MySQL 5.6 Release Notes
A known limitation of this release:
If you have InnoDB
tables with full-text
search indexes and you are upgrading from MySQL 5.6.10 to a
MySQL version up to and including MySQL 5.6.18, the server
will fail to start after the upgrade (Bug#72079). This bug is
fixed in MySQL 5.6.19. As a workaround, remove full-text
search indexes prior to upgrading and rebuild full-text search
indexes after the upgrade is completed.
Previously, MySQL Server distributions included the MySQL Reference Manual in Info format (the Docs/mysql.info file). Because the license for the manual restricts redistribution, its inclusion in Community packages caused problems for downstream redistributors, such as those who create Linux distributions. Community distributions of MySQL Server no longer include the mysql.info file, to make the repackaging and redistribution process easier (for example, the source tarball and its checksum can be used directly). This change applies to all source and binary Community packaging formats. Commercial (Enterprise) distributions are unchanged.
For those who wish to continue using the MySQL Reference Manual in Info format, we have made it available at https://dev.mysql.com/doc/.
Incompatible Change:
Several statement instruments in the
setup_instruments
table are used by
the Performance Schema during the early stages of statement
classification before the exact statement type is known. These
instruments were renamed to more clearly reflect their
“abstract” nature:
Old Instrument Name | New Instrument Name |
---|---|
statement/com/ |
statement/abstract/new_packet |
statement/com/Query |
statement/abstract/Query |
statement/rpl/relay_log |
statement/abstract/relay_log |
In addition, statistics for abstract instruments are no longer collected in the following tables, because no such instrument is ever used as the final classification for a statement:
events_statements_summary_by_thread_by_event_name events_statements_summary_by_account_by_event_name events_statements_summary_by_user_by_event_name events_statements_summary_by_host_by_event_name events_statements_summary_global_by_event_name
Applications that refer to the old instrument names must be updated with the new names. For more information about the use of abstract instruments in statement classification, see Performance Schema Statement Event Tables. (Bug #16750433, Bug #17271055)
The Performance Schema now instruments the read/write lock
Delegate::lock
, which is used for the
following classes:
Trans_delegate Binlog_storage_delegate Binlog_transmit_delegate Binlog_relay_IO_delegate
A different instrument name is used for each subclass, to have
distinct statistics for distinct uses. The instruments are
visible in the schema.setup_instruments
table
and have these names:
wait/synch/rwlock/sql/Trans_delegate::lock wait/synch/rwlock/sql/Binlog_storage_delegate::lock wait/synch/rwlock/sql/Binlog_transmit_delegate::lock wait/synch/rwlock/sql/Binlog_relay_IO_delegate::lock
(Bug #17590161, Bug #70577)
A new CMake option,
WITH_ASAN
, permits enabling
AddressSanitizer for compilers that support it.
(Bug #17435338)
The hash function used for metadata locking was modified to reduce overhead. (Bug #68487, Bug #16396598)
InnoDB; Replication:
The InnoDB
mecached plugin
would update a record before inserting to the binary log, which
would cause slave server replication to stop. The insert should
occur before the update.
(Bug #17358875)
InnoDB: A regression introduced by the fix for Bug#17371537 resulted a memory leak for memcached insert operations. (Bug #17738935)
References: See also: Bug #17371537.
InnoDB:
Fault-tolerant code found in the log apply code for
InnoDB
ALTER TABLE ... IN
PLACE
could result in data corruption.
(Bug #17625063, Bug #17512497)
InnoDB:
The trx->error_key_num
field was not
initialized in the error injection code found in
storage/innobase/handler/handler0alter.cc
.
The error_key_num
field is usually 0 but can
be a non zero value if the memory buffer of a DDL transaction
object is reused.
(Bug #17624926)
InnoDB: Databases names beginning with a digit would cause a full-text search (FTS) parser error. (Bug #17607956)
References: See also: Bug #17161372.
InnoDB:
An ALTER TABLE ...
CHANGE [COLUMN]
operation would result in an
rbt_empty(index_cache->words)
assertion.
(Bug #17536995)
InnoDB:
CHECK TABLE
would ignore the
QUICK
option.
