Oct
30
2017
--

Percona XtraDB Cluster 5.7.19-29.22-3 is now available

Percona XtraDB Cluster 5.7

Percona XtraDB Cluster 5.7Percona announces the release of Percona XtraDB Cluster 5.7.19-29.22-3 on October 27, 2017. Binaries are available from the downloads section or our software repositories.

NOTE: You can also run Docker containers from the images in the Docker Hub repository.

Percona XtraDB Cluster 5.7.19-29.22-3 is now the current release, based on the following:

All Percona software is open-source and free.

Fixed Bugs

  • Added access checks for DDL commands to make sure they do not get replicated if they failed without proper permissions. Previously, when a user tried to perform certain DDL actions that failed locally due to lack of privileges, the command could still be replicated to other nodes, because access checks were performed after replication.This vulnerability is identified as CVE-2017-15365.

Help us improve our software quality by reporting any bugs you encounter using our bug tracking system. As always, thanks for your continued support of Percona!

Oct
30
2017
--

Percona XtraDB Cluster 5.6.37-26.21-3 is Now Available

Percona XtraDB Cluster 5.7

Percona XtraDB Cluster 5.6.34-26.19Percona announces the release of Percona XtraDB Cluster 5.6.37-26.21-3 on October 27, 2017. Binaries are available from the downloads section or our software repositories.

Percona XtraDB Cluster 5.6.37-26.21-3 is now the current release, based on the following:

All Percona software is open-source and free.

Fixed Bugs

  • Added access checks for DDL commands to make sure they do not get replicated if they failed without proper permissions. Previously, when a user tried to perform certain DDL actions that failed locally due to lack of privileges, the command could still be replicated to other nodes, because access checks were performed after replication.This vulnerability is identified as CVE-2017-15365.

Help us improve our software quality by reporting any bugs you encounter using our bug tracking system. As always, thanks for your continued support of Percona!

Sep
22
2017
--

Percona XtraDB Cluster 5.7.19-29.22 is now available

Percona XtraDB Cluster 5.7

Percona XtraDB Cluster 5.7Percona announces the release of Percona XtraDB Cluster 5.7.19-29.22 on September 22, 2017. Binaries are available from the downloads section or our software repositories.

NOTE: You can also run Docker containers from the images in the Docker Hub repository.

Percona XtraDB Cluster 5.7.19-29.22 is now the current release, based on the following:

All Percona software is open-source and free.

Upgrade Instructions

After you upgrade each node to Percona XtraDB Cluster 5.7.19-29.22, run the following command on one of the nodes:

$ mysql -uroot -p < /usr/share/mysql/pxc_cluster_view.sql

Then restart all nodes, one at a time:

$ sudo service mysql restart

New Features

  • Introduced the pxc_cluster_view table to get a unified view of the cluster. This table is exposed through the performance schema.

    mysql> select * from pxc_cluster_view;
    -----------------------------------------------------------------------------
    HOST_NAME  UUID                                  STATUS  LOCAL_INDEX  SEGMENT
    -----------------------------------------------------------------------------
    n1         b25bfd59-93ad-11e7-99c7-7b26c63037a2  DONOR   0            0
    n2         be7eae92-93ad-11e7-88d8-92f8234d6ce2  JOINER  1            0
    -----------------------------------------------------------------------------
    2 rows in set (0.01 sec)
  • PXC-803: Added support for new features in Percona XtraBackup 2.4.7:

    • wsrep_debug enables debug logging
    • encrypt_threads specifies the number of threads that XtraBackup should use for encrypting data (when encrypt=1). This value is passed using the --encrypt-threads option in XtraBackup.
    • backup_threads specifies the number of threads that XtraBackup should use to create backups. See the --parallel option in XtraBackup.

Improvements

  • PXC-835: Limited wsrep_node_name to 64 bytes.
  • PXC-846: Improved logging to report reason of IST failure.
  • PXC-851: Added version compatibility check during SST with XtraBackup:
    • If a donor is 5.6 and a joiner is 5.7: A warning is printed to perform mysql_upgrade.
    • If a donor is 5.7 and a joiner is 5.6: An error is printed and SST is rejected.

