Percona XtraDB Cluster 5.6.14-25.1¶
Based on Percona Server 5.6.14-62.0 including all the bug fixes in it, Galera Replicator 3.1 and on Codership wsrep API 5.6.14-25.1 is now the first BETA release. All of Percona‘s software is open-source and free, all the details of the release can be found in the 5.6.14-25.1 milestone at Launchpad.
This release contains all of the features and bug fixes in Percona XtraDB Cluster 5.5.34-23.7.6, plus the following:
Percona XtraDB Cluster has implemented a number of XtraDB performance improvements for I/O-bound high-concurrency workloads.
Percona XtraDB Cluster has implemented a number of performance improvements for Page cleaner thread tuning.
ALL_O_DIRECTmethod for innodb_flush_method has been ported from 5.5 version.
Statement Timeout feature has been ported from the Twitter branch.
Percona XtraDB Cluster has extended the
SELECT INTO ... OUTFILEand
SELECT INTO DUMPFILEto add the support for
UNIXsockets and named pipes.
Percona XtraDB Cluster has implemented more efficient log block checksums with new innodb_log_checksum_algorithm variable.
Percona XtraDB Cluster now supports Per-query variable statements.
Limited support for Query Cache has been implemented. Query cache cannot still be fully enabled during the startup. To enable query cache,
mysqldshould be started with
query_cache_size=0and then query_cache_size should be changed to desired value during runtime.
RPMpackages are now made relocatable which means they now support installation to custom prefixes.
Features from Galera¶
Following are salient features of Galera 3:
- new writeset format optimized for performance and reduced memory usage.
- 128-bit writeset checksums, checked every time before writeset is applied, so that corruption cannot sneak in neither on disk, nor in transfer.
- hardware accelerated CRC32-C algorithm for network packets (and ability to turn it off completely). Parameter: socket.checksum.
- improved handling of preordered (read: master-slave replication) events, that preserves original event ID and offers better throughput.
- ability to divide cluster into segments with minimized communication between them to minimize network traffic over WAN. Parameter: gmcast.segment.
SELECT FOR UPDATE...query was aborted due to multi-master conflict, the client wouldn’t get back the deadlock error. From client perspective the transaction would be successful. Bug fixed #1187739.
When installing first
Percona-XtraDB-Cluster-serveron two single statements or a single statement with both packages , yum would install
percona-xtrabackuppackage as dependency of
Percona-XtraDB-Cluster-server. Bug fixed #1226185.
Different mutex implementation in the 5.6 could lead to server assertion error. Bug fixed #1233383.
Server could freeze with mixed DML/DDL load because TOI brute force aborts were not properly propagated. Bug fixed #1239571.
CREATE TABLE AS SELECTwould fail with explicit temporary tables, when binlogging was enabled and
autocommitwas set to
0. Bug fixed #1240098.
Transaction cleanup function did not get called for autocommit statements after rollback, it would stay in
LOCAL_COMMITeven after rollback finished which caused problems when the next transaction started. Bug fixed #1240567.
CREATE TEMPORARY TABLE LIKEwould be replicated and applied in all cluster nodes. This caused temporary table definitions to pile up in slave threads. Bug fixed #1246257.
CREATE TABLE AS SELECTwas not replicated, if the select result set was empty. Bug fixed #1246921.
Write set flags defined in wsrep API are now exposed to application side appliers too. Bug fixed #1247402.
Local brute force aborts are counted accurately. Bug fixed #1247971.
Certain combinations of transaction rollbacks could leave stale transactional
MDLlocks. Bug fixed #1247978.
UNIV_SYNC_DEBUGon, node that was started from clean state would crash immediately at startup. Bug fixed #1248908.
Server built with
UNIV_SYNC_DEBUGwould assert if SQL load has
DELETEstatements on tables with foreign key constraints with
ON DELETE CASCADEoption. Bug fixed #1248921.
Xtrabackup SST dependencies have been added as Optional/Recommended/Suggested dependencies. Bug fixed #1250326.
Other bugs fixed: bug fixed #1020457, bug fixed #1250865, bug fixed #1249753, bug fixed #1248396, bug fixed #1247980, bug fixed #1238278, bug fixed #1234421, bug fixed #1228341, bug fixed #1228333, bug fixed #1225236, bug fixed #1221354, bug fixed #1217138, bug fixed #1206648, bug fixed #1200647, bug fixed #1180792, bug fixed #1163283, bug fixed #1234229, bugs fixed #1250805, bug fixed #1233301, and bug fixed #1210509.
We did our best to eliminate bugs and problems during the testing release, but this is a software, so bugs are expected. If you encounter them, please report them to our bug tracking system.