Choosing between Codership's MySQL Galera, MariaDB Galera Cluster and Percona XtraDB Cluster
Download as PPTX, PDF0 likes658 views
The document provides an overview of Galera Cluster, a database clustering software developed by Codership, highlighting its advanced features such as no data loss, scalability, and multi-master replication. It compares different distributions of Galera Cluster, including Codership's MySQL Galera, MariaDB Galera Cluster, and Percona XtraDB Cluster, detailing their unique functionalities and enhancements. Additionally, it discusses upcoming releases, significant features, and options for support from Codership, emphasizing their role as the primary developers of the Galera technology.
Choosing between Codership's MySQL Galera, MariaDB Galera Cluster and Percona XtraDB Cluster
- 1. Choosing between Codershipโs MySQL Galera, MariaDB Galera Cluster and Percona XtraDB Cluster Colin Charles, [email protected] 12 December 2019 https://twitter.com/galeracluster | www.galeracluster.com Codership Webinar
- 2. Agenda โข What is Galera Cluster? โข Who develops Galera Cluster? โข Why are there distributions? โข Understanding the MySQL/MariaDB bases โข Going deeper into the cluster differences โข MySQL 8 + Galera 4
- 3. This is a rare webinarโฆ โข Because we will be introducing and talking about products that arenโt made by Codership, the makers and engineers behind Galera Cluster โข We will talk about the various distributions of Galera Cluster that exist
- 4. What is Linux? โข Linux is a kernel โข There are many distributions of operating systems that include the Linux kernel that you are familiar with โข e.g. Red Hat Enterprise Linux (RHEL), Ubuntu, Fedora, etc.
- 5. What is Galera Cluster? โข It is an advanced database clustering software that provides for no data loss, great uptime, and scalability for growth โข It is truly multi-master based on (virtually) synchronous replication โข This is the solution for High Availability
- 6. Soโฆ what is Galera then? โข A generic replication plugin for database servers โข Uses the replication API to interact with a DBMS (via the wsrep API project, fully open source on GitHub) โข wsrep == writeset replication โข The database and Galera plugin must have the same wsrep API version
- 7. Who developed it? โข The developers and experts of Galera Cluster โข Established in 2007, 3 founders, all engineers โข Seppo Jaakola, CEO, Teemu Ollakka, CTO, Alex Yurchenko, architect โข Services business model, producing 100% open source software โข Thousands of users in various industries: e-commerce, betting/gambling, telecoms, banking, insurance, gaming, healthcare, media, marketing, advertising, travel, education, SaaS, PaaS, IaaS, etc.
- 8. Why are there distributions then? โข Because like Linux, the MySQL ecosystem is wide and varied โข Codership chooses to make a MySQL version, currently for 5.5, 5.6 and 5.7 (with 8.0 coming) โข Codership works closely with MariaDB Corporation to make MariaDB Galera Cluster โข Percona has a branch (fork?) that ports changes from the MariaDB tree, as well as the Codership tree
- 9. What is different at the base?
- 10. Codership MySQL Galera Cluster โข MySQL base version + Galera Cluster โข The latest, greatest, Galera Cluster โข Codership plans the roadmaps of Galera Cluster and the new features, bug fixes, etc. โข This is the most โpristineโ and naturally recommended version of Galera Cluster to use :-)
- 11. Percona Server for MySQL โข Percona Server for MySQL builds on top of MySQL, aims always to be a more performant branch of MySQL โข Has some features that are not present in MySQL: โข MyRocks, TokuDB storage engines (not usable with Galera Cluster), more instrumentation around user statistics, slow query logging, improved MEMORY engine (not usable with Galera Cluster), parallel InnoDB doublewrite buffer (XtraDB), compressed columns with dictionaries, PAM authentication plugin, audit plugin, Vault plugin for encryption, changed page tracking in InnoDB, extended SHOW GRANTS, kill idle transactions, etc.
- 12. MariaDB Server โข Feature compatible, drop-in replacement, fork of MySQL โข So many storage engines! (e.g. MyRocks, Aria, TokuDB, CONNECT, SPIDER) โข Better for DBAs, e.g. group commit in binlog, parallel replication, support for Oracle syntax, table elimination, and a whole lot more โข It is a database by itself in itโs own right!
