Functionality Added or Changed
InnoDB now permits concurrent reads
on a table while creating nonprimary unique indexes. (This was
found to create problems and was reverted in 5.5.12.)
Previously, Performance Schema instrumentation for both the binary log and the relay log used these instruments:
wait/io/file/sql/binlog wait/io/file/sql/binlog_index wait/synch/mutex/sql/MYSQL_BIN_LOG::LOCK_index wait/synch/cond/sql/MYSQL_BIN_LOG::update_cond
Now instrumentation for the relay log uses these instruments, which makes it possible to distinguish binary log and relay log events:
wait/io/file/sql/relaylog wait/io/file/sql/relaylog_index wait/synch/mutex/sql/MYSQL_RELAY_LOG::LOCK_index wait/synch/cond/sql/MYSQL_RELAY_LOG::update_cond
(Bug #59658, Bug #11766528)
MySQL distributions now include an
file that contains information about the source distribution,
such as the MySQL version from which it was created. MySQL
binary distributions additionally include an
INFO_BIN file that contains information
about how the distribution was built, such as compiler options
and feature flags. In RPM packages, these files are located in
tar.gz and derived packages,
they are located in the
under the location where the distribution is unpacked.
(Bug #42969, Bug #11751935)
Previously, for queries that were aborted due to a sort problem
or terminated with
KILL in the middle of a
sort, the server wrote the message
aborted to the error log. Now the server writes more
information about the cause of the error. These causes include:
Insufficient disk space in the temporary file directory prevented a temp file from being created
Insufficient memory for
sort_buffer_size to be
in the middle of a
The server was shut down while some queries were sorting
A transaction was rolled back or aborted due to a lock wait timeout or deadlock
Unexpected errors, such as a source table or even temp table was corrupt
Processing of a subquery failed which was also sorting
(Bug #30771, Bug #11747102)
SHOW NEW MASTER statement
has been removed.
For the Windows installer, debug information files and the embedded MySQL server have been removed from the standard MSI distribution file to reduce the download size for the majority of users.
If these files are needed, the Zip distribution must be
downloaded separately and be extracted in the installation
directory, which is most probably
Files\MySQL\MySQL Server 5.5 on English systems.
Please note that upon product de-installation, these extracted files from the Zip distribution must be removed from the system manually.
A new system variable,
controls the maximum size of parameter values that can be sent
API function. If not set at server startup, the default is the
value of the
system variable. This variable is deprecated. In MySQL 5.6, it
is removed and the maximum parameter size is controlled by
The length of the
plugin column of the
mysql.user system table is increased to 64
characters. This is now the same size as the
name column of the
(Bug #11766610, Bug #59752)
A problem with a previous fix for poor performance of
INSERT ON DUPLICATE KEY
UPDATE statements on tables having many partitions
caused the handler function for reading a row from a specific
index to fail to store the ID of the partition last used. This
caused some statements to fail with Can't find
(Bug #59297, Bug #11766232)
References: This bug is a regression of Bug #52455.
DROP DATABASE statement
could break statement-based replication.
(Bug #58381, Bug #11765416)
Two unused test files in
storage/ndb/test/sql contained incorrect
versions of the GNU Lesser General Public License. The files and
the directory containing them have been removed.
References: See also Bug #11810156.
Division of large numbers could cause stack corruption. (Bug #11792200)
Queries that used
cp1251 strings could result in an
“illegal mix of collations” error.
(Bug #60101, Bug #11766874)
mysql_load_plugin() C API
function did not clear the previous error.
(Bug #60075, Bug #11766854)
An assertion was raised if an
XA COMMIT was
issued when an XA transaction had already encountered an error
(such as a deadlock) that required the transaction to be rolled
(Bug #59986, Bug #11766788)
On some systems, debug builds of
could fail due to an uninitialized variable.
(Bug #59906, Bug #11766729)
The server read one byte too many when trying to process an XML
string lacking a closing single quote (
double quote (
") character used as an
(Bug #59901, Bug #11766725)
References: See also Bug #44332, Bug #11752979.
