/netflix/evcache/EVCacheImpl.java
@@ -20,6 +20,7 @@
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
 import java.util.function.Function;
+import java.util.stream.Collectors;
 
 import javax.management.MBeanServer;
 import javax.management.ObjectName;
@@ -3259,7 +3260,21 @@ public <T> boolean add(String key, T value, Transcoder<T> tc, int timeToLive) th
     @Override
     public <T> EVCacheLatch add(String key, T value, Transcoder<T> tc, int timeToLive, Policy policy) throws EVCacheException {
         EVCacheClient[] clients = _pool.getEVCacheClientForWrite();
-        return this.add(key, value, tc, timeToLive, policy, clients, clients.length - _pool.getWriteOnlyEVCacheClients().length);
+        EVCacheClient[] writeOnlyClients = _pool.getWriteOnlyEVCacheClients();
+        // In case of adds , we skip adds to the pool if value is already present in the 1st client
+        // Sorting to make sure the 1st element of the list is a read/write client and not just write-only client
+        EVCacheClient[] sortedClients = sortClients(clients, writeOnlyClients);
+        return this.add(key, value, tc, timeToLive, policy, sortedClients, clients.length - _pool.getWriteOnlyEVCacheClients().length);
+    }
+
+    public EVCacheClient[] sortClients(EVCacheClient[] clients, EVCacheClient[] writeOnlyClients) {
+        List<EVCacheClient> writeOnlyClientsList = Arrays.asList(writeOnlyClients);
+        List<EVCacheClient> clientList = Arrays.stream(clients).sorted((s1, s2) -> {
+            if (writeOnlyClientsList.contains(s1))
+                return 1;
+            return -1;
+        }).collect(Collectors.toList());
+        return clientList.stream().toArray(EVCacheClient[]::new);
     }
 
     protected <T> EVCacheLatch add(String key, T value, Transcoder<T> tc, int timeToLive, Policy policy, EVCacheClient[] clients, int latchCount) throws EVCacheException {