- 13. MariaDB Server II โข Oracle compatibility (including SEQUENCES, PL/SQL) โข More storage engines but also a completely new (forked) InnoDB โข Temporal data via system versioned tables โข Galera Cluster 4.0! โข Security improvements and changes โข Optimiser improvements โข Replication & Backup โข Compression โข Invisible columns โข Instant ADD COLUMN โข Plus some of the features from 10.2+10.1+10.0+5.5+5.3+5.2+5.1 that may not be in stock MySQL
- 14. Soโฆ what about the Galera Cluster enhancements? โข Percona XtraDB Cluster (PXC) and MariaDB Galera Cluster build on-top of their existing changes and embed the wsrep library, and provide for Galera Cluster in their own distributions โข So in a way, you get the ability to use the threadpool with MariaDB Galera Cluster (the core server features are also exposed when the replication library itself gets replaced) โข SQL_MODE=ORACLE will continue parsing whatever Oracle/PL/SQL that MariaDB Server can parse, with a Galera Cluster backend too! โข Possibilities are endless when you start thinking about future SPIDER support with Galera Cluster
- 15. Percona XtraDB Cluster (PXC) โข Integrated Percona XtraBackup โข Integrated ProxySQL as a load balancer/proxy (with configuration script) โข โStrict Modeโ, e.g. disallow MyISAM, tables without primary keys, ROW binlog_format, logging to a file (not tables), innodb_autoinc_lock_mode set to 2, etc. โข Automatic configuration of SSL encryption (pxc-encrypt-cluster-traffic variable) โข InnoDB improvements (via XtraDB) around full-text search, page fragmentation counters โข Integration with Percona Monitoring & Management (PMM) โข Encryption via keyring_vault or keyring_file plugins (considered beta)
- 16. MariaDB Galera Cluster โข Fully integrated into MariaDB Server (all in one download) โข Only one shipping with Galera 4 (MariaDB 10.4 โ before that Galera 3) โข Can do rolling upgrades from Galera 3 to Galera 4 โข Hint of new Galera 4 features exist: โข Streaming replication (support for large transactions) โข Group commit support โข Use of backup locks (mariabackup SST with a โlightweight lockโ) โข Everything in MariaDB Server is available to use in Galera Cluster (as long as Galera supports it, so not the SPIDER engine, etc.)
- 17. Branch variants
- 18. Some feature highlights of Galera 3.x and 4 โข Intelligent donor selection, preferring a donor that can do an Incremental State Transfer (IST) โข Cluster crash recovery, say, after a power failure via pc.recovery=ON so all nodes maintain cluster information persistently, not requiring a bootstrap โข Streaming replication, which replicates transactions of any size; transaction replicated in small increments. Huge transaction support! โข Consistency voting protocol in the event of inconsistencies, all nodes vote when such is detected โข DDL optimisation, so the lock only applies to the affected table
- 19. Galera replication versions โข There have been many major releases (1,2,3) โข Current production head is at 3.26 โข There have been many wsrep API versions (1..25) โข Next major version is wsrep API 26 which corresponds with Galera 4 โข There are wsrep API changes that require you to perform a rolling upgrade
- 20. MySQL 8 + Galera 4 โข This is to be released Q1/2020 โข I have already been playing with an internal beta on CentOS 7 โข We are working out some bugs, but it will be done soon! โข MySQL GTID sequence numbers are generated from Galera seqno, so there can be holes in the streaming replication fragments, rolled back transactions or transactions with failed certification โข wsrep_cluster_address must be set in mysqld_bootstrap script (easyfix) โข X Protocol/Plugin is not supported yet (but is working in a tree already, so you can query with Python/JavaScript in theory)
- 21. Streaming Replication โข The base for supporting huge transactions โข In Galera Cluster 3, a transaction processes on the โmaster nodeโ (i.e. node that client connected to, to execute the transaction) until commit time โข For large transactions, the writeset will be large, hard to process โข So wsrep_max_ws_size exists to prevent large transactions
- 22. Streaming Replication โข This is new in Galera Cluster 4 to enable running transactions of unlimited size in a cluster โข You can of course still reject large transactions
- 23. What is a large transaction? โข LOAD DATA that is largeโฆ? โข wsrep_max_ws_rows and wsrep_max_ws_size. Limit the transaction rows to 128 KB and the transaction size to 1 GB. wsrep_max_ws_size has a maximum upper limit of 2GB, beyond which it is rejected โข Guide to handle large transactions: http://galeracluster.com/library/kb/best/large-transactions.html including the use of pt-archiver โข One practical test: https://www.percona.com/blog/2015/10/26/how-big-can- your-galera-transactions-be/
- 24. Streaming Replication โข Transactions are replicated, gradually in small fragments, during transaction processing โข i.e. before an actual commit, Galera replicates a number of small sized fragments (transaction fragmentation) โข Size threshold for fragment replication is configurable โข Replicated fragments are applied in slave threads preserving the transaction state in all cluster nodes โข fragments hold locks in all nodes and cannot be conflicted later โข Streaming replication allows nodes to process writesets greater than 2GB
- 25. Configuring Streaming Replication โข Session variables (dynamic): โข wsrep_trx_fragment_unit โ unit metrics for fragmenting, options are bytes (writesets in bytes), rows (number of rows modified), statements (number of SQL statements issued) โข wsrep_trx_fragment_size โ threshold size in units when fragments will be replicated. 0 means no streaming.
