# About Mroonga

Mroonga is a full-text search storage engine based on Groonga, which is an open-source CJK-ready (Chinese, Japanese, and Korean) fulltext search engine using column base. See [groonga.org](https://groonga.org) for more.

With Mroonga, you can have a CJK-ready full text search feature, and it is faster than the [MyISAM](https://mariadb.com/docs/server/server-usage/storage-engines/myisam-storage-engine) and [InnoDB](https://mariadb.com/docs/server/server-usage/storage-engines/innodb) [full text search](https://mariadb.com/docs/server/ha-and-performance/optimization-and-tuning/optimization-and-indexes/full-text-indexes) for both updating and searching.

Mroonga also supports Groonga's fast geolocation search by using MariaDB's geolocation SQL syntax.

Mroonga only supports Linux x86\_64 (Intel64/AMD64).

## How to Install

Enable Mroonga with the following statement:

```sql
INSTALL SONAME 'ha_mroonga';
```

On Debian and Ubuntu mroonga engine are installed with

```bash
sudo apt-get install mariadb-plugin-mroonga
```

See [Plugin overview](https://mariadb.com/docs/server/reference/plugins/plugin-overview) for details on installing and uninstalling plugins.

[SHOW ENGINES](https://mariadb.com/docs/server/reference/sql-statements/administrative-sql-statements/show/show-engines) can be used to check whether Mroonga is installed correctly:

```sql
SHOW ENGINES;
...
*************************** 8. row ***************************
      Engine: Mroonga
     Support: YES
     Comment: CJK-ready fulltext search, column store
Transactions: NO
          XA: NO
  Savepoints: NO
...
```

Once the plugin is installed, add a UDF (User-Defined Function) named "last\_insert\_grn\_id", that returns the record ID assigned by groonga in INSERT, by the following SQL.

```sql
CREATE FUNCTION last_insert_grn_id RETURNS INTEGER SONAME 'ha_mroonga.so';
```

## Limitations

* The maximum size of a single key is 4096 bytes.
* The maximum size of all keys is 4GB.
* The maximum number of records in a fulltext index is 268,435,455
* The maximum number of distinct terms in a fulltext index is 268,435,455
* The maximum size of a fulltext index is 256GB

Note that the maximum sizes are not hard limits, and may vary according to circumstance.

For more details, see [limitations.html](https://mroonga.org/docs/reference/limitations.html).

## Available Character Sets

Mroonga supports a limited number of [character sets](https://mariadb.com/docs/server/reference/data-types/string-data-types/character-sets). These include:

* ASCII
* BINARY
* CP932
* EUCJPMS
* KOI8R
* LATIN1
* SJIS
* UJIS
* UTF8
* UTF8MB4

## More Information

Further documentation for Mroonga can be found at

<sub>*This page is licensed: CC BY-SA / Gnu FDL*</sub>

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