Previously in MySQL 4.1, an Illegal mix of collations error occurred when mixing strings from same character set when one had a non-binary collation and the other a binary collation. Now the binary collation takes precedence, so that both strings are treated as having the binary collation. This restores compatibility with MySQL 4.0 behavior.

Security fix: If mysqld was started with --user=non_existent_user, it would run using the privileges of the account it was invoked from, even if that was root.

Fixed incorrect memory block allocation for the query cache in the embedded server. (Bug #9549)

Fixed a configure problem in checking for capability of performing atomic operations. (Bug #7970)

net_read_timeout and net_write_timeout were not being respected on Windows. (Bug #9721)