- 26. Using Streaming Replication โข Due to excessive logging and elevated replication overhead, streaming replication will cause degraded transaction throughput rate โข Best use case? Use streaming replication to cut large transactions โข Set the fragment size to around 10,000 rows โข Applications can also set streaming replication on/off on a need-by-need basis (requires changes to application naturally)
- 27. New metadata โ wsrep tables in mysql database โข There are some new Galera Cluster system tables SHOW TABLES FROM mysql LIKE 'wsrep%'; +---------------------------+ | Tables_in_mysql (wsrep%) | +---------------------------+ | wsrep_cluster | | wsrep_cluster_members | | wsrep_streaming_log | +---------------------------+
- 28. wsrep_cluster โข Contains current view of the cluster, some identity information and also cluster capabilities SELECT COLUMN_NAME FROM information_schema.columns WHERE table_schema='mysql' AND table_name='wsrep_cluster'; +------------------+ | COLUMN_NAME | +------------------+ | cluster_uuid | | view_id | | view_seqno | | protocol_version | | capabilities | +------------------+
- 29. wsrep_cluster_members SELECT * FROM mysql.wsrep_cluster_members ORDER BY node_name G *************************** 1. row *************************** node_uuid: e39d1774-7e2b-11e9-b5b2-7696f81d30fb cluster_uuid: bd5fe1c3-7d80-11e9-8913-4f209d688a15 node_name: galera1 node_incoming_address: AUTO *************************** 2. row *************************** node_uuid: eb8fc512-7e2b-11e9-bb74-3281cf207f60 cluster_uuid: bd5fe1c3-7d80-11e9-8913-4f209d688a15 node_name: galera2 node_incoming_address: AUTO *************************** 3. row *************************** node_uuid: 2347a8ac-7e2c-11e9-b6f0-da90a2d0a563 cluster_uuid: bd5fe1c3-7d80-11e9-8913-4f209d688a15 node_name: galera3 node_incoming_address: AUTO
- 30. wsrep_streaming_log โข contains meta data and row events for ongoing streaming transactions, writeset fragment per row โข SELECT * FROM mysql.wsrep_streaming_log G
- 31. wsrep functions โข WSREP_LAST_SEEN_GTID() โ returns GTID for last written transaction observed by client โข WSREP_LAST_WRITTEN_GTID() โ returns GTID of the last write transaction made by the client โข WSREP_SYNC_WAIT_UPTO_GTID() โ blocks the client until the node applies and commits the given transaction
- 32. gcache encryption โข Today the logs are all completely encrypted with the exception of the gcache โข ibdata, redo log, binlog, etc. โข now the gcache can also be encrypted
- 33. Non-blocking DDL โข Supremely important, lots of people want this, e.g. shared hosting companies โข Need to upgrade a WordPress database? Lock all writes on all databases served on the cluster when you run wp-upgrade.php
- 34. Percona XtraDB Cluster (PXC) 8? โข Yes, there is a branch of this, early release, based on porting from MariaDB Server 10.4 โข It does not have all the features of MySQL 8 + Galera 4 that come from Codership (yet)
- 35. In summary โข Who are the developers of Galera Cluster? Codership. โข Who has the most developers of Galera Cluster? Codership. โข Who knows the code better than anyone? Codership. โข Who decides the roadmap for Galera Cluster? Codership. With our main partner, MariaDB Corporation, and listening closely to the community.
- 36. Codershipโฆ โข Buy from us! โข We have great 24/7 support plans, consulting, training, remote DBA, etc. โข Speak to our friendly sales consultants! โข P/S: If there are features you would like to see, speak to us. We are more than happy to want to implement them
- 37. Questions? Colin Charles, [email protected] https://twitter.com/galeracluster | www.galeracluster.com 37