Based on Percona Server 5.6.21-70.1 including all the bug fixes in it, Galera Replicator 3.8 and on Codership wsrep API 25.7 is now the current General Availability release. All of Percona‘s software is open-source and free, all the details of the release can be found in the 5.6.21-25.8 milestone at Launchpad.
Galera 3.8 introduces auto-eviction for nodes in the cluster experiencing network issues like packet loss. It is off by default and is turned on with
evs.auto_evictoption. This feature requires EVS protocol version (
1. During the EVS protocol upgrade all membership changes are communicated over EVS protocol version
0to preserve backwards compatibility, protocol is upgraded to the highest commonly supported version when forming a new group so if there exist a single node with older version in the group, the group protocol version remains as
0and auto-eviction is not functional. (#1274192).
Percona XtraDB Cluster now supports backup locks in XtraBackup SST (in the default
wsrep_sst_method). Backup locks are used in lieu of
FLUSH TABLES WITH READ LOCKon the donor during SST. This should allow for minimal disruption of existing and incoming queries, even under high load. Thus, this should allow for even faster SST and node being in ‘donor/desynced’ state. This also introduces following constraints: Percona XtraDB Cluster 5.6.21 requires Percona XtraBackup 2.2.5 or higher; An older (< 5.6.21) joiner cannot SST from a newer (>= 5.6.21) donor. This is enforced through SST versioning (sent from joiner to donor during SST) and logged to error log explicitly. (#1390552).
Percona XtraDB Cluster is now shipped with Galera MTR test suite.
Percona XtraDB Cluster now shows a warning in case additional utilities, like
pvwhich may not affect critical path of SST, are not installed. Bug fixed #1248688.
UNIV_DEBUGbuild failures. Bug fixed #1384413.
Normal shutdown under load would cause server to remain hanging because replayer failed to finish. Bug fixed #1358701.
lock != ctx->wait_lockhas been fixed. Bug fixed #1364840.
garbdwould not work when cluster address was specified without the port. Bug fixed #1365193.
Fixed wsrep options compiler warnings in Fedora 20. Bug fixed #1369916.
mysqldgets killed during the SST it will leave an unclean data directory behind. This would cause Percona XtraDB Cluster to fail when the server would be started next time because the data directory would be corrupted. This was fixed by resuming the startup in case
wsrep-recoverfailed to recover due to corrupted data directory. The old behavior is still achievable through
--exit-on-recover-failcommand line parameter to
my.cnf. Bug fixed #1378578.
Percona XtraDB Cluster now reads environment variables for mysqld from following files (if present): /etc/default/mysql in Debian/Ubuntu;
/etc/sysconfig/mysqlin CentOS 6 or lower;
/etc/sysconfig/mysqlin CentOS 7 with
/etc/sysconfig/XYZin CentOS 7 with
/etc/sysconfig/bootstrapis supplied by default). Bug fixed #1381492.
Percona XtraDB Cluster now detects older joiners which don’t have the backup lock support. Bug fixed #1390552.
wsrep-recoveris now handled gracefully in Debian init scripts rather than returning immediately with a false positive fail.
wsrep-recoverlog is now also written to mysql error log now.
Issue with stale PID files and Debian init script have been fixed now. It now emits a warning for stale PID files.
sst_in_progressfile is not removed anymore in case of failed SST.
In case stored procedure containing a non-InnoDB statement (MyISAM) performed autocommit, that commit would be entered two times: at statement end and next time at stored procedure end. Bug fixed #2.
Two appliers conflicting with local transaction and resulting later in (acceptable) BF-BF lock conflict, would cause cluster to hang when the other BF thread would not grant the lock back after its local transaction got aborted. Bug fixed #7.
Bootstrapping a node tried to resolve gcomm address list specified in
wsrep-cluster-address. Bug fixed #88.
xtrabackup-v2SST did not clean the undo log directory. Bug fixed #1394836.
Inserts to a table with autoincrement primary key could result in duplicate key error if another node joined or dropped from the cluster during the insert processing. Bug fixed #1366997.
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