Speeding up a soap powered website

Question

Hi all,

We're currently looking into doing some performance tweaking on a website which relies heavily on a Soap webservice. But ... our servers are located in Belgium and the webservice we connect to is locate in San Francisco so it's a long distance connection to say the least.

Our website is PHP powered, using PHP's built in SoapClient class. On average a call to the webservice takes 0.7 seconds and we are doing about 3-5 requests per page. All possible request/response caching is already implemented so we are now looking at other ways to improved the connection speed.

This is the code which instantiates the SoapClient, what i'm looking for now is other ways/methods to improve speed on single requestes. Anyone has idea's or suggestions?

private function _createClient()
{
    try {

        $wsdl = sprintf($this->config->wsUrl.'?wsdl', $this->wsdl);
        $client = new SoapClient($wsdl, array(
            'soap_version'       => SOAP_1_1,
            'encoding'           => 'utf-8',
            'connection_timeout' => 5,
            'cache_wsdl'         => 1,
            'trace'              => 1,
            'features'           => SOAP_SINGLE_ELEMENT_ARRAYS
        ));

        $header_tags = array('username' => new SOAPVar($this->config->wsUsername, XSD_STRING, null, null, null, $this->ns),
                             'password' => new SOAPVar(md5($this->config->wsPassword), XSD_STRING, null, null, null, $this->ns));
        $header_body = new SOAPVar($header_tags, SOAP_ENC_OBJECT);
        $header = new SOAPHeader($this->ns, 'AuthHeaderElement', $header_body);

        $client->__setSoapHeaders($header);

    } catch (SoapFault $e){
        controller('Error')->error($id.': Webservice connection error '.$e->getCode());
        exit;
    }

    $this->client = $client;
    return $this->client;
}

Answer 1

PHP.INI

output_buffering = On
output_handler = ob_gzhandler
zlib.output_compression = Off

Answer 2

So, the root problem is number of request you have to do. What about creating grouped services ?

• If you are in charge of the webservices, you could create specialized webservices which do multiple operations at the same time so your main app can just do one request per page.
• If not you can relocate your app server near SF.
• If relocating all the server is not possible and you can not create new specialized webservices, you could add a bridge, located near the webservices server. This bridge would provide the specialized webservices and be in charge of calling the atomic webservices. Instead of 0.7s * 5 you'd have 0.7s + 5 * 0.1 for example.

Answer 3

1 You can assert your soap server use gzip compression for http content, as well as your site output does. A 0,7s roundup to SF seems a bit long, it's either webservice is long to answer, either there is an important natwork latency. If you can, give a try to other hosting companies for your belgium server, in France some got a far better connectivity to the US than others. I experienced to move a website from one host o another and network latency between Paris and New york has almost doubled ! it's uge and my client with a lot of US visitors was unhappy with it. The solution of relocating web server to SF can be an option, you'll get a far better connectivity between servers, but be careful of latency if your visitors are mainly located in Europe.

2 You can use an opcode cache mecanism, such as xcache or APC. It wil not change the soap latency, but will improve php execution time.

3 Depending if soap request are repetitive, and how long could a content update could be extended, you can give it a real improvement using cache on soap results. I suggest you to use in-memory caching system (Like xcache/memcached or other) because they're ay much faster than file or DB cache system.

From your class, the createclient method isn't the most adapted exemple functionality to be cached, but for any read operation it's just the best way to perf :

private function _createClient()
{
  $xcache_key = 'clientcache'
  if (!xcache_isset($key)) {
      $ttl = 3600; //one hour cache lifetime
      $client = $this->_getClient(); ///private method embedding your soap request          
      xcache_set($xcache_key, $client, $ttl);
      return $client;
   }
   //return result form mem cache
   return xcache_get($xcache_key);
}

The example is for xcache extension, but you can use other systems in a very similar manner

4 To go further you can use similar mecanism to cache your php processing results (like template rendering output and other ressource consumming operations). The key to success with this technic is to know exactly wich part is cached and for how long it will stay withous refreshing.

Answer 4

Do you know for sure that it is the network latency slowing down each request? 0.7s seems a long round time, as Benoit says. I'd look at doing some benchmarking - you can do this with curl, although I'm not sure how this would work with your soap client.

Something like:

$ch = curl_init('http://path/to/sanfrancisco/');
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$output = curl_exec($ch);
$info = curl_getinfo($ch);

$info will return an array including elements for total_time, namelookup_time, connect_time, pretransfer_time, starttransfer_time and redirect_time. From these you should be able to work out whether it's the dns, request, the actual soap server or the response that's taking up the time.

One obvious thing that's just occurred to me is are you requesting the SOAP server via a domain or an IP? If you're using a domain, your dns might be slowing things down significantly (although it will be cached at several stages). Check your local dns time (in your soap client or php.ini - not sure) and the TTL of your domain (in your DNS Zone). Set up a static IP for your SanFran server and reference it that way if not already.

Answer 5

Optimize the Servers (not the client!) HTTP responce by using caching and HTTP compressing. Check out the hits at yahoo http://developer.yahoo.com/performance/rules.html

Answer 6

Any chance of using an AJAX interface.. if the requests can be happening in the background, you will not seem to be left waiting for the response.