# Advanced configuration

## Facets

## Multiple indexes

Multiple indexes can be created and searched independently, but if you wish to override an existing
index with another, you can use the `$hide_ancestor` config.

```php
use SilverStripe\Assets\File;
use My\Namespace\Index\MyIndex;

class MyReplacementIndex extends MyIndex
{
    private static $hide_ancestor = MyIndex::class;

    public function init()
    {
        parent::init();

        $this->addClass(File::class);
        $this->addFulltextField('Title');
    }
}
```

You can also filter all indexes globally to a set of pre-defined classes if you wish to
prevent any unknown indexes from being automatically included.

```yaml
SilverStripe\FullTextSearch\Search\FullTextSearch:
  indexes:
    - MyReplacementIndex
    - CoreSearchIndex
```

## Synonyms

## Spell check

## Boosting/Weighting
 
 Results aren't all created equal. Matches in some fields are more important
 than others; for example, a page `Title` might be considered more relevant to the user than terms in the `Content` field.
 
 To account for this, a "weighting" (or "boosting") factor can be applied to each searched field. The default value is `1.0`, anything below that will decrease the relevance, anything above increases it.
 
 To adjust the relative values, pass them in as the third argument to your `addSearchTerm()` call:
 
 ```php
 use My\Namespace\Index\MyIndex;
 use SilverStripe\FullTextSearch\Search\Queries\SearchQuery;
 use Page;
 
 $query = SearchQuery::create()
     ->addSearchTerm(
         'fire',
         null, // don't limit the classes to search
         [
             Page::class . '_Title' => 1.5,
             Page::class . '_Content' => 1.0,
             Page::class . '_SecretParagraph' => 0.1,
         ]
     );
 $results = singleton(MyIndex::class)->search($query);
 ```
 
 This will ensure that `Title` is given higher priority for matches than `Content`, which is well above `SecretParagraph`.

## Indexing related objects

## Subsites

## Adding new fields