(Bug #17513737)
InnoDB:
An excessive amount of memory would be consumed when querying
INFORMATION_SCHEMA.INNODB_FT_INDEX_TABLE
.
The problem would occur for very large full-text search indexes.
(Bug #17483582, Bug #70329)
InnoDB:
Running SHOW ENGINE
INNODB STATUS
on one connection thread and killing
that thread by running a
KILL CONNECTION
statement from a different connection thread would result in a
severe error.
(Bug #17474166)
InnoDB:
In debug builds, test case failures would occur due to
ibuf_contract_ext
performing merges and
dict_stats_update
returning evicted pages
back into the buffer pool while
ibuf_change_buffering_debug
is enabled.
(Bug #17446090)
InnoDB:
Setting the O_DIRECT
flag on a file on
tmpfs
on some operating systems would result
in an error printed to the error log. Creating multiple
temporary tables on tmpfs
would cause the
error to be printed repeatedly. The error message has been
changed to a warning that is only printed once when running
CREATE TABLE
multiple times.
(Bug #17441867)
InnoDB:
InnoDB
failed to return an error when
attempting to run a query after discarding the tablespace.
(Bug #17431533)
InnoDB: A severe error would occur after discarding a tablespace. (Bug #17430207)
InnoDB:
The
information_schema.innodb_metrics
index_merge
counter was not incremented in
btr0btr.cc
. This patch also introduces new
counters (index_page_reorg_attempts
,
index_page_reorg_successful
and
index_page_discards
) and renames the
index_merges
counter to
index_page_merge_attempts
to distinguish it
from the index_page_merge_successful
counter.
(Bug #17409657, Bug #70241)
InnoDB:
During a TRUNCATE TABLE
operation, InnoDB: Trying to TRUNCATE a missing index
of table ... warnings would be printed to the error
log. These warnings should not be printed when the index is a
full-text search (FTS) index.
(Bug #17402002, Bug #70226)
References: See also: Bug #12429565.
InnoDB: During parallel full-text search (FTS) index creation, a scanner thread reads in documents and passes them to the tokenizer. The tokenizer frees documents from memory when tokenization is complete. When tokenizing documents with a large amount of text, the tokenizer thread would not keep pace with the scanner thread. As a result, memory would not be freed fast enough and the “tokenization pending list” would grow in size. (Bug #17384979)
InnoDB:
trx_create
and trx_free
would be called for every memcached
get
request.
(Bug #17371537, Bug #70172)
InnoDB:
A full-text search (FTS) BOOLEAN MODE
query
with an invalid character in the query string could result in a
memory access violation failure.
(Bug #17350055)
InnoDB: Full-text index creation on a large table failed due to insufficient temporary table space and result in a misleading “incorrect key file” error. (Bug #17339606)
InnoDB:
In btr_validate_level
there are checks to
ensure that all B-tree pages are marked when allocated. The
checks failed on the change buffer because the allocation of
change buffer pages is handled differently than other B-tree
pages.
(Bug #16884217)
InnoDB:
The hardcoded size for the srv_max_n_threads
variable was insufficient. The variable setting is now
configured based on the maximum number of connection threads and
InnoDB
background threads.
(Bug #16884077)
InnoDB:
A SELECT COUNT(*)
query would take a long
time to complete when run concurrently with a
LOAD DATA
operation. The
mtr_memo_contains
function, which determines
if an object is part of a memo in a mini transaction, contained
a nested loop that caused the query to run slowly.
(Bug #16764240, Bug #69141)
InnoDB:
When the change buffer is enabled, InnoDB
failed to write a transaction log record when merging a record
from the insert buffer to a secondary index page if the insert
was performed as an “update-in-place”.
(Bug #16752251, Bug #69122)
InnoDB:
An existing full-text index would become invalid after running
ALTER TABLE ADD
FULLTEXT
due to an unsynchronized full-text cache.
(Bug #16662990, Bug #17373659)
InnoDB:
Due to a regression in MySQL 5.6, creating or dropping tables
with innodb_force_recovery
set
to 3
(SRV_FORCE_NO_TRX_UNDO
) failed. Additionally,
this bug fix includes a code modification that sets
InnoDB
to read-only when
innodb_force_recovery
is set to
a value greater than 3
(SRV_FORCE_NO_TRX_UNDO
).
