Hi, Kazuhiko! On Dec 02, Kazuhiko Shiozaki wrote: > Hello ! > > I am investigating a slow query and have a question about execution plan > with mroonga (possibly any storage engine?). > (with MariaDB 10.0.15.)
> CREATE TABLE catalog_full_text ( > uid bigint(20) unsigned NOT NULL, > title varchar(255) COLLATE utf8_unicode_ci DEFAULT '', > PRIMARY KEY (uid), > FULLTEXT KEY title (title) COMMENT 'parser > "TokenBigramSplitSymbolAlphaDigit"' unrelated comment: in MariaDB it's *much* better to use engine-defined table attributes for this. https://mariadb.com/kb/en/engine-defined-new-tablefieldindex-attributes/ > ) ENGINE=Mroonga DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci; ... > Accoding to Kohei, a Mroonga developer, we always have 'rows = 1' for > mroonga full-text query because MariaDB does not request such value to > mroonga (JOIN::get_examined_rows() in sql/sql_select.cc) Correct. > So here are my questions : > > * can MariaDB request an 'estimation of rows' to mroonga (or whatever > storage engine) ? > * can such information help to decide a better execution plan with > INNER JOIN like above ? Yes, I believe it is possible. I've reported this issue as a bug now: https://mariadb.atlassian.net/browse/MDEV-7250 Regards, Sergei _______________________________________________ Mailing list: https://launchpad.net/~maria-developers Post to : [email protected] Unsubscribe : https://launchpad.net/~maria-developers More help : https://help.launchpad.net/ListHelp
