ProxySQL 2.0.3 and updated proxysql-admin tool

ProxySQL 2.0.3, released by ProxySQL, is now available for download in the Percona Repository along with an updated version of Percona’s proxysql-admin tool.

ProxySQL is a high-performance proxy, currently for MySQL,  and database servers in the MySQL ecosystem (like Percona Server for MySQL and MariaDB). It acts as an intermediary for client requests seeking resources from the database. René Cannaò created ProxySQL for DBAs as a means of solving complex replication topology issues.

The ProxySQL 2.0.3 source and binary packages available from the Percona download page for ProxySQL include ProxySQL Admin – a tool developed by Percona to configure Percona XtraDB Cluster nodes into ProxySQL. Docker images for release 2.0.3 are available as well. You can download the original ProxySQL from GitHub. GitHub hosts the documentation in the wiki format.

With ProxySQL 2.0.3, the proxysql-admin tool now uses the native ProxySQL support for Percona XtraDB Cluster and does not require custom bash scripts to keep track of PXC status.  As a result, proxysql_galera_checker and proxysql_node_monitor have been removed.

Improvements

• The proxysql-admin tool is MySQL 8.0 compatible

Added Features

• New option --use-ssl to use SSL for connections between ProxySQL and the backend database servers
• New option --max-transactions-behind to determine the maximum number of writesets that can be queued before the node is SHUNNED to avoid stale reads. The default value is 100
• New operation --update-cluster to update the cluster membership by adding server nodes as found. (Note that nodes are added but not removed).  The --writer-hg option may be used to specify which galera hostgroup to update. The --remove-all-servers option instructs to remove all servers from the mysql_servers table before updating the cluster.
• Hostgroups can now be specified on the command-line: --writer-hg, --reader-hg, --backup-writer-hg, and --offline-hg.
  Previously, these host groups were only read from the configuration file.
• The --enable and --update-cluster options used simultaneously have special meaning. If the cluster has not been enabled, then --enable is run.  If the cluster has already been enabled, then --update-cluster is run.
• New command --is-enabled to see if a cluster has been enabled. This command checks for the existence of a row in the mysql_galera_hostgroups table.  The --writer-hg option may be used to specify the writer hostgroup used to search the mysql_galera_hostgroups table.
• New command --status to display galera hostgroup information. This command lists all rows in the current mysql_galera_hostgroups table as well as all servers that belong to these hostgroups.  With the --writer-hg option, only the information for the galera hostgroup with that writer hostgroup is displayed.

Changed Features

• Setting --node-check-interval now changes the ProxySQL global variable mysql-monitor_galera_healthcheck_interval
  Note that this is a global variable, not a per-cluster variable.
• The option --write-node now takes only a single address as a parameter. In the singlewrite mode we only set the weight if --write-node specifies address:port.  A priority list of addresses is no longer accepted.
• The option --writers-as-readers option now accepts a different set of values. Due to changes in the behavior of ProxySQL between version 1.4 and version 2.0 related to Galera support, the values of --writers-as-readers have been changed.  This option now accepts the following values: yes, no, and backup.
  yes: writers, backup-writers, and read-only nodes can act as readers.
  no: only read-only nodes can act as readers.
  backup: only backup-writers can act as readers.
• The commands --syncusers, --sync-multi-cluster-users, --adduser, and --disable can now use the --writer-hg option.
• The command --disable removes all users associated with the galera cluster hostgroups. Previously, this command only removed the users with the CLUSTER_APP_USERNAME.
• The command --disable now accepts the --writer-hg option to disable the Galera cluster associated with that hostgroup overriding the value specified in the configuration file.

Removed Features

• Asynchronous slave reader support has been removed: the --include-slaves option is not supported.
• A list of nodes in the priority order is no longer supported. Only a single node is supported at this time.
• Since the galera_proxysql_checker and galera_node_monitor scripts are no longer run in the scheduler, automatic cluster membership updates are not supported.
• Checking the pxc_maint_mode variable is no longer supported
• Using desynced nodes if no other nodes are available is no longer supported.
• The server status is no longer maintained in the mysql_servers table.

Limitations

• With --writers-as-readers=backup read-only nodes are not allowed.
  This a limitation of ProxySQL 2.0.  Note that backup is the default value of --writers-as-readers when --mode=singlewrite

ProxySQL is available under Open Source license GPLv3.