When enabling max-idx-128 MySQL files to create the initial database when running "emerge --config =dev-db/mysql-5.1.50-r1", it dies in the middle of the creation of the tables and leaves the installation unusable.
The problem affects also mysql_upgrade, which will render a broken database whcih may not work with older versions of MySQL (as 5.0).
Steps to Reproduce:
1. USE="max-idx-128" emerge mysql
2. emerge --config =dev-db/mysql-5.1.50-r1
mysql_install_db fails to create the complete mysql database.
A completly working mysql database is created.
There is at least one bug about the max-idx-128 in the mysql bugzilla (see http://bugs.mysql.com/bug.php?id=36751).
I do suggest that the USE option max-idx-128 would be disabled for MySQL 5.1 until this bug has been fixed in the upstream 5.1/5.5 tree.
When building mysql 5.1 with debug and max-idx-128 USE options and in my.cnf enable
log = /tmp/mysqld.sql
debug = d:t:i:o,/tmp/mysqld.trace
you will find in your /var/log/mysql/mysqld.log
mysqld: my_bitmap.c:366: bitmap_intersect: Assertion `map->bitmap && map2->bitmap' failed.
Explicitly blocked in the eclass for now.
We can't just disable it by default, as that would make existing idx-128 data inaccessible.
Please reopen upstream.