(Bug #16631778, Bug #69892)
InnoDB:
An InnoDB
memcached
configuration error message contained an incorrect file name.
The error message stated, Please create config table
containers in database innodb_memcache by running
innodb_config.sql. error 31. The correct file name
is innodb_memcached_config.sql
. Also, the
“error 31” portion of the error message has been
translated to its text equivalent, which is “Table not
found”.
(Bug #16498810, Bug #68684)
InnoDB:
In mutex_spin_wait()
, the
sync_array_reserve_cell
function could fail
to find an empty slot on systems with sync wait arrays that are
small in size, resulting in an error.
(Bug #16245498)
InnoDB: Full-text search (FTS) index savepoint information would not be set resulting in a severe error when attempting to rollback to the savepoint. (Bug #14639605, Bug #17456092)
InnoDB:
When index_read_map
is called for an exact
search and fails to return a record due to non-matching search
criteria, the cursor would be positioned on the next record
after the searched key. A subsequent call to index_next
would return the next record instead of returning the
previous non-matching row, thereby skipping a record.
(Bug #14621190, Bug #15965874, Bug #17314241, Bug #70038, Bug #17413093, Bug #12860669, Bug #60220, Bug #17565888)
InnoDB:
An implicit rollback caused the server to halt when restarting
with an innodb_force_recovery
value of 3 or greater. This bug was addressed by the combination
of fixes for Bug #16310467 and Bug #17253499.
(Bug #14178835)
References: See also: Bug #16310467, Bug #17253499.
InnoDB:
Converting a table with a large number of columns from
MyISAM
to
InnoDB
would cause an assertion due
to insufficient log buffer space. Instead of asserting,
InnoDB
now attempts to increase log buffer
size automatically if the redo log size is too large.
(Bug #11758196, Bug #50366)
Partitioning:
The storage engine was set incorrectly during a rebuild of a
partition; the table storage engine was ignored and the default
storage engine used instead. Thus, in MySQL 5.1, it was possible
for REBUILD PARTITION
to change the partition
storage engine from InnoDB
to
MyISAM
, and for the reverse
(rebuilding partitions of MyISAM
tables
causing the partitions to use InnoDB
) to
occurin MySQL 5.5 and later. Now, when rebuilding partitions,
the storage engine actually used by the table is checked and
used by the handler for the rebuild operation, so that the
partition storage engine is not inadvertently changed.
(Bug #17559867)
Partitioning:
After disabling the parent table's indexes with
ALTER TABLE ...
DISABLE KEYS
, rebuilding any of its partitions enabled
the indexes on those partitions, leading
MyISAM
to fail with an error when
the optimizer tried to use one of the affected indexes.
Now in such cases, we check for disabled indexes on the table before rebuilding any of its partitions. If the indexes have been disabled, then we disable them on the partition following the rebuild. (Bug #16051817)
Replication: A replication master did not handle correctly the disabling of the semisync plugin on the master and the slave, with a subsequent stopping of the slave. (Bug #17460821, Bug #70349)
Replication:
The final argument in the SET
clause of a
LOAD DATA ...
SET
statement was repeated in the binary log.
(Bug #17429677, Bug #70277)
Replication: When an error encountered by the dump thread while reading events from the active binary log file was a temporary error, so that the dump thread tried to read the event, it was possible for the dump thread to seek the wrong position, which could cause one or more events to be resent. To prevent this, the thread's position is obtained after each correct read of an event.
In addition, with this fix, only binary logs that are not closed normally are marked as possibly being corrupted.
Finally, two warnings are added; these are now returned when a dump thread encounters a temporary error. (Bug #17402313)
Replication:
Setting
rpl_semi_sync_master_enabled
while the master was waiting for a reply from the slave could in
some cases cause the master to fail.
(Bug #17327454, Bug #70045)
Replication:
When stopping the I/O thread, it was possible with a very large
transaction (equivalent to a binary log size greater than 100MB)
that the thread did not receive the transaction to the end. When
reconnecting with MASTER_AUTO_POSITION=1
it
then tried to fetch changes from the next transaction, which
could lead to loss of the incomplete transaction and its data.
