Please read [`hook_views_query_alter()`][1] API, which say:

> This hook should be placed in `MODULENAME.views.inc` and it will be auto-loaded. `MODULENAME.views.inc` must be in the directory specified by the 'path' key returned by `MODULENAME_views_api()`, or the same directory as the `.module file`, if 'path' is unspecified.

So double check that you're placing the hook in the correct place either in the main module file or `MODULENAME.views.inc` (not `mymodule_views.inc`) and make sure that you've `MODULENAME_views_api` function defined (unless it's already defined by Feature). After all that clear your all caches (including memcached if in it's in use).

See also: [How do I use hook_views_query_alter()?][2]

If there is still a problem, that means your view is implementing different query handler and possibly it implements `views_plugin_query` (which by default doesn't provide any alter code), so you have to find the right plugin query handler (a query class) and see which hooks they're using instead.

To find which plugin is in use.

Method 1: If view is already exported, check `base_table` name and which module is dealing with that table. If it's `search_api_`, then it's Search API module.

Method 2: Edit `views/includes/view.inc`, find the code which executes the query alter: `$this->query->alter($this);` and dump the `$this->query` object to see what class is used for that view.

Then find that class and its `alter()` method to see how it's implemented.

Here are few examples:

Views (`class views_plugin_query_default extends views_plugin_query`):

    function alter(&$view) {
      foreach (module_implements('views_query_alter') as $module) {
        $function = $module . '_views_query_alter';
        $function($view, $this);
      }
    } 

Search API (`class SearchApiViewsQuery extends views_plugin_query`):

    public function alter(&$view) {
      parent::alter($view);
      drupal_alter('search_api_views_query', $view, $this);
    }

YQL Views (`class yql_views_query_plugin_query_yql extends views_plugin_query`):

    function alter(&$view) {
      foreach (module_implements('yql_views_query_query_alter') as $module) {
        $function = $module . '_yql_views_query_query_alter';
        $function($view, $this);
      }
    }

So as you can see, you need to use different hooks for different views types.

In your particular case `collection_products` views is handled by Search API, so you need to define `hook_search_api_views_query_alter` instead.

  [1]: https://api.drupal.org/api/views/views.api.php/function/hook_views_query_alter/7
  [2]: https://drupal.stackexchange.com/q/3869/1908