Attempting to create a spatial index on a
CHAR column longer than 31 bytes
led to an assertion failure if the server was compiled with
(Bug #59888, Bug #11766714)
Aggregation followed by a subquery could produce an incorrect result. (Bug #59839, Bug #11766675)
An incorrect character set pointer passed to
my_strtoll10_mb2() caused an assertion to be
(Bug #59648, Bug #11766519)
FIND_IN_SET() could work
differently in MySQL 5.5 than in 5.1.
(Bug #59405, Bug #11766317)
mysqldump did not quote database names in
ALTER DATABASE statements in its
output, which could cause an error at reload time for database
names containing a dash.
(Bug #59398, Bug #11766310)
MYSQL_HOME environment variable was being
(Bug #59280, Bug #11766219)
An invalid pathname argument for the
--defaults-extra-file option of
MySQL programs caused a program crash.
(Bug #59234, Bug #11766184)
On Windows, the
recently added to the
mysql.user table caused
the Configuration Wizard to fail.
(Bug #59038, Bug #11766011)
CREATE TRIGGER and
DROP TRIGGER can change the
prelocking list of stored routines, but the routine cache did
not detect such changes, resulting in routine execution with an
inaccurate locking list.
(Bug #58674, Bug #11765684)
The code for
PROCEDURE ANALYSE() had a
DBUG_RETURN statement, which could
cause a server crash in debug builds.
(Bug #58140, Bug #11765202)
An assertion was raised if a statement tried to upgrade a
metadata lock while there was an active
statement. Now if a statement tries to upgrade a metadata lock
in this situation, the server returns an
tbl_list WITH READ LOCK
error to the client.
(Bug #57649, Bug #11764779)
If a multiple-table update updated a row through two aliases and the first update physically moved the row, the second update failed to locate the row. This resulted in different errors depending on the storage engine, although these errors did not accurately describe the problem:
MyISAM, which is
nontransactional, the update executed first was performed but
the second was not. In addition, for two equal multiple-table
update statements, one could succeed and the other fail
depending on whether the record actually moved, which is
Now such an update returns an error if it will update a table through multiple aliases, and perform an update that may physically move the row in at least one of these aliases. (Bug #57373, Bug #11764529, Bug #55385, Bug #11762751)
In some cases,
returned an empty result when the previous statement failed.
(Bug #55847, Bug #11763166)
On Windows, an object in thread local storage could be used before the object was created. (Bug #55730, Bug #11763065)
For a client connected using SSL, the
variable was empty and did not show the possible cipher types.
(Bug #52596, Bug #11760210)
When used to upgrade tables, mysqlcheck (and
mysql_upgrade, which invokes
mysqlcheck) did not upgrade some tables for
which table repair was found to be necessary. In particular, it
failed to upgrade
that needed repair, leaving them in a nonupgraded state. This
mysqlcheck --check-upgrade ---auto-repair
checks for tables that are incompatible with the current
version of MySQL. It does this by issuing the
CHECK TABLE ...
FOR UPGRADE statement and examining the result.
For any table found to be incompatible,
mysqlcheck issues a
REPAIR TABLE statement. But
this fails for storage engines such as
InnoDB that do not support the
repair operation. Consequently, the table remained
To fix the problem, the following changes were made to
CHECK TABLE ... FOR
UPGRADE and mysqlcheck. Because
mysqlcheck, these changes also fix the
problem for mysql_upgrade.
ER_TABLE_NEEDS_UPGRADETable upgrade required. Please do "REPAIR TABLE `
tbl_name`" or dump/reload to fix it!
ER_TABLE_NEEDS_REBUILDTable rebuild required. Please do "ALTER TABLE `
tbl_name` FORCE" or dump/reload to fix it!
mysqlcheck recognizes the new error and
TABLE ... FORCE statement. The
FORCE option for
ALTER TABLE was recognized
but did nothing; now it is implemented and acts as a
“null” alter operation that rebuilds the table.
(Bug #47205, Bug #11755431)
CASE ... WHEN arguments had different
character sets, 8-bit values could be referenced as
raising an assertion.
(Bug #44793, Bug #11753363)
Bitmap functions used in one thread could change bitmaps used by other threads, raising an assertion. (Bug #43152, Bug #11752069)