发布于 2017-05-23 08:59:20 | 141 次阅读 | 评论: 0 | 来源: 网友投递
MariaDB数据库
MariaDB基于事务的Maria存储引擎，替换了MySQL的MyISAM存储引擎，它使用了Percona的 XtraDB，InnoDB的变体，分支的开发者希望提供访问即将到来的MySQL 5.4 InnoDB性能。这个版本还包括了 PrimeBase XT (PBXT) 和 FederatedX存储引擎。
MariaDB 10.2 首个 GA 10.2.6 发布了。新版采用 InnoDB 为默认存储引擎，更多更新如下：
InnoDB is now the default storage engine. Until MariaDB 10.1, MariaDB used the XtraDB storage engine as default
Window functions have been introduced.
The SHOW CREATE USER statement was introduced
New CREATE USER options for limiting resource usage and tls/ssl
New ALTER USER statement
Recursive Common Table Expressions (MDEV-9864)
New WITH statement.WITHis a common table expression that allows you to refer to a subquery expression many times in a query (MDEV-8308 & MDEV-9864) — Original code from Galina Shalygina
Support for CHECK CONSTRAINT (MDEV-7563)
Support for DEFAULT with expressions (MDEV-10134)
BLOB and TEXT fields can now have aDEFAULTvalue
Lots of restrictions lifted for Virtual computed columns
Number of supported decimals in DECIMAL has increased from30to38(MDEV-10138)
Added catchall for list partitions (MDEV-8348)
Oracle-style EXECUTE IMMEDIATE statement (MDEV-10585)
PREPARE Statement now understands most expressions (MDEV-10866)
InnoDB tables now support spatial indexes
Better InnoDB crash recovery progress reporting (MDEV-11027)
Improvements to InnoDB startup/shutdown to make it more robust
AWS Key Management plugin added for Windows, CentOS, RHEL, and Fedora packages
The FOLLOWS/PRECEDES clauses have been added to the CREATE TRIGGER statement
Multiple triggers are now counted in the Executed_triggers status variable (MDEV-10915)
SHOW TRIGGERS and SHOW CREATE TRIGGER now include the date and time the trigger was created
DML_only flashback can rollback instances/databases/tables to an old snapshot (MDEV-10570)
New variable read_binlog_speed_limit permits restricting the speed at which the slave reads the binlog from the master (MDEV-11064) — Original code from Tencent Game DBA Team, developed by chouryzhou.
Delayed replication is supported (MDEV-7145)
Compression of events in the binary log is supported (MDEV-11065) — Original code from Tencent Game DBA Team, developed by vinchen.
Default binary log format changed to mixed (MDEV-7635)
Default value of replicate_annotate_row_events changed toON(MDEV-7635)
Default value of slave_net_timeout reduced to 60 seconds (MDEV-7635)
Default server_id changed from0to1
JSON functions added (MDEV-9143)
Implement ST_AsGeoJSON and ST_GeomFromGeoJSON functions so the spatial features can be imported/exported using GeoJSON format (MDEV-11042)
An information schema plugin to report all user variables, which creates the Information Schema USER_VARIABLES Table (MDEV-7331)
EXPLAIN FORMAT=JSON now showsouter_ref_conditionfield which contains the condition that the(?) SELECT checks on each re-execution (MDEV-9652)
EXPLAN FORMAT=JSON now showssort_keyfield which shows the sort criteria used byfilesortoperation. (commit 2078392)
EXPLAIN used to show incorrect information about how the optimizer resolvedORDER BYclause orDistinct. This was a long-standing problem with roots back in MySQL. Now, after MDEV-8646 and related fixes, the problem doesn't exist anymore. (For test cases, see MDEV-7982, MDEV-8857, MDEV-7885, MDEV-326)
Connection setup was made faster by moving creation of THD to new thread (MDEV-6150)
Pushdown conditions into non-mergeable views/derived tables (MDEV-9197) — Original code from Galina Shalygina
ANALYZE TABLE has been re-implemented so as not to lock the entire table when collecting engine independent statistics (MDEV-7901)
Internal CRC32 routines use the optimized implementation on Power8 — MDEV-9872
Table cache can automatically partition itself as needed to reduce the contention (MDEV-10296)
NO PAD collations, which means that end space are significant in comparisons (MDEV-9711) — Original code from Daniil Medvedev
MariaDB now works when started with a MySQL 5.7.6+ data directory (MDEV-11170)
Zipped File Tables for the CONNECT storage engine (MDEV-11295)
The CONNECT engine now supports the JDBC Table type (MDEV-9765)
For a list of all new variables, see System Variables Added in MariaDB 10.2 and Status Variables Added in MariaDB 10.2. These include:
aria_recover has been renamed to aria_recover_options (MDEV-8542)
Default values of the aria_recover and myisam_recover_options system variables changed toBACKUP,QUICK
The server version can now be faked to work around dated applications that require a particular version string (MDEV-7780
slave_parallel_workers is now an alias for slave_parallel_threads
New status variables com_alter_user, com_multi and com_show_create_user
New variable for setting a directory for storing temporary non-tablespace InnoDB files, innodb_tmpdir
New variable read_binlog_speed_limit permits restricting the speed at which the slave reads the binlog from the master (MDEV-11064)
innodb_log_files_in_group can now be set to1(MDEV-12061)
The thread pool now gives higher priority to connections that have an active transaction. This can be controlled with the new thread_pool_prio_kickup_timer and thread_pool_priority system variables. (MDEV-10297)
Default value of group_concat_max_len changed to 1M (MDEV-7635)
Default value of innodb_compression_algorithm changed tozlib- this does not mean pages are now compressed by default, see compression (MDEV-11838)
Default value of innodb_log_compressed_pages changed toON(MDEV-7635)
Default value of innodb_use_atomic_writes and innodb_use_trim changed toON
The unused innodb_api_* variables have been removed (MDEV-12050)
Continuous binary log backup has been added to mysqlbinlog (MDEV-8713)
mysql_zap and mysqlbug have been removed (MDEV-7376, MDEV-8654)
Added support for OpenSSL 1.1 and LibreSSL (MDEV-10332)
Persistent AUTO_INCREMENT for InnoDB (MDEV-6076)
Support COM_RESET_CONNECTION (MDEV-10340)
"fast mutexes" have been removed. These aren't faster than normal mutexes, and have been disabled by default for years (MDEV-8111)
Old GPL client library is gone; now MariaDB Server comes with the LGPL Connector/C client library (MDEV-9055)