I'm not too worried about it myself, but I can see how less magic on a database server is better.
Without actually trying it, if I mix CHAR's and VARCHAR's in a table, does SHOW CREATE TABLE reflect the internal conversion? If you wanted to reduce fragmentation in an Innodb table, wouldn't all the CHAR fields need to be left-packed? For example, you'd still get fragmentation if your columns went CHAR, VARCHAR, CHAR. I guess that is unless the engine underneath did this automagically. Thanks. On Wed, 20 Oct 2004 11:29:30 +0300, Heikki Tuuri <[EMAIL PROTECTED]> wrote: > Gary, > > those 'silent column specification changes' affect all table types. That > feature has caused lots of user questions over years. It is in the TODO to > remove that feature from MySQL, because it is not standards compliant. In > InnoDB, a reason to use a CHAR column in some cases is to reduce > fragmentation if there are lots of updates to that column. A CHAR column > takes a fixed space. Silent column specification changes in many cases > defeat this optimization which would otherwise be available to users. > > Best regards, > > Heikki Tuuri > Innobase Oy > Foreign keys, transactions, and row level locking for MySQL > InnoDB Hot Backup - a hot backup tool for InnoDB which also backs up MyISAM > tables > http://www.innodb.com/order.php > > Order MySQL technical support from https://order.mysql.com/ > > .................... > > > Hey, > > From http://dev.mysql.com/doc/mysql/en/Silent_column_changes.html: > > <snip> > If any column in a table has a variable length, the entire row becomes > variable-length as a result. Therefore, if a table contains any > variable-length columns (VARCHAR, TEXT, or BLOB), all CHAR columns > longer than three characters are changed to VARCHAR columns. This > doesn't affect how you use the columns in any way; in MySQL, VARCHAR > is just a different way to store characters. MySQL performs this > conversion because it saves space and makes table operations faster. > See section 15 MySQL Storage Engines and Table Types. > </snip> > > Does this affect all table types? I'm curious if this is happening on > my InnoDB tables as well. No problems, just curiosity.. > > Thanks. > > > -- > MySQL General Mailing List > For list archives: http://lists.mysql.com/mysql > To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED] > > -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
