Changes in MySQL 5.7.7 (2015-04-08, Release Candidate)
Functionality Added or Changed
- Important Change; InnoDB: The following changes were made to
InnoDB
configuration option default values:- The
innodb_file_format
default value was changed toBarracuda
. The previous default value wasAntelope
. This change allows tables to use Compressed or Dynamic row formats. - The
innodb_large_prefix
default value was changed toON
. The previous default wasOFF
. Wheninnodb_file_format
is set toBarracuda
,innodb_large_prefix=ON
allows index key prefixes longer than 767 bytes (up to 3072 bytes) for tables that use a Compressed or Dynamic row format. - The
innodb_strict_mode
default value was changed toON
. The previous default wasOFF
. Wheninnodb_strict_mode
is enabled,InnoDB
raises error conditions in certain cases, rather than issuing a warning and processing the specified statement (perhaps with unintended behavior).
The configuration parameter default changes described above may affect replication and mysqldump operations. Consider the following recommendations when using the new default settings:
- When replicating or replaying mysqldump data from older MySQL versions to MySQL 5.7.7 or higher, consider setting
innodb_strict_mode
toOFF
to avoid errors. Target settings should not be more strict than source settings. - When replicating from MySQL 5.7.7 or higher to older slaves, consider setting
innodb_file_format=Barracuda
andinnodb_large_prefix=ON
on the slave so that the target and source have the same settings.
The following file format related configuration options are deprecated and will be removed in a future MySQL version:
These four configuration options were provided for creating tables compatible with earlier versions of
InnoDB
in MySQL 5.1. Now that MySQL 5.1 has reached the end of its product lifecycle, these options are no longer required. Also, the file format scheme, by which named file formats would be introduced as new features were added, was not used after introduction of theBarracuda
file format.InnoDB
formats have changed since the introduction of theBarracuda
file format, but new named file formats have not been added.If non-default values are used for any of the four deprecated options,
InnoDB
prints a deprecation and removal warning to the server error log. The same warning is issued to the client if the parameters are set dynamically using aSET
statement. - The
- Important Change; InnoDB: The
innodb_buffer_pool_dump_at_shutdown
andinnodb_buffer_pool_load_at_startup
configuration options are now enabled by default. With this change, a percentage of most-recently-used buffer pool pages is dumped at server shutdown and restored at server startup. This behavior helps avoid a lengthy buffer pool warmup period after restarting the server, particularly for instances with large buffer pools. Theinnodb_buffer_pool_dump_pct
option defines the percentage of buffer pool pages that are dumped. The default value forinnodb_buffer_pool_dump_pct
is reduced from 100 to 25.These configuration option default value changes represent a change in behaviour at server shutdown and startup. If you prefer the previous default values, it is recommended that you configure the options explicitly in your MySQL configuration file after upgrading to MySQL 5.7.7 or later, and before restarting the server.
For more information, see Saving and Restoring the Buffer Pool State.
- Important Change; InnoDB: The
innodb_checksum_algorithm
default value is nowcrc32
. The previous default setting wasinnodb
. This change also means thatinnodb_checksums=ON
is now equivalent toinnodb_checksum_algorithm=crc32
instead ofinnodb_checksum_algorithm=innodb
. - InnoDB: The
InnoDB
MeCab full-text parser plugin now supports theeucjpms
,cp932
, andutf8mb4
character sets. (Bug #20534096) - InnoDB: To address a scalability bottleneck for some workloads where
LOCK_grant
is locked in read-mode,LOCK_grant
locks are now partitioned. Read lock requests onLOCK_grant
now acquire one of multipleLOCK_grant
partitions. Write locks must acquire all partitions.To address another scalability bottleneck, the server no longer performs unnecessary lock acquisitions when creating interal temporary tables.
References: See also: Bug #72829, Bug #20023139.
- Replication: The defaults of some replication related variables have been modified. The following changes have been made:
binlog_gtid_simple_recovery=TRUE
binlog-format=ROW
binlog_error_action=ABORT_SERVER
sync_binlog=1
slave_net_timeout=60
Additionally, the session scope of
gtid_executed
has been deprecated. The global scope ofgtid_executed
remains supported. - Replication: The XA implementation in MySQL has been made much more compatible with the XA specification. A prepared XA transaction is no longer rolled back at disconnect. Now when replicating using the binary log, an XA transaction in
PREPARED
state persists in the binary log until an explicitXA COMMIT
orXA ROLLBACK
statement is issued. In prior versions, an XA transaction that was inPREPARED
state would be rolled back on clean server shutdown or client disconnect. Similarly, an XA transaction that was inPREPARED
state would still exist inPREPARED
state in case the server was shut down abnormally and then started again, but the contents of the transaction could not be written to the binary log. As part of this feature, a new event,XA_prepare_log_event
, has been added to track XA transactions in thePREPARED
state and enable them to be replicated. To finalize a two-phase XA transaction, theXA COMMIT
orXA ROLLBACK
is recorded separately in the binary log, possibly interleaving with other transactions. XA transactions committed with the newXA COMMIT ONE PHASE
syntax are logged as one part usingXA_prepare_log_event
.References: See also: Bug #12161, Bug #11745231, Bug #75204, Bug #20214365.
- Performance Schema stage event instruments that provide statement progress information now are enabled and timed by default. The affected instruments are those displayed by this statement:
SELECT * FROM performance_schema.setup_instruments WHERE ENABLED=‘YES‘ AND NAME LIKE "stage/%";
(Bug #20685859)
- The
XID
column of Performance Schema transaction tables (for example,events_transactions_current
) has been split into three columns to permit access to the component parts of XID values. The new columns areXID_FORMAT_ID
,XID_GTRID
, andXID_BQUAL
. (Bug #18320361) - In MySQL 5.7.6, the
NO_AUTO_CREATE_USER
was deprecated. (It is preferable to create MySQL accounts withCREATE USER
rather thanGRANT
.) Now the default SQL mode includesNO_AUTO_CREATE_USER
and assignments tosql_mode
that change theNO_AUTO_CREATE_USER
mode state produce a warning, except assignments that setsql_mode
toDEFAULT
.NO_AUTO_CREATE_USER
will be removed in a future MySQL version, at which point its effect will be enabled at all times (GRANT
will not create accounts). - Previously, view definitions were not permitted to contain derived tables (subqueries) in the
FROM
clause. This restriction has now been lifted.Previously, derived tables (subqueries) or views in the
FROM
clause could not be merged into the outer query if they contained subqueries in theSELECT
list. Instead, they were processed using materialization. This restriction has now been lifted so that queries previously executed using materialization can be executed more quickly using merging. (Bug #12755, Bug #11745276, Bug #60417, Bug #11865600)
原文地址:https://www.cnblogs.com/jinzhenshui/p/12584208.html