My new Wordpress database all the Wordpress created tables use InnoDB engine and plugin created table use MyISAM. But older site database all the tables use MyISAM table engine. I use MySQL 5.5.35-cll i686.

If I use two different table engines in a same database, it will reduce my site performance or are there any downside?

  • What's the MySQL version? Commented Feb 16, 2014 at 23:39
  • The downside is that some of your tables are still in MyISAM. Commented Feb 17, 2014 at 4:10
  • @ Sparkot, i have update the post.
    – MaxBro57
    Commented Feb 17, 2014 at 15:34
  • @ Bill, Thanks bill. You mean it's better go for InnoDB?
    – MaxBro57
    Commented Feb 17, 2014 at 16:10
  • 2
    Yes, InnoDB supports ACID, data recovery, transactions, foreign keys, row-level locking -- none of which are supported by MyISAM. Also in modern versions of MySQL, InnoDB is faster and more scalable than MyISAM under most typical scenarios. Commented Feb 18, 2014 at 1:54

1 Answer 1


Having InnoDB won't make MyISAM slower and vice versa. However you have to be more careful in memory allocation for InnoDB and MyISAM. Because they store data and indexes in different buffers. MyISAM:

  • Indexes in the key buffer
  • Data in file system cache


  • Data and indexes (well, in InnoDB everything is indexes) in the buffer pool

So if you allocate more than necessary to InnoDB then MyISAM will have to access disk more often (and vice versa)

  • Thanks akuzminsky. So is it wise idea to convert rest of the tables to InnoDB engine?
    – MaxBro57
    Commented Feb 17, 2014 at 15:31
  • Unless there is a very good reason for MyISAM (e.g. need for full text indexes etc) I tend to recommend InnoDB. It's been very actively developing and at the moment is much better than MyISAM from point of view of reliability, performance, flexibility in tuning. Even from data recovery standpoint(yes, unfortunately that happens too) chance to get your data back is way too bigger with InooDB than with MyISAM
    – akuzminsky
    Commented Feb 17, 2014 at 15:58
  • Again thanks akuzminsky. I saw that some plugins display InnoDB fragmented. But when i try to optimize that table it's not success. Is it a normal?
    – MaxBro57
    Commented Feb 17, 2014 at 16:05
  • well, I'm not sure what plugins you mean. I know you can check InnoDB tablespace fragmentation with XtraBackup (percona.com/doc/percona-xtrabackup/2.1/xtrabackup_bin/…) . And yes, OPTIMIZE TABLE will rebuild a table, thus will defragment it. Not sure why it fails though.
    – akuzminsky
    Commented Feb 17, 2014 at 16:21
  • I use wpxtram. I think it's better contact the developer. Again thank you so much.
    – MaxBro57
    Commented Feb 17, 2014 at 16:32

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