[8.x] Implement Full-Text Search for PostgreSQL

[tpetry]

I worked with @driesvints on a basic api for the query builder to do fulltext searching (#40129). Based on the agreed api and his implementation for MySQL, I was able to easily add PostgreSQL support:

Schema::create('articles', function (Blueprint $table) {
    $table->id('id');
    $table->string('title', 200);
    $table->text('body');
    $table->fulltext(['title', 'body']);
});

// Search for "databases" in the title and body fulltext index...
$articles = DB::table('articles')
    ->whereFulltext(['title', 'body'], 'database')
    ->get();

// Search for "databases" in the title and body fulltext index with german language...
$articles = DB::table('articles')
    ->whereFulltext(['title', 'body'], 'database', ['language' => 'german'])
    ->get();

// Search for "databases" in the title and body fulltext index with phrase-mode...
$articles = DB::table('articles')
    ->whereFulltext(['title', 'body'], 'database', ['mode' => 'phrase'])
    ->get();

// Search for "databases" in the title and body fulltext index with websearch-mode...
$articles = DB::table('articles')
    ->whereFulltext(['title', 'body'], 'database', ['mode' => 'websearch'])
    ->get();

PostgreSQL has the great functionality that you can fine tune fulltext-search very much. For the moment, I only implemented the different search-term parsers to keep the pull request small. You will have access to the following search-term modes:

• mode = 'plain': The plainto_tsquery function will transform a search string by and-ing the search terms: plainto_tsquery('english', 'The Fat Rats door') --> must match 'fat' & 'rat' & 'door'
• mode = 'phraseto': The phraseto_tsquery function will transform a search string by needing the phrases to appear in the exact order one after another: phraseto_tsquery('english', 'The Fat Rats door') --> must match 'fat' <-> 'rat' <-> 'door'
• mode = 'websearch': The websearch_to_tsquery function is mostly like MySQL's boolean search mode, which allows positive/negative operators in the text. But contrary to MySQL the terms are combined with and instead of or: websearch_to_tsquery('english', 'fat +rat -door') --> must match 'fat' & 'rat' & !'door'

The websearch mode mode = 'websearch' is only available in PostgreSQL 11+ so the standard mode has been set to mode = 'plain'.

In my pull request #39875 I added fulltext index support for PostgreSQL which was released with v8.75.0. I did not implement multiple columns as the there are different ways to build them and querying needs to use the same method as the index. With querying support now added, I also implemented multiple columns support.

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This is a stacked Pull Request on #39875, i will rebase it to the 8.x branch as soon as the pull request of @driesvints is merged.

[foremtehan]

Can we leverage PostgreSQL GIN index for this or it will be useless ?

[tpetry]

Can we leverage PostgreSQL GIN index for this or it will be useless ?

If you set a fulltext() index on the columns it will be used 😉

[driesvints]

Converting to draft for now until my own PR is merged. Thanks!

[driesvints]

Actually, @tpetry can you send this to my own branch instead? Thanks!

[driesvints]

Nvm, got it. Thanks @tpetry!