(Bug #17280176, Bug #69943)
Replication:
Trying to set
CHANGE MASTER
TO ... MASTER_AUTO_POSITION = 0
failed with error 1777
(ER_AUTO_POSITION_REQUIRES_GTID_MODE_ON).
(Bug #17277744)
Replication:
The value of LAST_INSERT_ID()
was
not correctly replicated when filtering rules were used on the
slave.
(Bug #17234370, Bug #69861)
Replication: An internal function used for storing GTID values could sometimes try to handle them as strings of the wrong length. (Bug #17032712, Bug #69618)
Replication:
During row-based replication with
binlog_row_image
set to
MINIMAL
, updating only some columns of a
table having 9 or more columns caused
mysqlbinlog to fail when it was used with the
--verbose
option.
(Bug #16960133)
Replication:
Issuing a GRANT
statement with
invalid parameters caused the master to write
LOST_EVENTS
events into its binary logs,
causing replication to stop. Now such cases, if one or more
grants or revocations of privileges are successful, an incident
is written to the log; otherwise, only a warning is logged.
(Bug #16629195, Bug #68892)
libmysqlclient
version 18 files were removed
from MySQL-shared-compat
RPM packages to
avoid a conflict between the MySQL-shared
and
MySQL-shared-compat
RPM packages.
(Bug #17749617)
Enabling Index Merge optimizer switches and setting a small
sort_buffer_size
value could
lead to a server exit.
(Bug #17617945)
Some license and documentation files were missing from Windows MSI packages. (Bug #17584523)
Semijoin materialization strategy was not used for
VARCHAR
columns longer than 512 bytes,
resulting in use of a less-efficient strategy and worse query
performance. (The limit in characters rather than bytes depends
on the column character set; 170 characters for
utf8
, for example.)
(Bug #17566396)
Using MySQL Installer to install MySQL on Windows, then using Uninstall a Program in the Control Panel to uninstall MySQL, resulted in the MySQL service entry not being removed. (Bug #17550741)
Selecting from the
session_connect_attrs
Performance
Schema table under high load could cause a server exit.
(Bug #17542370)
Compilation failures under Visual Studio 2012 were corrected. (Bug #17430236)
An assertion was raised if SET PASSWORD
was
used for an account that has been manually deleted from the
mysql.user
table but still present in memory.
(Bug #17359329)
The CLIENT_CONNECT_WITH_DB
flag was
improperly handled in the C client library. This could lead to a
malformed packet sent to the server.
(Bug #17351732)
The filesort
implementation sometimes failed
to allocate enough buffer space, leading to a server exit.
(Bug #17326567)
The mysql_options()
C API
function could leak memory if called more than once with the
MYSQL_SET_CLIENT_IP
option.
(Bug #17297012)
The CONV()
function could call
abs(INT_MIN)
, which is undefined, and cause a
server exit.
(Bug #17296644)
An error array in the SSL code was missing a comma, leading to implicit concatenation of adjacent messages and a resulting off-by-one error in the relationship between error numbers and messages. (Bug #17294150)
GRANT
without an
IDENTIFIED BY
clause resulted in an error
even for existing users.
(Bug #16938568)
GROUP_CONCAT()
with an invalid
separator could cause a server exit.
(Bug #16870783)
An internal InnoDB
string routine could write
past the end of a buffer.
(Bug #16765410)
For uninstall operations, the MySQL Server MSI installer failed to remove some files if the server was running. This could lead to problems for a subsequent installation of a lower MySQL version: The installer reported a successful operation but not some of the files from the original installation were not replaced by their lower-versioned counterparts. (Bug #16685125)
GIS intersection-related code was missing a return value check, leading to a loop in nondebug builds and a raised assertion in debug builds. (Bug #16659166)
Using the binary client/server protocol, the second execution of
a prepared statement for a query with parameters in the
LIMIT
clause raised an assertion.
