MySQL 5.6 RC: further thoughts and questions

Here are a few questions I came up with while experimenting with MySQL 5.6.7 & 5.6.8. They are the impressions of a first-time encounter with 5.6, which is a single opportunity for a person to point out the things that strike as odd.

Bugs-wise, just submitted another crashing bug for 5.6.8. I’m just one man, so I extrapolate to realize there is still much work to be done.

The below list does not necessarily make for a bug list; mostly things that puzzle me. I hope it can stir some additional thinking.

  1. Transportable tablespace: what’s the difference between FLUSH TABLES my_table WITH READ LOCK and FLUSH TABLES my_table FOR EXPORT? Both create the .cfg file, and both seem to operate just as well. One document says READ LOCK, another says FOR EXPORT.
  2. What’s the ALGORITHM=? flag in online ALTER TABLE? Apparently one can write to altered table even on ALGORITHM=COPY. There’s not enough documentation to explain.
  3. How come there’s not a single example of online InnoDB DDL in official docs?
  4. Why the inconsistency of putting ALGORITHM=…, LOCK=… in between commas, as opposed to other flags/commands not between commas? For example: ALTER TABLE my_table ADD COLUMN i INT, ALGORITHM=COPY, LOCK=SHARED, ENGINE=InnoDB ROW_FORMAT=COMPRESSED KEY_BLOCK_SIZE=4
  5. Why would anyone care about FULLTEXT search word proximity by bytes? Typically, one would want proximity by words. I can find the excuse for proximity by characters. By bytes? A user is not interested in the low level representation of the text!
  6. Could we get a distinct tablespace for the mysql internal InnoDB tables? (I understand there’s a separate tablespace for UNDO logs)
  7. Why the need to configure gtid_mode=ON as well as disable-gtid-unsafe-statements so as to enable GTID replication? If only the first is set, an error is produced upon CHANGE MASTER TO MASTER_AUTO_POSITION=1
  8. And when said error is produced, why does it not mention disable-gtid-unsafe-statements, and instead read out a cryptic message? Also note this post by Giuseppe Maxia.

12 thoughts on “MySQL 5.6 RC: further thoughts and questions

  1. @Lars,

    Moreover, now I see it is impossible to start MySQL with only gtid_mode=ON, whereus in my previous test it was possible to do so, and error was only reported on CHANGE MASTER TO.
    This is also an improvement and avoids confusion.

  2. Hi Shlomi,

    Thanks for the feedback! re #5, agree that it is a design flaw and we intend to fix it.

Leave a Reply

Your email address will not be published.

This site uses Akismet to reduce spam. Learn how your comment data is processed.