D.5.31 Changes in release 3.22.5

• All table lock handing is changed to avoid some very subtle deadlocks when using DROP TABLE, ALTER TABLE, DELETE FROM TABLE and mysqladmin flush-tables under heavy usage. Changed locking code to get better handling of locks of different types.
• Updated DBI to 1.00 and DBD to 1.2.0.
• Added a check that the error message file contains error messages suitable for the current version of mysqld. (To avoid errors if you accidentally try to use an old error message file.)
• All count structures in the client (affected_rows(), insert_id(), ...) are now of type BIGINT to allow 64-bit values to be used. This required a minor change in the MySQL protocol which should affect only old clients when using tables with AUTO_INCREMENT values > 16M.
• The return type of mysql_fetch_lengths() has changed from uint * to ulong *. This may give a warning for old clients but should work on most machines.
• Change mysys and dbug libraries to allocate all thread variables in one struct. This makes it easier to make a threaded `libmysql.dll' library.
• Use the result from gethostname() (instead of uname()) when constructing `.pid' file names.
• New better compressed server/client protocol.
• COUNT(), STD() and AVG() are extended to handle more than 4G rows.
• You can now store values in the range -838:59:59 <= x <= 838:59:59 in a TIME column.
• Warning: incompatible change!! If you set a TIME column to too short a value, MySQL now assumes the value is given as: [[[D ]HH:]MM:]SS instead of HH[:MM[:SS]].
• TIME_TO_SEC() and SEC_TO_TIME() can now handle negative times and hours up to 32767.
• Added new option SET SQL_LOG_UPDATE={0|1} to allow users with the PROCESS privilege to bypass the update log. (Modified patch from Sergey A Mukhin violet@rosnet.net.)
• Fixed fatal bug in LPAD().
• Initialise line buffer in `mysql.cc' to make BLOB reading from pipes safer.
• Added -O max_connect_errors=# option to mysqld. Connect errors are now reset for each correct connection.
• Increased the default value of max_allowed_packet to 1M in mysqld.
• Added --low-priority-updates option to mysqld, to give table-modifying operations (INSERT, REPLACE, UPDATE, DELETE) lower priority than retrievals. You can now use {INSERT | REPLACE | UPDATE | DELETE} LOW_PRIORITY ... You can also use SET SQL_LOW_PRIORITY_UPDATES={0|1} to change the priority for one thread. One side effect is that LOW_PRIORITY is now a reserved word. :(
• Add support for INSERT INTO table ... VALUES(...),(...),(...), to allow inserting multiple rows with a single statement.
• INSERT INTO tbl_name is now also cached when used with LOCK TABLES. (Previously only INSERT ... SELECT and LOAD DATA INFILE were cached.)
• Allow GROUP BY functions with HAVING:

  mysql> SELECT col FROM table GROUP BY col HAVING COUNT(*)>0;
  

• mysqld will now ignore trailing `;' characters in queries. This is to make it easier to migrate from some other SQL servers that require the trailing `;'.
• Fix for corrupted fixed-format output generated by SELECT INTO OUTFILE.
• Warning: incompatible change! Added Oracle GREATEST() and LEAST() functions. You must now use these instead of the MAX() and MIN() functions to get the largest/smallest value from a list of values. These can now handle REAL, BIGINT and string (CHAR or VARCHAR) values.
• Warning: incompatible change! DAYOFWEEK() had offset 0 for Sunday. Changed the offset to 1.
• Give an error for queries that mix GROUP BY columns and fields when there is no GROUP BY specification.
• Added --vertical option to mysql, for printing results in vertical mode.
• Index-only optimisation; some queries are now resolved using only indexes. Until MySQL 4.0, this works only for numeric columns. See section 5.4.3 How MySQL Uses Indexes.
• Lots of new benchmarks.
• A new C API chapter and lots of other improvements in the manual.

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