Mroonga blog


Mroonga 8.00 has been released!

Mroonga is a MySQL storage engine that supports fast fulltext search and geolocation search. It is CJK ready. It uses Groonga as a storage and fulltext search engine.

This is a major version up! But It keeps backward compatibility. You can upgrade to 8.0.0 without rebuilding database.

Mroonga 8.00 has been released!


The main changes are as follows.

  • When create hash index, tiny hash is used for reducing consumption of resources.
  • [percona57] Added gap lock detection support.

When create hash index, used tiny hash for reducing used resource

Hash index is less resouce to used from this release. Note:that rebuilding indexes are required to enable this feature for existence indexes

[percona57] Added gap lock detection support

a gap lock was being attempted while the transaction isolation level was either REPEATABLE READ or SERIALIZABLE, the following SQL error was returned to the client and no actual gap lock was taken on the affected rows.

ERROR 1105 (HY000): Using Gap Lock without full unique key in multi-table or multi-statement transactions is not allowed. You need to either rewrite queries to use all unique key columns in WHERE equal conditions, or rewrite to single-table, single-statement transaction.  Query: ALTER TABLE t ENGINE=InnoDB

From this release, as the above situation, gap lock will be taken on the affected rows.


See Release 8.00 - 2018-02-09 about detailed changes since 7.11.

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