Fixed Bugs

  • PXC-825: Fixed script for SST with XtraBackup (wsrep_sst_xtrabackup-v2) to include the --defaults-group-suffix when logging to syslog. For more information, see #1559498.
  • PXC-826: Fixed multi-source replication to PXC node slave. For more information, see #1676464.
  • PXC-827: Fixed handling of different binlog names between donor and joiner nodes when GTID is enabled. For more information, see #1690398.
  • PXC-830: Rejected the RESET MASTER operation when wsrep provider is enabled and gtid_mode is set to ON. For more information, see #1249284.
  • PXC-833: Fixed connection failure handling during SST by making the donor retry connection to joiner every second for a maximum of 30 retries. For more information, see #1696273.
  • PXC-839: Fixed GTID inconsistency when setting gtid_next.
  • PXC-840: Fixed typo in alias for systemd configuration.
  • PXC-841: Added check to avoid replication of DDL if sql_log_bin is disabled. For more information, see #1706820.
  • PXC-842: Fixed deadlocks during Load Data Infile (LDI) with log-bin disabled by ensuring that a new transaction (of 10 000 rows) starts only after the previous one is committed by both wsrep and InnoDB. For more information, see #1706514.
  • PXC-843: Fixed situation where the joiner hangs after SST has failed by dropping all transactions in the receive queue. For more information, see #1707633.
  • PXC-853: Fixed cluster recovery by enabling wsrep_ready whenever nodes become PRIMARY.
  • PXC-862: Fixed script for SST with XtraBackup (wsrep_sst_xtrabackup-v2) to use the ssl-dhparams value from the configuration file.

Help us improve our software quality by reporting any bugs you encounter using our bug tracking system. As always, thanks for your continued support of Percona!

Sep
20
2017
--

Percona XtraDB Cluster 5.6.37-26.21 is Now Available

Percona XtraDB Cluster 5.7

Percona XtraDB Cluster 5.6.34-26.19Percona announces the release of Percona XtraDB Cluster 5.6.37-26.21 on September 20, 2017. Binaries are available from the downloads section or our software repositories.

Percona XtraDB Cluster 5.6.37-26.21 is now the current release, based on the following:

All Percona software is open-source and free.

Improvements

  • PXC-851: Added version compatibility check during SST with XtraBackup:
    • If donor is 5.6 and joiner is 5.7: A warning is printed to perform mysql_upgrade.
    • If donor is 5.7 and joiner is 5.6: An error is printed and SST is rejected.

Fixed Bugs

  • PXC-825: Fixed script for SST with XtraBackup (wsrep_sst_xtrabackup-v2) to include the --defaults-group-suffix when logging to syslog. For more information, see #1559498.
  • PXC-827: Fixed handling of different binlog names between donor and joiner nodes when GTID is enabled. For more information, see #1690398.
  • PXC-830: Rejected the RESET MASTER operation when wsrep provider is enabled and gtid_mode is set to ON. For more information, see #1249284.
  • PXC-833: Fixed connection failure handling during SST by making the donor retry connection to joiner every second for a maximum of 30 retries. For more information, see #1696273.
  • PXC-841: Added check to avoid replication of DDL if sql_log_bin is disabled. For more information, see #1706820.
  • PXC-853: Fixed cluster recovery by enabling wsrep_ready whenever nodes become PRIMARY.
  • PXC-862: Fixed script for SST with XtraBackup (wsrep_sst_xtrabackup-v2) to use the ssl-dhparams value from the configuration file.

Help us improve our software quality by reporting any bugs you encounter using our bug tracking system. As always, thanks for your continued support of Percona!

Jul
05
2017
--

Differences in PREPARE Statement Error Handling with Binary and Text Protocol (Percona XtraDB Cluster / Galera)

PREPARE Statement

PREPARE StatementIn this blog, we’ll look at the differences in how a PREPARE statement handles errors in binary and text protocols.

Introduction

Since Percona XtraDB Cluster is a multi-master solution, when an application executes conflicting workloads one of the workloads gets rolled back with a DEADLOCK error. While the same holds true even if you fire the workload through a PREPARE statement, there are differences between using the MySQL connector API (with binary protocol) and the MySQL client (with text protocol). Let’s look at these differences with the help of an example.

Base Workload

  • Say we have a two-node cluster (n1 and n2) with the following base schema and tables:
    use test;
    create table t (i int, k int, primary key pk(i)) engine=innodb;
    insert into t values (1, 10), (2, 20), (3, 30);
    select * from t;
  • Workload (w1) on node-1 (n1):
    prepare st1 from 'update t set k = k + 100 where i > 1';
    execute st1;
  • Workload (w2) on node-2 (n2):
    prepare st1 from 'update t set k = k + 100 where i > 1';
    execute st1;
  • The workloads are conflicting, and the first node to commit wins. Let’s assume n1 commits first, and the write-set is replicated to n2 while n2 is busy executing the local workload.

