There are two search mechanisms available in Saleor.
The default is to use PostgreSQL. This is a fairly versatile solution that does not require any additional resources.
A more sophisticated search backend can be enabled if an Elasticsearch server is available. Elasticsearch offers a lot of advanced features, such as boosting to tune the relevance of a query or “more like this” queries. See the official Elasticsearch website to read more about its features. Please note that enabling the Elasticsearch backend does not currently enable any additional features in Saleor.
For installation and configuration instructions see Elasticsearch.