Functionality added or changed in MySQL 4.0.14

                

* A documentation change: Function `INTERVAL(NULL, ...)' returns `-1'.



* Enabled `INSERT' from `SELECT' when the table into which the records are inserted is also a table

listed in the `SELECT'.



* Allow `CREATE TABLE' and `INSERT' from any `UNION'.



* The `SQL_CALC_FOUND_ROWS' option now always returns the total number of rows for any `UNION'.



* Removed `--table' option from `mysqlbinlog' to avoid repeating `mysqldump' functionality.



* Changed optimiser slightly to prefer index lookups over full table scans.



* Added thread-specific `max_seeks_for_key' variable that can be used to force the optimiser to use 

keys instead of table scans even if the cardinality of the index is low.



* Added optimisation that converts `LEFT JOIN' to normal join in some cases.



* A documentation change: added a paragraph about failover in replication (how to use a surviving 

slave as the new master, how to resume to the original setup). *Note Replication FAQ::.



* A documentation change: added warning notes about safe use of the `CHANGE MASTER' command. *Note CHANGE MASTER TO::.



* MySQL now issues a warning (not an error, as in 4.0.13) when it opens a table that was created with MySQL 4.1.



* Added `--nice' option to `mysqld_safe' to allow setting the niceness of the `mysqld' process. 



* Added `--read-only' option to cause `mysqld' to allow no updates except from slave threads or from users with the `SUPER' privilege.



* `SHOW BINLOG EVENTS FROM x' where `x' is strictly less than 4 now silently converts `x' to 4 instead 

of printing an error. The same change was done for `CHANGE MASTER TO MASTER_LOG_POS=x' and `CHANGE MASTER TO RELAY_LOG_POS=x'.



* `mysqld' now only adds an interrupt handler for the `SIGINT' signal if you start it with the new `--gdb' 

option.  This is because some MySQL users encountered strange problems when they accidentally sent `SIGINT' to `mysqld' threads.



* `RESET SLAVE' now clears the `Last_errno' and `Last_error' fields in the output of `SHOW SLAVE STATUS'.



* Added `max_relay_log_size' variable; the relay log will be rotated automatically when its size exceeds 

`max_relay_log_size'. But if `max_relay_log_size' is 0 (the default), `max_binlog_size' will be used (as in older versions). 

`max_binlog_size' still applies to binary logs in any case.



* `FLUSH LOGS' now rotates relay logs in addition to the other types of logs it already rotated.