Add warning about MySQL collation
Fix database index length
This allows new databases to be created with utf8mb4, on MySQL. The maximum
column size is 767 bytes. Each character is 4 bytes long -> 767 / 4 = 191
characters for the column.
The limit down to 127 is needed cause of a long time bug in mysql. The
error message looks like this when creating an index.
Mysql2::Error: Specified key was too long; max key length is 1000 bytes
So with utf8 (3 bytes for one char) you exceed this with two
varchar(255).
See http://bugs.mysql.com/bug.php?id=4541 guru meditation
Signed-off-by: Andreas Schneider <asn@cryptomilk.org>
The limit down to 127 is needed cause of a long time bug in mysql. The
error message looks like this when creating an index.
Mysql2::Error: Specified key was too long; max key length is 1000 bytes
So with utf8 (3 bytes for one char) you exceed this with two
varchar(255).
See http://bugs.mysql.com/bug.php?id=4541
