![30
www.galeracluster.com
wsrep Tables in mysql database
MariaDB [(none)]> show tables in mysql like 'wsrep%';
+--------------------------+
| Tables_in_mysql (wsrep%) |
+--------------------------+
| wsrep_cluster |
| wsrep_cluster_members |
| wsrep_streaming_log |
+--------------------------+
3 rows in set (0.005 sec)](https://image.slidesharecdn.com/openworks19galera4-190313164653/85/What-s-new-in-Galera-4-30-320.jpg)
![31
www.galeracluster.com
wsrep Tables in mysql database
MariaDB [(none)]> select * from mysql.wsrep_clusterG
*************************** 1. row ***************************
cluster_uuid: 0be6f4d6-35da-11e9-b8a0-d6501fb08579
view_id: 2
view_seqno: 2
protocol_version: 4
capabilities: 184703
1 row in set (0.005 sec)](https://image.slidesharecdn.com/openworks19galera4-190313164653/85/What-s-new-in-Galera-4-31-320.jpg)
![32
www.galeracluster.com
wsrep Tables in mysql database
MariaDB [(none)]> select * from mysql.wsrep_cluster_membersG
*************************** 1. row ***************************
node_uuid: ea306990-35b0-11e9-9841-366f30fba24f
cluster_uuid: ea317655-35b0-11e9-9ac4-9f27c3510851
node_name: labrador
node_incoming_address: 127.0.0.1:16000
*************************** 2. row ***************************
node_uuid: eb29a68c-35b0-11e9-ac23-e2418aae257d
cluster_uuid: ea317655-35b0-11e9-9ac4-9f27c3510851
node_name: poodle
node_incoming_address: 127.0.0.1:16001
*************************** 3. row ***************************
node_uuid: eb29e56c-35b0-11e9-a328-fe229f8ae4cb
cluster_uuid: ea317655-35b0-11e9-9ac4-9f27c3510851
node_name: rotweiler
node_incoming_address: 127.0.0.1:16002
3 rows in set (0.006 sec)](https://image.slidesharecdn.com/openworks19galera4-190313164653/85/What-s-new-in-Galera-4-32-320.jpg)
![33
www.galeracluster.com
wsrep Tables in mysql database
MariaDB [(none)]> show create table mysql.wsrep_streaming_logG
*************************** 1. row ***************************
Table: wsrep_streaming_log
Create Table: CREATE TABLE `wsrep_streaming_log` (
`node_uuid` char(36) NOT NULL,
`trx_id` bigint(20) NOT NULL,
`seqno` bigint(20) NOT NULL,
`flags` int(11) NOT NULL,
`frag` longblob NOT NULL,
PRIMARY KEY (`node_uuid`,`trx_id`,`seqno`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1
1 row in set (0.004 sec)](https://image.slidesharecdn.com/openworks19galera4-190313164653/85/What-s-new-in-Galera-4-33-320.jpg)
Uploaded byMariaDB plc
What’s new in Galera 4
The document provides an overview of Galera 4 integration in MariaDB 10.4, highlighting features such as streaming replication, support for large transactions, and new API changes. It outlines the benefits of Galera's synchronous multi-master replication, including no data loss and no slave lag. The document also mentions the roadmap for future features and the process for upgrading from previous Galera versions.
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What’s new in Galera 4
- 1. Galera 4 inMariaDB 10.4 Seppo Jaakola Codership
- 2. 2 www.galeracluster.com ➢ Seppo Jaakola ➢ One ofthe Founders of Codership ➢ Codership – Galera Replication developers ➢ Partner of MariaDB for developing and supporting MariaDB Galera Cluster ➢ Galera releases since 2009
- 3. 3 www.galeracluster.com Agenda ● Galera Cluster Overview ● Galera4 in 10.4 Features ● Upgrading 10.3 Cluster to 10.4 ● Galera 4 Streaming Replication ● Additional Galera 4 Feature Road Map
- 4. 4 www.galeracluster.com MariaDB MariaDB MariaDB SynchronousMulti-Master Replication Galera Replication Replication is synchronous read & write read & write read & write Client can connect to any node There can be several nodes Read & write access to any node
- 5. 5 www.galeracluster.com MariaDB Synchronous Multi-Master Replication a Multi-mastercluster looks like one big database with multiple entry points read & write read & write read & write
- 6. 6 www.galeracluster.com MariaDB Synchronous Multi-Master Replication a Addingmore nodes Opens new connection ports read & write read & writeread & write read & write
- 7. 7 www.galeracluster.com Galera Cluster ➢ Good Performance ➢ Optimisticconcurrency control ➢ Parallel Replication ➢ Optimized Group Communication ➢ 99.99% transparent ➢ InnoDB look & feel ➢ Automatic node joining ➢ Works in LAN / WAN / Cloud
- 8. 8 www.galeracluster.com Galera Cluster ➢ Synchronous multi-mastercluster ➢ no data loss ➢ no slave lag ➢ no slave failover ➢ For MySQL/InnoDB ➢ 3 or more nodes needed for HA ➢ No single point of failure
- 9. 9 www.galeracluster.com Galera Replication Plugin DBMS wsrepprovider GCS framework replication wsrep hookswsrep API certification vsbes gcommspread Galera Plugin v25 v25
- 10. Galera Version 4in MariaDB 10.4
- 11. 11 www.galeracluster.com Galera 4 inMariaDB 10.4 ● MariaDB 10.4 RC has Galera 4 Replication ● 10.4 other features shown in other presentations ● wsrep API #26 ● Impacts upgrading ● wsrep patch integration in 10.4 codebase ● Impacts code stability ● bug fi & new features turnover
- 12. 12 www.galeracluster.com Galera 4 inMariaDB 10.4 ● Streaming Replication ● Support for large transactions ● Platform for other new features ● Group commit support ● 10.4 Backup locks ● mariabackup SST with “light weight lock”
- 13.
