DATAREDIS-1062 - Disable select dbIndex in case dbIndex is 0.

When shareNativeConnection was set to false and enabled connection pooling before executing each Redis command, select dbIndex command was executed. Selecting the database can be superfluous when the connection already uses the right database index. Original pull request: spring-projects#496.

Author: tamilselvan-chinnaswamy

src/main/java/org/springframework/data/redis/connection/lettuce/LettuceConnection.java

@@ -975,10 +975,13 @@ RedisClusterCommands<byte[], byte[]> getDedicatedConnection() {
 if (asyncDedicatedConn == null) {
 
 asyncDedicatedConn = doGetAsyncDedicatedConnection();
-
-if (asyncDedicatedConn instanceof StatefulRedisConnection) {
+
+if (asyncDedicatedConn instanceof StatefulRedisConnection && dbIndex > 0) {
 ((StatefulRedisConnection<byte[], byte[]>) asyncDedicatedConn).sync().select(dbIndex);
 }
+else if (asyncDedicatedConn instanceof StatefulRedisConnection) {
+((StatefulRedisConnection<byte[], byte[]>) asyncDedicatedConn).sync();
+}
 }
 
 if (asyncDedicatedConn instanceof StatefulRedisConnection) {