Functionality Added or Changed
A new CMake option,
MYSQL_PROJECT_NAME, can be set on
Windows or Mac OS X to be used in the project name.
ucs2_general_mysql500_ci collations have been
added that preserve the behavior of
ucs2_general_ci from versions of MySQL
previous to 5.1.24. Bug #27877 corrected an error in the
original collations but introduced an incompatibility for
columns that contain German
'ß' LATIN SMALL
LETTER SHARP S. (As a result of the fix, that character compares
equal to characters with which it previously compared
different.) A symptom of the problem after upgrading to MySQL
5.1.24 or newer from a version older than 5.1.24 is that
CHECK TABLE produces this error:
Table upgrade required. Please do "REPAIR TABLE `t`" or dump/reload to fix it!
REPAIR TABLE could
not fix the problem. The new collations permit older tables
created before MySQL 5.1.24 to be upgraded to current versions
To convert an affected table after a binary upgrade that leaves
the table files in place, alter the table to use the new
collation. Suppose that the table
one or more problematic
utf8 columns. To
convert the table at the table level, use a statement like this:
ALTER TABLE t1 CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_mysql500_ci;
To apply the change on a column-specific basis, use a statement
like this (be sure to repeat the column definition as originally
specified except for the
ALTER TABLE t1 MODIFY c1 CHAR(N) CHARACTER SET utf8 COLLATE utf8_general_mysql500_ci;
To upgrade the table using a dump and reload procedure, dump the
table using mysqldump, modify the
CREATE TABLE statement in the
dump file to use the new collation, and reload the table.
After making the appropriate changes,
TABLE should report no error.
For more information, see Checking Whether Tables or Indexes Must Be Rebuilt, and Rebuilding or Repairing Tables or Indexes. (Bug #43593, Bug #11752408)
Memory allocation for
InnoDB tables was
reorganized to reduce the memory overhead for large numbers of
tables or partitions, avoiding situations where the
“resident set size” could grow regardless of
FLUSH TABLES statements. The problem was most
evident for tables with large row size. Some of the memory that
was formerly allocated for every open table is now allocated
only when the table is modified for the first time.
(Bug #11764622, Bug #57480)
Incompatible Change: An earlier change (in MySQL 5.1.59 and 5.5.16) was found to modify date-handling behavior in General Availability-status series (MySQL 5.1 and 5.5). This change has been reverted.
The change was that several functions became more strict when
DATE() function value as
their argument, thus they rejected incomplete dates with a day
part of zero. These functions were affected:
YEARWEEK(). The previous behavior
has been restored.
A Valgrind error was fixed in the function
The server could crash when creating an
InnoDB temporary table under Linux, if the
$TMPDIR setting points to a
tmpfs filesystem and
enabled, as it is by default in MySQL 5.5.4 and higher. The
entry in the error log looked like:
101123 2:10:59 InnoDB: Operating system error number 22 in a file operation. InnoDB: Error number 22 means 'Invalid argument'.
The crash occurred because asynchronous I/O is not supported on
tmpfs in some Linux kernel versions. The workaround was to turn
innodb_use_native_aio setting or use
a different temporary directory. The fix causes
InnoDB to turn off the
innodb_use_native_aio setting automatically
if it detects that the temporary file directory does not support
(Bug #13593888, Bug #11765450, Bug #58421)
InnoDB: The MySQL server could halt with an assertion error:
InnoDB: Failing assertion: page_get_n_recs(page) > 1
Subsequent restarts could fail with the same error. The error
occurred during a purge
operation involving the
change buffer. The
workaround was to set the configuration option
(Bug #13413535, Bug #61104)
References to C preprocessor symbols and macros
UNIV_SET_MEM_TO_ZERO were removed from the
InnoDB source code. They were only used in
debug builds instrumented for Valgrind. They are replaced by
calls to the
With 1024 concurrent
running concurrently and the
CREATE TABLE operation
InnoDB table could fail. The
.ibd file from the failed
TABLE was left behind, preventing the table from being
created later, after the load had dropped.
The fix adds error handling to delete the erroneous
.ibd file. This error was less likely to
occur in MySQL 5.5 and 5.6, because raising the number of
InnoDB undo slots increased the number of
simultaneous transactions needed to trigger the bug, from 1K to
When copying a partitioned
InnoDB table from
a Linux system to a Windows system, you could encounter this
101115 14:19:53 [ERROR] Table .\test\d has no primary key in InnoDB data dictionary, but has one in MySQL!
Normally, the solution to copy
from Linux to Windows is to create the tables on Linux with the
lower_case_table_names option enabled.
Partitioned tables, with
#P# appended to the
filename, were not covered by that solution.
(Bug #11765438, Bug #58406)
Executing mysqlbinlog with the
N was equal either to 0
or to a value greater than the length of the dump file, caused
it to crash.
This issue was introduced in MySQL 5.5.18 by the fix for Bug #32228 and Bug #11747416. (Bug #13593869, Bug #64035)
On Windows replication slave hosts,
SLAVE took an excessive length of time to complete
when the master was down.
(Bug #11752315, Bug #43460)
The shared version of
libmysqlclient did not
export these functions for linking by client programs:
A query that used an index on a
CHAR column referenced in a
BETWEEN clause could return invalid results.
(Bug #13463488, Bug #63437)
Expressions that compared a
BIGINT column with any
non-integer constant were performed using integers rather than
decimal or float values, with the result that the constant could
be truncated. This could lead to any such comparison that used
BETWEEN yielding false positive or
(Bug #13463415, Bug #11758543, Bug #63502, Bug #50756)
When the optimizer performed conversion of
DECIMAL values while evaluating
range conditions, it could produce incorrect results.
When running mysqldump with both the
--flush-logs options, the
flushing of the log performed an implicit
Statements That Cause an Implicit Commit), causing more than one
transaction to be used and thus breaking consistency.
(Bug #12809202, Bug #61854)
It was possible on replication slaves where
FEDERATED tables were in use to get
timeouts on long-running operations, such as Error 1160
Got an error writing communication
FEDERATED tables did
not need to be replicated for the issue to occur.
(Bug #11758931, Bug #51196)
References: See also Bug #12896628, Bug #61790.
If an attempt to initiate a statement failed, the issue could not be reported to the client because it was not prepared to receive any error messages prior to the execution of any statement. Since the user could not execute any queries, they were simply disconnected without providing a clear error.
After the fix for this issue, the client is prepared for an error as soon as it attempts to initiate a statement, so that the error can be reported prior to disconnecting the user. (Bug #11755281, Bug #47032)
It was possible in the event of successive failures for mysqld_safe to restart quickly enough to consume excessive amounts of CPU. Now, on systems that support the sleep and date system utilities, mysqld_safe checks to see whether it has restarted more than 5 times in the current second, and if so, waits 1 second before attempting another restart. (Bug #11761530, Bug #54035)
The stored routine cache was subject to a small memory leak that over time or with many routines being used could result in out-of-memory errors.
The fix for this issue also introduces a new global server
stored_program_cache which can
be used for controlling the size of the stored routine cache.
(Bug #44585, Bug #11753187)
Using myisamchk with the sort recover method to repair a table having fixed-width row format could cause the row pointer size to be reduced, effectively resulting in a smaller maximum data file size. (Bug #48848, Bug #11756869)
Under some circumstances, the result of
depended on the contents of the previous row.
(Bug #42404, Bug #11751514)
libmysql.dll library was missing
(Bug #69204, Bug #16797982, Bug #62394)