index-aliases.md

Index aliases

Aliases allow you to use an index under a different name.This very useful for zero downtime deployments.

There are three aliases created: a read alias, a write alias and a history alias. The read alias is used for reading, the write index is used for writing. The history aggregates all old indices, which can be pruned. When updating an index it is recreated to a new index with a unique name. The "write" alias is pointed to the new index and all Scout updates will be forwarded to the "write" index. After all entities are imported the "read" alias will also be pointed to the new index.

If you wish to keep the old indices set prune_old_aliases to false in config/elasticvision.php

Using aliases

A model is only using index aliases if it implements the Aliased interface or enabled in the configuration (see mapping).

After that, any time you use the scout:import command a new index will be created and when the insertion of models is done the alias will be pointed to the new index.

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;
use Hilsonxhero\ElasticVision\Application\Explored;
use Hilsonxhero\ElasticVision\Application\Aliased;
use Laravel\Scout\Searchable;

class Post extends Model implements Explored, Aliased
{
    use HasFactory;
    use Searchable;

    //...
}

return [
    'indexes' => [
        'posts' => [
            'aliased' => true,
            'properties' => [
                'id' => 'keyword',
                'title' => 'text',
                'created_at' => 'date',
                'published' => 'boolean',
                'author' => 'nested',
            ],
        ],
    ],
];

Be aware that if you currently already have indices and would like to move to using aliases you will need to delete those indices before configuring the aliases. In Elasticsearch a given name can only be either an index or alias, not both and this cannot be changed on-the-fly.