(Bug #16346241)
For upgrades using the Windows MSI package installer, the upgrade dialog message was missing the “from” version. (Bug #16053094)
Very long database names in queries could cause the server to exit. (Bug #15912213, Bug #16900358)
Standalone Windows MSI packages did not have the
ALLUSERS
property set. They now set
ALLUSERS=1
. For earlier MSI packages in this
MySQL series, a workaround is to use the following command:
C:\> msiexec /i msi_installer_name
ALLUSERS=1
(Bug #14647206)
Recursion by functions called as arguments to XPath expressions was not handled correctly, sometimes causing such expressions to fail. (Bug #14040071)
Some .pdb
files were missing from Windows
Zip archive distributions.
(Bug #13878021)
Several issues identified by the Coverity static analysis tool were fixed. Thanks to Jan Staněk and Honza Horak for the patches. (Bug #70591, Bug #17590095)
Setting host_cache_size
at
startup had no effect.
(Bug #70552, Bug #17576516)
MySQL did not compile on OS X 10.9 (Mavericks). (Bug #70542, Bug #17647863)
In some cases, range conditions over indexes defined on column
prefixes returned incomplete result sets. (For example,
SELECT ... WHERE 'abcdef1' <
,
where the index on col_name
AND
col_name
< 'abcdef9'col_name
indexed
only the first 6 characters.)
(Bug #70341, Bug #17458273)
InnoDB
full-text searches failed to find
records within transactions that included savepoints.
(Bug #70333, Bug #17458835)
If asked to upgrade a server that was running without
InnoDB
enabled,
mysql_upgrade issued complaints about
InnoDB
tables not existing (tables that will
not exist unless InnoDB
is available).
(Bug #70152, Bug #17361912)
With the thread pool plugin enabled, the
PROCESSLIST_USER
and
PROCESSLIST_HOST
columns of the
threads
Performance Schema table
were always NULL
for client sessions. Also,
for the main thread, those columns were not
NULL
but set to a user account.
As part of the bug fix implementation, Performance Schema
instrumentation for the thread pool plugin was changed to use
thread_pool
, not sql
.
(Bug #70028, Bug #17310065, Bug #17049691)
Performance Schema instrumentation overhead was reduced for frequent connect/disconnect operations. (Bug #70018, Bug #17310878)
COUNT(DISTINCT)
should not count
NULL
values, but they were counted when the
optimizer used Loose Index Scan.
(Bug #69841, Bug #17222452)
In debug builds, static initialization code could call DBUG functions before the DBUG subsystem was initialized. (Bug #69653, Bug #17063675)
Some INSERT INTO ... SELECT ... FROM
statements were slow unless the
tmp_table_size
and
max_heap_table_size
system
variables were set large enough to permit the temporary table
used for query processing to be stored in the
MEMORY
storage engine.
(Bug #69368, Bug #16894092)
Some possible cases of memory use after being freed were fixed. Thanks to Jan Staněk for the patch. (Bug #68918, Bug #16725945)
Missing va_end()
calls were added to logging
and UCS2 code. Thanks to Jan Staněk for the patch.
(Bug #68896, Bug #16725769)
For queries of the form UPDATE ... WHERE
, incorrect rows could be updated. Unique keys
permit multiple unique_key
ORDER BY ... LIMIT
...NULL
values, but the
optimizer did not always consider all of them.
(Bug #68656, Bug #16482467)
For an ALTER TABLE
statement that
renamed or changed the default value of a
BINARY
column, the alteration was
done using a table copy and not in place.
(Bug #67141, Bug #14735373, Bug #69580, Bug #17024290)
The server uses the ethernet hardware address for UUID generation, but made assumptions about the names of ethernet devices rather than querying the system for their names. Thanks to Honza Horak for the patch. (Bug #63055, Bug #13548252)
Host names in grant tables are stored in lowercase, but
mysql_install_db could fail to observe this
convention, leading to accounts that could not be dropped with
DROP USER
.
(Bug #62255, Bug #12917164, Bug #62254, Bug #12917151)
Killing a query that is performing a filesort
operation resulted in an
ER_SERVER_SHUTDOWN
(Server
shutdown in progess) error.
(Bug #18256, Bug #11745656)