- 14. 14 www.galeracluster.com Huge Transaction Support ● InGalera 3, transaction processes in master node until commit time ● For large transactions, the write size will be big, and is hard to handle ● There are means to prevent too large transactions ● wsrep_mai_ws_size
- 15. 15 www.galeracluster.com Streaming Replication ● Streaming replicationis new technology developed for Galera Replication 4 to enable running transaction of unlimited size in cluster ● Transaction size limits will remain, and cluster can still reject too large transactions
- 16. 16 www.galeracluster.com Streaming Replication ● Transaction isreplicated, gradually in small fragments, during transaction processing ● i.e. before actual commit, we replicate a number of small size fragments ● Size threshold for fragment replication is confgurable ● Replicated fragments are applied in slave threads preserving transactions in all cluster nodes ➔ Fragments hold locks in all nodes and cannot be conficted later
- 17. 17 www.galeracluster.com Streaming Replication Huge transaction GaleraReplication Node A Node B Huge trx Update, update, update.... Begin
- 18. 18 www.galeracluster.com Streaming Replication Huge transaction GaleraReplication Node A Node B Huge trx WS Update, update, update....
- 19. 19 www.galeracluster.com Streaming Replication Huge transaction GaleraReplication Node A Node B Huge trx WS Update, update, update....
- 20. 20 www.galeracluster.com Streaming Replication Huge transaction GaleraReplication Node A Node B Huge trx WS commit
- 21. 21 www.galeracluster.com Streaming Replication Huge transaction GaleraReplication Node A Node B OK
- 22. 22 www.galeracluster.com Fragment Applying SR transactionpool SR#1 THD SR#2 THD SR#n THD WS SR trx :2 CF: 0 applier applier applier certification
- 23. 23 www.galeracluster.com applier Fragment Applying SR transactionpool SR#1 THD SR#2 THD SR#n THD WS SR trx :2 CF: 0 applier applier ev→apply_event() … ev->apply_event() wsrep_SR_store->append_frag_apply())
- 24. 24 www.galeracluster.com Fragment Applying SR transactionpool SR#1 THD SR#2 THD SR#n THD applier applier applier
- 25. 25 www.galeracluster.com Fragment Applying SR transactionpool SR#1 THD SR#2 THD SR#n THD WS SR trx :2 CF: 1 applier applier applier certification
- 26. 26 www.galeracluster.com applier Fragment Applying SR transactionpool SR#1 THD SR#2 THD SR#n THD WS SR trx :2 CF: 1 applier applier trans_commit() wsrep_SR_store->append_frag_commit())
- 27. 27 www.galeracluster.com Configuring Streaming Replication wsrep_trx_fragment_unitUnit metrics for fragmenting, options are: ● bytes WS size in bytes ● rows # of rows modified ● statements # of SQL statements issued wsrep_trx_fragment_size ● Threshold size (in units), when fragment will be replicated ● 0 = no streaming ● Session variables and can be dynamically set
- 28. 28 www.galeracluster.com Using Streaming Replication ● Dueto excessive logging and elevated replication overhead, streaming replication will cause degraded transaction throughput rate ● Best use case is to use streaming replication for cutting large transactions ● Set fragment size to ~10K rows ● Fragment variables are session variables and can be dynamically set ● Intelligent application can set streaming replication on/off on need basis
- 29.
