After deploying our application on Google Container engine and connecting to Google Cloud Sql through Cloud Sql proxy as per official documentation ,api's response time has been increased by at-least 100 ms as compare to connecting to Cloud Sql via ip whitelisting from Google Compute Engine instance .

I have wrote a simple api which was starting a transaction on mysql and committing it using hibernate . Below are the results

+-----------------+--------------------+-----------------+-----------------+
| App Deployed on | Number of Requests | 99th percentile | Connecting Via  |
+-----------------+--------------------+-----------------+-----------------+
| GKE             |              20140 |           113ms | Cloud Sql Proxy |
| GCE             |              20895 |            13ms | IP whitelisting |
+-----------------+--------------------+-----------------+-----------------+

My app is based on Dropwizard framework and I am using dropwizard-hibernate,below is connection configuration , which is same for both GCE and GKE :

database:
  driverClass: com.mysql.jdbc.Driver
  user: db_user
  password: db_user_pass

  url: jdbc:mysql://HOST_IP/db_name?autoReconnect=true&useUnicode=true&characterEncoding=UTF-8
  maxWaitForConnection: 1s      
  validationQuery: "SELECT 1"    
  minSize: 8    
  maxSize: 42
  properties:
      charSet: UTF-8         
      hibernate.hbm2ddl.auto: validate         
  checkConnectionWhileIdle: false
  maxConnectionAge : 10s
  checkConnectionOnBorrow: true

Api code on which above experiment has been run .

    @GET
    @Path("/response/test")
    @UnitOfWork
    public LeaderBoardResp getLeaderBoardTest(){
        long timeSpent = System.currentTimeMillis() - RequestThreadContext.get().getStartTimeMillis();
        log.info(" Got a request on test api");
        Stopwatch stopWatch = Stopwatch.createStarted();
        try {
            LeaderBoardResp leaderBoardResp = new LeaderBoardResp();
//                    fetchLeaderBoard.fetchLeaderBoard(leaderBoardReq);
            return leaderBoardResp;
        }finally {
            stopWatch.stop();
            log.info("total time in ms :: {} reqfilter time :: {} ",stopWatch.elapsed(TimeUnit.MILLISECONDS),timeSpent);
        }
    }