title: Yii2 set and get cache value using memcache
body: <p>I'm trying to get the cache value by key, in this case the value is "count". But sometimes I get the value and sometimes not. The lenght of the key is same. Where is problem? </p>
  
  <pre><code>   $cache = Yii::$app-&gt;cache;
  
      $q=  Yii::$app-&gt;getSecurity()-&gt;generateRandomString(24) . time() ;
      $key = 'captcha_value_' . $q;
  
      $cache-&gt;set($key, 'count');
  
      echo "&lt;br/&gt;$key: ".$cache-&gt;get($key)."";
  </code></pre>
  
  <p>that's what is output</p>
  
  <pre><code>     captcha_value_DgytIGlX-tagsEFzoDjcK5ao1574253702:count 
       captcha_value_6qNykCcw91KCSD2lJ0Trl_cY1574254788:
  </code></pre>