- 30. 30 www.galeracluster.com wsrep Tables inmysql database MariaDB [(none)]> show tables in mysql like 'wsrep%'; +--------------------------+ | Tables_in_mysql (wsrep%) | +--------------------------+ | wsrep_cluster | | wsrep_cluster_members | | wsrep_streaming_log | +--------------------------+ 3 rows in set (0.005 sec)
- 31. 31 www.galeracluster.com wsrep Tables inmysql database MariaDB [(none)]> select * from mysql.wsrep_clusterG *************************** 1. row *************************** cluster_uuid: 0be6f4d6-35da-11e9-b8a0-d6501fb08579 view_id: 2 view_seqno: 2 protocol_version: 4 capabilities: 184703 1 row in set (0.005 sec)
- 32. 32 www.galeracluster.com wsrep Tables inmysql database MariaDB [(none)]> select * from mysql.wsrep_cluster_membersG *************************** 1. row *************************** node_uuid: ea306990-35b0-11e9-9841-366f30fba24f cluster_uuid: ea317655-35b0-11e9-9ac4-9f27c3510851 node_name: labrador node_incoming_address: 127.0.0.1:16000 *************************** 2. row *************************** node_uuid: eb29a68c-35b0-11e9-ac23-e2418aae257d cluster_uuid: ea317655-35b0-11e9-9ac4-9f27c3510851 node_name: poodle node_incoming_address: 127.0.0.1:16001 *************************** 3. row *************************** node_uuid: eb29e56c-35b0-11e9-a328-fe229f8ae4cb cluster_uuid: ea317655-35b0-11e9-9ac4-9f27c3510851 node_name: rotweiler node_incoming_address: 127.0.0.1:16002 3 rows in set (0.006 sec)
- 33. 33 www.galeracluster.com wsrep Tables inmysql database MariaDB [(none)]> show create table mysql.wsrep_streaming_logG *************************** 1. row *************************** Table: wsrep_streaming_log Create Table: CREATE TABLE `wsrep_streaming_log` ( `node_uuid` char(36) NOT NULL, `trx_id` bigint(20) NOT NULL, `seqno` bigint(20) NOT NULL, `flags` int(11) NOT NULL, `frag` longblob NOT NULL, PRIMARY KEY (`node_uuid`,`trx_id`,`seqno`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 1 row in set (0.004 sec)
- 34.
- 35. 35 www.galeracluster.com Galera 3 Galera RollingUpgrades Galera Replication read & write MariaDB 10.3 Galera 3 read & write MariaDB 10.3 Galera 3 MariaDB 10.3 Wsrep-API 25 read & write
- 36. 36 www.galeracluster.com Galera 3 Galera RollingUpgrades Galera Replication read & write MariaDB 10.3 Galera 3 read & write MariaDB 10.3 Galera 3 MariaDB 10.3 Wsrep-API 25 Upgrade for 10.4 Shutdown server Install 10.4 Start with wsrep_provider mysql_upgrade Shutdown server Start without wsrep_provider Isolate node Galera 4 Galera 4 MariaDB 10.4 Allow read only access read only
- 37. 37 www.galeracluster.com Galera 3 Galera RollingUpgrades Galera Replication read & write MariaDB 10.3 Galera 3 MariaDB 10.3 Wsrep-API 25 Galera 4 MariaDB 10.4 read only Galera 4 MariaDB 10.4 read only Upgrade for 10.4 Upgrade node 2
- 38. 38 www.galeracluster.com Galera 3 Galera RollingUpgrades Galera Replication read & write MariaDB 10.3 Wsrep-API 25 Galera 4 MariaDB 10.4 read only Galera 4 MariaDB 10.4 read only Wsrep-API 26 read & write read & write Upgrade for 10.4 Shutdown node 1 Allow read-write Complete node1 upgrade wsrep API #26 features now Enabled in replication
- 39. 39 www.galeracluster.com Galera Rolling Upgrades GaleraReplication read & write Wsrep-API 25 Galera 4 MariaDB 10.4 read only Galera 4 MariaDB 10.4 read only Wsrep-API 26 read & write read & write Galera 4 MariaDB 10.4
- 40. 40 www.galeracluster.com Galera Rolling Upgrades GaleraReplication read & write Wsrep-API 25 Galera 4 MariaDB 10.4 read only Galera 4 MariaDB 10.4 read only Wsrep-API 26 read & write read & write Galera 4 MariaDB 10.4 join Galera 3 MariaDB 10.3
- 41.