Different Scenarios Based on Configuration

wsrep_retry_autocommit > 0
  • n2 tries to apply the replicated workload, thereby forcefully aborting (brute-force abort) the local workload (w2).
  • The forcefully aborted workload is retried (based on wsrep_retry_autocommit value (default is 1)).
  • w2 succeeds on retry, and the new state of table t would be:
    (1, 10), (2, 220), (3, 230);
  • The user can increase wsrep_retry_autocommit to a higher value, though we don’t recommend this as a higher value increases pressure on the system to retry failed workloads. A retry doesn’t ensure things always pass if additional conflicting replicated workload are lined up in the certification queue. Also, it is important to note that a retry works only if
    AUTO_COMMIT=ON

    . For a begin-commit transaction, retry is not applicable. If we abort this transaction, then the complete transaction is rolled back. The workload executor application should have the logic to expect workload failure due to conflict and handle it accordingly.

wsrep_retry_autocommit = 0
  • Let’s say the user sets wsrep_retry_autocommit=0 on node-2 and executes the same workload.
  • This time it doesn’t retry the local workload (w2). Instead, it sends an error to the end-user:
    mysql> execute st1;
    ERROR 1213 (40001): WSREP detected deadlock/conflict and aborted the transaction. Try restarting the transaction
    mysql> select * from t;
    +---+------+
    | i | k |
    +---+------+
    | 1 | 10 |
    | 2 | 120 |
    | 3 | 130 |
    +---+------+
    3 rows in set (0.00 sec)
  • Only the replicated workload (w1) is applied, and local workload w2 fails with a DEADLOCK error.
Use of MySQL Connector API

Now let’s try to execute these workloads through Connector API. Connector API uses a binary protocol, which means it directly invokes the PREPARE statement and executes the statement using dedicated command codes (

COM_STMT_PREPARE

 and

COM_STMT_EXECUTE

).

While the conflicting transaction internal abort remains same, the

COM_QUERY

 command code (text protocol) handling corrects the “query interrupted error” and resets it to “deadlock error” based on the

wsrep_conflict_state

 value. It also has logic to retry the auto-commit enable statement.

This error handling and retry logic is not present when the

COM_STMT_PREPARE

 and

COM_STMT_EXECUTE

 command codes are used. This means the user sees a different error (non-masked error) when we try the same workload through an application using the MySQL Connector API:

Output of application from node-2:
Statement init OK!
Statement prepare OK!
Statement execution failed: Query execution was interrupted
exact error-code to be specific: ER_QUERY_INTERRUPTED - 1317 - "Query execution was interrupted"

As you can see above, the statement/workload execution fails with “Query execution was interrupted” error vs. “deadlock” error (as seen with the normal MySQL client).

Conclusion

While the core execution remains same, error handling is different with text and binary protocol. This issue/limitation was always present, but it’s more prominent since sysbench-1.0 started using the PREPARE statement as a default.

What does this means to end-user/application?

  • Nothing has changed from the Percona XtraDB Cluster perspective, except that if your application is planning to use a binary protocol (like Connector API), then the application should able to handle both the errors and retry the failed transaction accordingly.
Jun
23
2017
--

Percona XtraDB Cluster, Galera Cluster, MySQL Group Replication High Availability Webinar: Q & A

High Availability Webinar

High Availability WebinarThank you for attending the Wednesday, June 21, 2017 high availability webinar titled Percona XtraDB Cluster, Galera Cluster, MySQL Group Replication. In this blog, I will provide answers to the Q & A for that webinar.

You can find the slides and a recording of the webinar here.

Is there a minimum MySQL server version for Group Replication?

MySQL Group Replication is GA since MySQL Community 5.7.17. This is the lowest version that you should use for the Group Replication feature. Otherwise, you are using a beta version.

Since 5.7.17 was the GA release, it’s strongly recommended you use the latest 5.7 minor release. Bugs get fixed and features added in each of the minor releases (as can be seen in the Limitations section in the slide deck).

In MySQL 5.6 and earlier versions, Group Replication is not supported. Note that Percona Server for MySQL 5.7.17 and beyond also ships with Group Replication.

Can I use Percona XtraDB Cluster with MariaDB v10.2? or must I use Percona Server for MySQL?

