If you try to perform full-text searches in a document in the Chinese, Japanese, or Korean languages, you will notice that it either doesn't work very well or not at all.

The default full-text search feature uses spaces to separate words in a document. However, these languages usually do not use spaces as delimiters. As a result, standard full-text search engines are ineffective with the CJK languages. Moreover, these languages contain many words with less than four characters. So, the standard search method is not adapted at all, as it ignores short words with four or less characters by default.

A project was started in 2008 to try and solve this problem. The project was called Senna, and it tried to add Japanese language support to the full-text search feature of MySQL.

From 2011 onwards, a new project called Groonga, presented as the successor of Senna, started providing regular releases of a generic library that provides connections to different DBMSs. Mroonga is the MySQL storage...