Use Cluster write connections for read commands when using ReadFrom.M…

…ASTER #923 Lettuce now reuses master connections when ReadFrom is configured to MASTER (which is the default configuration). By reusing the master connection, we can reduce the number of used connections by up to 50% as we don't need an additional read connection while talking to the same node.
redis · Nov 24, 2018 · ef0b15e · ef0b15e
1 parent 14db4fa
commit ef0b15e
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Showing 2 changed files with 17 additions and 1 deletion.
diff --git a/src/main/java/io/lettuce/core/cluster/PooledClusterConnectionProvider.java b/src/main/java/io/lettuce/core/cluster/PooledClusterConnectionProvider.java
@@ -104,9 +104,10 @@ public CompletableFuture<StatefulRedisConnection<K, V>> getConnectionAsync(Inten
             logger.debug("getConnection(" + intent + ", " + slot + ")");
         }
 
-        if (intent == Intent.READ && readFrom != null) {
+        if (intent == Intent.READ && readFrom != null && readFrom != ReadFrom.MASTER) {
             return getReadConnection(slot);
         }
+
         return getWriteConnection(slot).toCompletableFuture();
     }
 

diff --git a/src/test/java/io/lettuce/core/cluster/PooledClusterConnectionProviderUnitTests.java b/src/test/java/io/lettuce/core/cluster/PooledClusterConnectionProviderUnitTests.java
@@ -125,6 +125,21 @@ void shouldObtainConnection() {
         verifyNoMoreInteractions(connection);
     }
 
+    @Test
+    void shouldReuseMasterConnectionForReadFromMaster() {
+
+        when(clientMock.connectToNodeAsync(eq(CODEC), eq("localhost:1"), any(), any())).thenReturn(
+                ConnectionFuture.from(socketAddressMock, CompletableFuture.completedFuture(nodeConnectionMock)));
+
+        sut.setReadFrom(ReadFrom.MASTER);
+
+        StatefulRedisConnection<String, String> connection = sut.getConnection(Intent.READ, 1);
+
+        assertThat(connection).isSameAs(nodeConnectionMock);
+        verify(connection).setAutoFlushCommands(true);
+        verifyNoMoreInteractions(connection);
+    }
+
     @Test
     void shouldObtainConnectionReadFromSlave() {