eZ Platform exposes very powerful Search API, allowing both Full Text search and querying the content repository using several built-in Criteria and Sort Clauses. These are supported across several search engines, allowing you to plug in another search engine without changing your code.
Available Search Engines
Currently 3 search engines exists on their own eZ Platform Bundles:
Legacy, a database-powered search engines for basic needs.
Solr, an integration providing better overall performance, much better scalability and support for more advance search capabilities RECOMMENDED
ElasticSearch, similar to Solr integration, however currently not under active development EXPERIMENTAL, NOT SUPPORTED