Percona Server 5.6.26-74.0 发布，主要更新内容如下：
- TokuDB storage engine source has been merged into the Percona Servercode. TokuDB storage engine
tokudb_versionvariable now has the same value as thePercona Server
- TokuDB Hot Backup has been renamed to Percona TokuBackup and it is now open source.Source code has been integrated into Percona Server code as a git submodule. TokuDB Hot Backupplugin source code has been merged into Percona Server code.
- Tokutek Fractal Tree has been renamed to Percona FT and its source code has been integrated into Percona Server code as a git submodule.
- TokuDB tests for Percona Server 5.6 have been merged into Percona Server 5.6 code.
- Google SNAPPY compression/decompression algorithm is now available as TokuDB Compression table format.
- Percona Server now supports changing the
server_idvariable per session, by implementing the new
pseudo_server_idvariable. This feature is also fixing upstream bug#35125.
- Percona Server has temporarily disabled savepoints in triggers and stored functions. The reason is that even having fixed bug #1438990 and bug #1464468 we have found more cases where savepoints in triggers break binary logging and replication, resulting in server crashes and broken slaves. This feature will be disabled until the above issues are properly resolved.
LOCK TABLES FOR BACKUPnow flushes the current binary log coordinates to InnoDB. Thus, under active
LOCK TABLES FOR BACKUP, the binary log coordinates in InnoDB are consistent with its redo log and any non-transactional updates (as the latter are blocked by
LOCK TABLES FOR BACKUP). It is planned that this change will enable Percona XtraBackup to avoid issuing the more invasive
LOCK BINLOG FOR BACKUPcommand under some circumstances.
innodb_stresshas been added to the list of default MTR suites. For most supported systems satisfying the newly added dependencies is straightforward, but on CentOS 5, the default Python is too old. Thus
python26-mysqldbpackages should be installed there and
python26should be made the default python for the testsuite environment.
- Three new TokuDB variables,
tokudb_checkpoint_pool_threads, have been implemented to improve the controlling of thread pool size.
- Percona Server has implemented new
tokudb_enable_partial_evictionoption in TokuDBto allow disabling of partial eviction of nodes.
- Percona Server has implemented new
tokudb_compress_buffers_before_evictionoption inTokuDB which allows the evictor to compress unused internal node partitions in order to reduce memory requirements as a first step of partial eviction before fully evicting the partition and eventually the entire node.
GLOBAL_TEMPORARY_TABLEStable would crash threads working with internal temporary tables used by
ALTER TABLE. Bug fixed #1113388.
- Selecting from
GLOBAL_TEMPORARY_TABLEStable while running an online
ALTER TABLEon a partitioned table in parallel could lead to a server crash. Bug fixed #1193264.
- Kill Idle Transactions feature could cause an assertion on a debug build due to a race condition. Bug fixed #1206008.
libmylsqclient_16symbols were missing in Percona Server shared library package onRHEL/CentOS 7. Bug fixed #1420691.
- Prepared statements in stored procedures could crash Response Time Distribution plugin. Bug fixed #1426345.
- When variable
innodb_corrupt_table_actionis set to
Warn/Salvagethen server could crash on updating table statistics during query execution on affected tables. Bug fixed#1426610.
- A sequence of failing
TRUNCATE TABLE, then insert to that table, and
CHECK TABLEwould crash the server. Bug fixed #1433197.
- When InnoDB change buffering was enabled and used, executing a
FLUSH TABLE ... FOR EXPORTwould cause a server hang and
SHOW PROCESSLISTwould show that table in a
System Lockstate. Bug fixed #1454441 (upstream #77011).
RESET CHANGE_PAGE_BITMAPSpairs of commands were inadvertently joined, i.e. issuing either command had the effect of both. The first pair, besides flushing both index statistics and changed page bitmaps, had the effect of
RELOADprivilege. The second pair resulted in
FLUSH USER_STATISTICSdestroying changed page bitmaps. Bug fixed #1472251.
my.cnfwould result in server crashing on startup. The workaround is to enable
super_read_onlydynamically on a running server.Bug fixed #1389935 ( the fix was ported from Facebook patch #14d5d9).
super_read_onlyas a command line option would not enable
read_only. Bug fixed #1389935 ( the fix was ported from Facebook patch #14d5d9).
- If a new connection thread was created while a
SHOW PROCESSLISTcommand or a
INFORMATION_SCHEMA.PROCESSLISTquery was in progress, it could have a negative
TIME_MSvalue returned in the
PROCESSLISToutput. Bug fixed #1379582.
- With support for Fake Changes enabled, a write to an InnoDB table that would cause B-tree reorganization could lead to server assertion with the
unknown error code 1000. Bug fixed#1410410.
ALTER TABLE ... DISCARD TABLESPACEwith support for Fake Changes enabled would lead to a server assertion. Bug fixed #1372219.
ALTER TABLEdid not allow to change a column to
NOT NULLif the column was referenced in a foreign key. Bug fixed #1470677 (upstream #77591).
DROP TABLE IF EXISTSwhich fails due to a foreign key presence could break replication if slave had replication filters. Bug fixed #1475107 (upstream #77684).
- Enabling Log Archiving for XtraDB when
--innodb-read-onlyoption was enabled would cause server to crash. Bug fixed #1484432.
- LRU manager thread flushing was being accounted to
buffer_flush_backgroundInnoDBmetrics which was wrong and redundant. Bug fixed #1491420.
- Fixed a typo in the cleaner thread loop where
n_flushedis added to, instead of reset, by the idle server flushing. This may cause a cleaner thread sleep skip on a non-idle server. Bug fixed #1491435.
- Running TokuDB for a long time with lots of file open and close operations could lead to a server crash due to server incorrectly setting a reserved value. Bug fixed #690.
- Fixed TokuDB memory leak due to data race in context status initialization. Bug fixed #697.
- Removed unnecessary calls to
malloc_usable_size()function in PerconaFT library to improve the performance. Bug fixed #682.
Percona 为 mysql”>MySQL 数据库服务器进行了改进，在功能和性能上较 MySQL 有着很显著的提升。该版本提升了在高负载情况下的 InnoDB 的性能、为 DBA 提供一些非常有用的性能诊断工具；另外有更多的参数和命令来控制服务器行为。
Percona Server 只包含 MySQL 的服务器版，并没有提供相应对 MySQL 的 Connector 和 GUI 工具进行改进。