mysql - Two InnoDB table Join taking a Day!! I can't use the MYISAM because my table goes over the MaxData Length. How to solve this problem? -

i have 2 tables(innodb) 1 15 million records , other 14 million records , need left join on these tables based on 'title reference'. i'm using innodb table may need add more data resulting table in future. query has been going on since yesterday.

this 'title_reference' varchar(20), not primary key there no duplicates in either tables.

i have been checking table status , it's being updated approximately every 2 hours. mean query active?

i have 15 million table first in order while doing join.

where making mistake? how solve problem?

if fields you're joining on not indexed - , query written correctly uses index - that's going take long time sure. make sure indexed , query uses them (using explain ), , might want tuning - subject entirely - mysql server's configuration handle large tables - bigger key buffer, example, useful.