Percona XtraDB Cluster is Percona Server for MySQL and Percona XtraBackup with the modified Galera library. You cannot run Percona XtraDB Cluster on MariaDB.

However, as Percona XtraDB Cluster is open source, it is possible that MariaDB/Codership implements our modifications into their codebase.

If Percona XtraDB Cluster does not allow InnoDB tables, how do we typically deal with applications that need to use MyISAM tables?

You cannot use MyISAM with Percona XtraDB Cluster, Galera or Group Replication. However, there is experimental MyISAM support in Galera/Percona XtraDB Cluster. But we strongly recommend that you don’t use this in production. It effectively executes all statements in Total Order Isolation, which results in bad performance.

What is a typical business use case for the Group Replication? I specifically like the writes order feature.

Typical use cases are:

  • Environments with strict **durability** requirements
  • Write to multiple nodes simultaneously while keeping data **consistent**
  • Reducing failover time
  • Using other nodes for read-scaling, where reading stale data is more difficult for the application (as opposed to standard asynchronous replication)

The use cases for Galera and Percona XtraDB Cluster are similar.

Where do you run ProxySQL, on a separate server? We are using HAProxy.

You can deploy ProxySQL in many different ways. One common method of installation is to run ProxySQL on a separate layer of servers (ensuring there is failover on this layer). Another commonly used method is to run a ProxySQL daemon on every application server.

Do you support KVM?

Yes, there are no limitations on virtualization solutions.

Can you give some examples of an “arbitrator”?

Some useful links:

What does Percona XtraDB add to make it more performant than InnoDB?

The scalability and performance improvement of Percona XtraDB are listed on the Percona Server for MySQL documentation page: https://www.percona.com/doc/percona-server/LATEST/index.html

How scalable is Percona XtraDB Cluster storage wise? Do we have any limitations?

Storage happens through the storage engine (which is InnoDB). Percona XtraDB Cluster does not have any different limitations than Percona Server for MySQL or MySQL.

However, we need to also consider the practical side of things: the larger the cluster gets, the longer certain operations take. For example, when adding a new node to the cluster another node must be the donor and provide all the data. This will take substantially longer with larger datasets. Certain operational aspects might therefore become more complex.

Is there any development to add multiple nodes simultaneously?

No, at the moment only one node can join the cluster at the same time. Other nodes automatically wait until it is finished before joining.

Why does Galera say we cannot use READ COMMITTED isolation for multimaster mode, even though we can start the cluster with READ-COMMITTED?

You can use READ-COMMITTED as transaction isolation level. The limitation is that you cannot use SERIALIZABLE: http://galeracluster.com/documentation-webpages/isolationlevels.html.

Galera Cluster and MariaDB currently do not prevent a user from using this transaction isolation level. Percona XtraDB Cluster implemented the strict mode to prevent these operations: https://www.percona.com/doc/percona-xtradb-cluster/LATEST/features/pxc-strict-mode.html#explicit-table-locking

MariaDB 10.2 fixed the check constraints issue, When will Percona fix this issue?

There are currently no plans to support CHECK constraints in Percona Server for MySQL (and therefore Percona XtraDB Cluster as well).

As Percona Server is effectively a fully backwards-compatible (but modified) MySQL Community Server, CHECK constraints is a feature that normally would be implemented in MySQL Community first.

Can you share your performance benchmark git repository (if you have one)?

We don’t have a performance benchmark in git repository. You can get detailed information about this benchmark in this blog: Performance improvements in Percona XtraDB Cluster 5.7.17-29.20.

On your slide pointing to scalability charts, how many nodes did you run your test against?

We used a three-node cluster for this performance benchmark.

The product is using Master-Master replication. As such what do you mean when you talk about failover in such configuration?
Where do you maintain the cluster state?

All technologies automatically maintain the cluster state as you add and remove nodes.

What are the network/IP requirements for Proxy SQL?

There are no specific requirements. More documentation about ProxySQL can be found here: https://github.com/sysown/proxysql/wiki.

Jun
02
2017
--

Percona XtraDB Cluster 5.7.18-29.20 is now available

Percona XtraDB Cluster 5.7

Percona XtraDB Cluster 5.7Percona announces the release of Percona XtraDB Cluster 5.7.18-29.20 on June 2, 2017. Binaries are available from the downloads section or our software repositories.

NOTE: You can also run Docker containers from the images in the Docker Hub repository.

NOTE: Due to new package dependency, Ubuntu/Debian users should use apt-get dist-upgrade or apt-get installpercona-xtradb-cluster-57 to upgrade.

