Percona Server 5.5.16-22.0¶
Based on MySQL 5.5.16, including all the bug fixes in it, Percona Server 5.5.16-22.0 is now the current stable release in the 5.5 series. All of Percona ‘s software is open-source and free, all the details of the release can be found in the 5.5.16-22.0 milestone at Launchpad.
InnoDB Fake Changes¶
When restarting a slave server in a replication environment, the process can be speed up by having prefetch threads to warm the server: replay statements and then rollback at commit.
That makes prefetch simple but has high overhead from locking rows only to undo changes at rollback.
Using this approach, support for Fake Changes have been implemented in order to remove the overhead and make it faster.
By reading the rows for “INSERT”, “UPDATE” and “DELETE” statements but not updating them (Fake Changes), the rollback is very fast as in most cases there is nothing to do.
Kill Idle Transactions¶
NOTE: Percona classes this feature as Beta and possibly not yet suited for production environments.
This feature limits the age of idle XtraDB transactions. If a transaction is idle for more seconds than the threshold specified, it will be killed. This prevents users from blocking purge by mistake.
Block Startup until LRU dump is loaded¶
Added a new boolean option,
innodb_blocking_buffer_pool_restore, which is
OFF by default. When set to
ON, restoring from the LRU dump file is synchronous, i.e. XtraDB waits until it is complete before reporting successful startup to the server. Bug Fixed: #785489 (Alexey Kopytov).
The Fast Index Creation Feature has been disabled by default to align the behavior with upstream. The boolean variable
innodb_expand_fast_index_creation has been introduced for enabling or disabling this feature. Bug Fixed: #858945 (Alexey Kopytov).
- XtraDB requires a full table rebuild for foreign key changes. This unnecessarily delays their creation in a mysqldump output, so
--innodb-optimize-keysshould ignore foreign key constrains. Bug Fixed: #859078 (Alexey Kopytov).
- After adding an index using the Fast Index Creation Feature, statistics for that index provided by XtraDB were left in a bogus state until an explicit
ANALYZE TABLEis executed. Bug Fixed: #857590 (Alexey Kopytov).
QUERY_RESPONSE_TIMEdid not respect
QUERY_RESPONSE_TIME_STATS. Bug Fixed: #855312 (Oleg Tsarev).
- The mysqldump option
--innodb-optimize-keysdid not work correctly with tables where the first
UNIQUEkey on non-nullable columns was picked as the clustered index by XtraDB in the absence of a
PRIMARY KEY. Bug Fixed: #851674 (Alexey Kopytov).
- The Slow Query Log did not log the error number correctly. #830199 (Oleg Tsarev).
log-slow-admin-statementswas not listed with
SHOW VARIABLES. Bug Fixed: #830199 (Oleg Tsarev).
- Fixed assertion failure in XtraDB. Bug Fixed: #814404 (Yasufumi Kinoshita).
AUTO_INCREMENTcolumns must be defined as keys, omitting key specifications and then adding them back in
ALTER TABLEdoesn’t work for them. mysqldump --innodb-optimize-keys has been fixed to take this into account. Bug Fixed: #812179 (Alexey Kopytov).