InnoDB Small update very slow, performance issue

Question

I have an update script which update my database every night.

It's a small database ~10k items. The update is fast for each table but one. It's very slow on a join table.

The join table is a link between Item table and Type table as following :

Item.Code <-> JoinTable.RefCode (VARCHAR 30), JoinTable.IdType(int 11) <-> Type.id

The engine is InnoDB. There are two foreign keys on the referenced tables and a unique key on the two columns. Also, indexes on each column in order to allow foreign keys.

I'm using the following SQL query to update the table :

INSERT INTO JoinTable (id, RefCode, IdType)
   VALUES ( NULL, "AAA", 9584 )
ON DUPLICATE KEY UPDATE
   id = LAST_INSERTED_ID(id),
   refCode = values(refCode),
   refType = values(refType)

So, the main problem it runs for about 30 MINUTES for 15k referenced id's.

When I use MyISAM engine it's about 2 sec. but there is no more foreign keys.

I understand that MyISAM delete foreign keys and it's faster but I think 30 min for a so small database is far from normal.

Could you help me increase performances please ?

Answer 1

Edit the InnoDB settings in your MySQL configuration and restart the MySQL daemon. They all start with "innodb_" and will have explanations of their purpose.

I changed the innodb_buffer_pool_size and innodb_log_file_size.

Answer 2

Change the insert to use IGNORE, and try without the VALUES()

   INSERT IGNORE INTO JoinTable (id, RefCode, IdType)
   VALUES ( NULL, "AAA", 9584 )        
   ON DUPLICATE KEY UPDATE
   id = LAST_INSERTED_ID(id),
   refCode = refCode,
   refType = refType

It could also be that your innodb buffer size is to small.