Percona XtraDB Cluster 5.7.18-29.20 is now the current release, based on the following:

All Percona software is open-source and free.

Fixed Bugs

  • PXC-749: Fixed memory leak when running INSERT on a table without primary key defined and wsrep_certify_nonPK disabled (set to 0).

    NOTE: We recommend you define primary keys on all tables for correct write-set replication.

  • PXC-812: Fixed SST script to leave the DONOR keyring when JOINER clears the datadir.

  • PXC-813: Fixed SST script to use UTC time format.

  • PXC-816: Fixed hook for caching GTID events in asynchronous replication. For more information, see #1681831.

  • PXC-820: Enabled querying of pxc_maint_mode by another client during the transition period.

  • PXC-823: Fixed SST flow to gracefully shut down JOINER node if SST fails because DONOR leaves the cluster due to network failure. This ensures that the DONOR is then able to recover to synced state when network connectivity is restored For more information, see #1684810.

  • PXC-824: Fixed graceful shutdown of Percona XtraDB Cluster node to wait until applier thread finishes.

Other Improvements

  • PXC-819: Added five new status variables to expose required values from wsrep_ist_receive_status and wsrep_flow_control_interval as numbers, rather than strings that need to be parsed:

    • wsrep_flow_control_interval_low
    • wsrep_flow_control_interval_high
    • wsrep_ist_receive_seqno_start
    • wsrep_ist_receive_seqno_current
    • wsrep_ist_receive_seqno_end

Help us improve our software quality by reporting any bugs you encounter using our bug tracking system. As always, thanks for your continued support of Percona!

Jun
02
2017
--

Percona XtraDB Cluster 5.6.36-26.20 is Now Available

Percona XtraDB Cluster 5.7

Percona XtraDB Cluster 5.6.34-26.19Percona announces the release of Percona XtraDB Cluster 5.6.36-26.20 on June 2, 2017. Binaries are available from the downloads section or our software repositories.

Percona XtraDB Cluster 5.6.36-26.20 is now the current release, based on the following:

All Percona software is open-source and free.

NOTE: Due to end of life, Percona will stop producing packages for the following distributions after July 31, 2017:

  • Red Hat Enterprise Linux 5 (Tikanga)
  • Ubuntu 12.04 LTS (Precise Pangolin)

You are strongly advised to upgrade to latest stable versions if you want to continue using Percona software.

Fixed Bugs

  • PXC-749: Fixed memory leak when running INSERT on a table without primary key defined and wsrep_certify_nonPK disabled (set to 0).

    NOTE: We recommended you define primary keys on all tables for correct write set replication.

  • PXC-813: Fixed SST script to use UTC time format.

  • PXC-823: Fixed SST flow to gracefully shut down JOINER node if SST fails because DONOR leaves the cluster due to network failure. This ensures that the DONOR is then able to recover to synced state when network connectivity is restored For more information, see #1684810.

Help us improve our software quality by reporting any bugs you encounter using our bug tracking system. As always, thanks for your continued support of Percona!

Apr
19
2017
--

Performance improvements in Percona XtraDB Cluster 5.7.17-29.20

Percona XtraDB Cluster

In our latest release of Percona XtraDB Cluster, we’ve introduced major performance improvements to the MySQLwrite-set replication layer. In this post, we want to show what these improvements look like.

For the test, we used the sysbench OLTP_RW, UPDATE_KEY and UPDATE_NOKEY workloads with 100 tables, 4mln rows each, which gives about 100GB of datasize. In all the tests we use a three-node setup, connected via a 10GB network, with the sysbench load directed to the one primary node.

In the first chart, we show improvements comparing to the previous version (5.7.16):

Percona XtraDB Cluster

The main improvements come from concurrent workloads, under multiple threads.

The previous chart is for cases using enabled binary logs, but in some situations we will have deployments without binary logs enabled (Percona XtraDB Cluster does not require them). The latest release significantly improves performance for this case as well.

Here is a chart showing throughput without binary logs:

Percona XtraDB Cluster

Where does Percona XtraDB Cluster place in comparison with similar technologies? To find out, we’ll compare this release with MySQL 5.7.17 Group Replication and with the recently released MariaDB 10.2.5 RC.

For MySQL 5.7.17 Group Replication, I’ve reviewed two cases: “durable” with sync_binlog=1, and “relaxed durability” with sync_binlog=0.