- 42. 42 www.galeracluster.com 4.0 Release Status ● Partof Galera 4 feature set was merged in MariaDB 10.4 beta 2 release and is now in the new 10.4 RC release ● Schedule of remaining Galera 4 features is not yet confrmed
- 43. 43 www.galeracluster.com Features Missed inMariaDB 10.4 ● Gcache encryption ● Data at rest encryption for full replication pipeline ● XA transaction support ● Will be needed in sharding cluster ● Non blocking DDL ● Co-incides with other MariaDB non-locking DDL work ● Cluster error voting ● Galera library feature, may be in later 10.4.* releases
- 44. 44 www.galeracluster.com R A M Data at restencryption Client thread Client threadClient thread Buffer pool gcache ibdataibdata redo logredo log redo logbinlog D I S K
- 45. 45 www.galeracluster.com R A M Data at restencryption Client thread Client threadClient thread Buffer pool gcache D I S K ibdataibdata redo logredo log redo logbinlog
- 46. 46 www.galeracluster.com R A M Data at restencryption Client thread Client threadClient thread Buffer pool gcache D I S K ibdataibdata redo logredo log redo logbinlog
- 47. 47 www.galeracluster.com Features Missed inMariaDB 10.4 ● Gcache encryption ● Data at rest encryption for full replication pipeline ● XA transaction support ● Will be needed in sharding cluster ● Non blocking DDL ● Co-incides with other MariaDB non-locking DDL work ● Cluster error voting ● Galera library feature, may be in later 10.4.* releases
- 48. XA Transaction Support InGalera 3
- 49. 49 www.galeracluster.com XA Transactions withGalera 3 TM RM RM XA start ‘foo’ XA start ‘bar’ foo bar Work on ‘foo’ Work on ‘bar’XA prepare ‘foo’ XA prepare ‘bar’XA commit ‘foo’ XA commit ‘bar’ foo bar MariaDB
- 50. 50 www.galeracluster.com XA Transactions withGalera 3 ● Galera replication is eager to replicate in MariaDB 2PC prepare stage ● Prepared XA transaction cannot be rolled back anymore
- 51. 51 www.galeracluster.com XA Transactions withGalera 3 XA Start Node A Node B smith smith XA trans
- 52. 52 www.galeracluster.com XA Transactions withGalera 3 XA Insert into persons ‘’jones’ Node A Node B smith smith jones XA trans
- 53. 53 www.galeracluster.com XA Transaction Support XAPrepare Node A Node B smith smith jones XA trans
- 54. 54 www.galeracluster.com XA Transaction Support XAPrepare Node A Node B smith smith jones XA trans WS jones
- 55. 55 www.galeracluster.com XA Transaction Support XAPrepare Node A Node B smith smith jones jones XA trans apply
- 56. 56 www.galeracluster.com XA Transaction Support OK NodeA Node B smith smith jones jones XA trans
- 57. 57 www.galeracluster.com XA Transaction Support XARollback Node A Node B smith Smith jones jones XA trans
- 58. 58 www.galeracluster.com XA Transaction Support NodeA Node B smith smith jonesinconsistency
- 59. 59 www.galeracluster.com XA prepare Safety ● XAprepare should guarantee that transaction can commit ● However, galera multi-master confict resolving does honor XA transactions
- 60. 60 www.galeracluster.com XA Transactions withGalera 3 XA Start Node A Node B smith smith XA trans
- 61. 61 www.galeracluster.com XA Transactions withGalera 3 UPDATE smith=kit Node A Node B smith smith XA trans
- 62. 62 www.galeracluster.com XA Transactions withGalera 3 Node A Node B smith smith XA trans WS jones UPDATE smith=hannibal WS hannibal XA Prepare
- 63. 63 www.galeracluster.com XA Transactions withGalera 3 Node A Node B hannibal hannibal XA trans OK
- 64. XA Transaction Supportby Streaming Replication
- 65. 65 www.galeracluster.com XA Transaction Support XAStart Node A Node B smith smith XA trans
- 66. 66 www.galeracluster.com XA Transaction Support XAInsert into persons ‘’jones’ Node A Node B smith smith XA transXA transXA transXA trans jones
- 67. 67 www.galeracluster.com XA Transaction Support XAPrepare Node A Node B smith smith XA trans SR trans WS jonesjones
- 68. 68 www.galeracluster.com XA Transaction Support XARollback Node A Node B smith Smith jones XA trans SR trans WS rollback jonesjones
- 69. 69 www.galeracluster.com XA Transaction Support NodeA Node B smith Smith
- 70. 70 www.galeracluster.com Features Missed inMariaDB 10.4 ● Gcache encryption ● Data at rest encryption for full replication pipeline ● XA transaction support ● Will be needed in sharding cluster ● Non blocking DDL ● Co-incides with other MariaDB non-locking DDL work ● Cluster error voting ● Galera library feature, may be in later 10.4.* releases
- 71. 71 www.galeracluster.com Summary ● MariaDB 10.4.3 hassignifcant new Galera 4 features ● Streaming Replication implements new replication protocol opening possibilities for many unforeseen replication features ● Other new Galera 4 related features to come with later 10.4 or 10.i releases ● Rolling cluster upgrade supported and requires some care
- 72. 72 www.galeracluster.com 4 Happy Clustering :-) Thankyou for listening!