Can you recommend a PHP library that functions as a search engine, similar to Sphinx but without requiring installation on the server and compatible with various hosting services?

Consider using Zend_Search_Lucene as an alternative, but be aware of its feature of keeping index files open during write operations for better performance.

keep in mind any potential compatibility issues with your hosting provider when selecting a search engine library. In the case of Zend_Search_Lucene, it may work well with some hosting providers but not with others due to limits on the number of simultaneously open files. Be sure to thoroughly test and evaluate any library before implementing it into your project.

If the previous options do not meet your needs, you can consider using my search engine. Although it was written three years ago, it is still a viable option, offering stemming and MySQL integration.

When exploring different search engine libraries, it's important to evaluate them thoroughly and consider all available options before making a decision. In this case, my search engine could be worth considering, especially if you require features such as stemming and MySQL integration. It's also worth checking out similar libraries, such as phpmorphy, to see which one best fits your needs.

If you cannot use PostgreSQL or install Sphinx, consider utilizing the Google Search API for site searches.