Also for MySQL 5.7.17 Group Replication, we want to review two cases with different flow_control settings. The first setting is flow_control=25000 (the default setting). It provides better performance, but with the drawbacks that non-primary nodes will fall behind significantly and MySQL Group Replication does not provide a way to protect from reading stale data. So with a default flow_control=25000, we risk reading very outdated data. We also tested MySQL Group Replication with flow_control=1000 to minimize stale data on non-primary nodes.

A note on the Flow Control topic: it is worth mentioning that we also changed the flow_control default for Percona XtraDB Cluster. The default value is 100 instead of 16 (as in version 5.7.16).

Comparison chart with sync_binlog=1 (for MySQL Group Replication):

Percona XtraDB Cluster

Comparison chart with sync_binlog=0 (for MySQL Group Replication):

Percona XtraDB Cluster

So there are couple conclusions we can make out of these charts.

  1. The new version of Percona XtraDB Cluster performs on the level with MySQL Group Replication
  2. flow_control for MySQl Group Replication really makes a difference for performance, and default flow_control=25000 is better (with the risk of a lot of outdated data on non-primary nodes)

The reference our benchmark files and config files are here.

Apr
19
2017
--

Percona XtraDB Cluster 5.7.17-29.20 is now available

Percona XtraDB Cluster 5.7

Percona XtraDB Cluster 5.7Percona announces the release of Percona XtraDB Cluster 5.7.17-29.20 on April 19, 2017. Binaries are available from the downloads section or our software repositories.

NOTE: You can also run Docker containers from the images in the Docker Hub repository.

Percona XtraDB Cluster 5.7.17-29.20 is now the current release, based on the following:

All Percona software is open-source and free.

Performance Improvements

This release is focused on performance and scalability with increasing workload threads. Tests show up to 10 times increase in performance.

Fixed Bugs

  • Updated semantics for gcache page cleanup to trigger when either gcache.keep_pages_size or gcache.keep_pages_count exceeds the limit, instead of both at the same time.
  • Added support for passing the XtraBackup buffer pool size with the use-memory option under [xtrabackup] and the innodb_buffer_pool_size option under [mysqld] when the --use-memory option is not passed with the inno-apply-opts option under [sst].
  • Fixed gcache page cleanup not triggering when limits are exceeded.
  • Improved SST and IST log messages for better readability and unification.
  • Excluded the garbd node from flow control calculations.
  • Added extra checks to verify that SSL files (certificate, certificate authority, and key) are compatible before openning connection.
  • Improved parallelism for better scaling with multiple threads.
  • Added validations for DISCARD TABLESPACE and IMPORT TABLESPACE in PXC Strict Mode to prevent data inconsistency.
  • Added the wsrep_flow_control_status variable to indicate if node is in flow control (paused).
  • PXC-766: Added the wsrep_ist_receive_status variable to show progress during an IST.
  • Allowed CREATE TABLE ... AS SELECT (CTAS) statements with temporary tables (CREATE TEMPORARY TABLE ... AS SELECT) in PXC Strict Mode. For more information, see 1666899.
  • PXC-782: Updated xtrabackup-v2 script to use the tmpdir option (if it is set under [sst][xtrabackup] or [mysqld], in that order).
  • PXC-783: Improved the wsrep stage framework.
  • PXC-784: Fixed the pc.recovery procedure to abort if the gvwstate.dat file is empty or invalid, and fall back to normal joining process. For more information, see 1669333.
  • PXC-794: Updated the sockopt option to include a comma at the beginning if it is not set by the user.
  • PXC-795: Set --parallel=4 as default option for wsrep_sst_xtrabackup-v2 to run four threads with XtraBackup.
  • PXC-797: Blocked wsrep_desync toggling while node is paused to avoid halting the cluster when running FLUSH TABLES WITH READ LOCK. For more information, see 1370532.
  • PXC-805: Inherited upstream fix to avoid using deprecated variables, such as INFORMATION_SCHEMA.SESSION_VARIABLE. For more information, see 1676401.
  • PXC-811: Changed default values for the following variables:
    • fc_limit from 16 to 100
    • send_window from 4 to 10
    • user_send_window from 2 to 4
  • Moved wsrep settings into a separate configuration file (/etc/my.cnf.d/wsrep.cnf).
  • Fixed mysqladmin shutdown to correctly stop the server on systems using systemd.
  • Fixed several packaging and dependency issues.

Help us improve our software quality by reporting any bugs you encounter using our bug tracking system. As always, thanks for your continued support of Percona!

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