This slide was presented at Mydbops Database Meetup 4 by Aakash M . This presentation focuses the new features in Galera like Streaming replication and intelligent donor selection.

1. What’s new in Galera 4 ?
Mydbops Meetup - 4
Presented by
M.Aakash
www.mydbops.com info@mydbops.com 1

2. About me
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Aakash Muthuramalingam
Certified MySQL 5.7 DBA, Mydbops
Interested on MySQL Optimization and High Availability systems.
Active MySQL Blogger.
LinkedIn :
https://www.linkedin.com/in/aakash-muthuramalingam-520a77129
Twitter: https://twitter.com/Aakash_07

3. About Mydbops
● Founded in 2015, HQ in Bangalore India with 150+ customer base across the globe.
● Mydbops is on Database Consulting with core specialization on MySQL and MongoDB Administration and
Support.
● We have expert team with 20+ certified DBA’s providing full time support and currently managing 300+
servers on premises and cloud.
● We help organisations to architect and scale systems in MySQL/MongoDB by implementing the advanced
technologies in industry which are completely open source.
● We are a leading solution provider in the market for all sort of cloud based database deployments and
management.
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4. Mydbops at a GlanceHappy Customers
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5. Agenda
● Galera Replication Overview
● Galera 4 features
● Streaming Replication
● Configuring Streaming Replication
● Rolling Upgrade
● Other features
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6. Galera Replication Overview
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7. Replication in MySQL
● Asynchronous Replication
● Semi-synchronous Replication
● Synchronous Replication
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8. Asynchronous Replication
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9. Semi Synchronous Replication
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10. Synchronous Replication
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11. Galera Replication Overview
● Replication Plugin for database servers
● Using the Replication API to interact with a DBMS.
● Database and Galera plugin must have the same
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12. Galera Replication Overview
Galera Cluster Basic Architecture
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13. Galera Replication Overview
● Read/Write to any node
● Automatic Node Provisioning
● Each node has identical data
● Synchronous Replication
● No Slave Lag
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14. Galera Replication Overview
● Distributions:
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Galera 3 Galera 4
MariaDB 5.5, 10.0, 10.1, 10.2 ,10.3 MariaDB 10.4
Percona XtraDB Cluster 5.5, 5.6, 5.7 Percona XtraDB Cluster 8.0 (In
Development Phase)

15. Features
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16. Galera Features
Galera 3(Existing Features)
● Intelligent Donor Selection
● Cluster Crash Recovery
Galera 4(New Features)
● Huge Transaction Support by Streaming Replication
● New metadata tables
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17. Existing Features
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18. Intelligent Donor Selection
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19. Intelligent Donor Selection
● Intelligent donor choice:
1) Provide IST
2) Within same proximity
3) wsrep_sst_donor
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20. Cluster Crash Recovery
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21. Cluster Crash Recovery
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22. Cluster Crash Recovery
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23. Cluster Crash Recovery
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24. Cluster Crash Recovery
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25. Cluster Crash Recovery
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26. Cluster Crash Recovery
● If all the nodes in the cluster shutdown
1) First node should be elected
2) Manual operation needed
3) Error Prone
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27. Cluster Crash Recovery
● Perform automatic crash recovery
● pc.recovery=on
● Nodes will maintain the information in disk (Persistent storage)
● gvwstate.dat
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28. New Features
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29. Streaming Replication
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30. Streaming Replication
In Galera 3
● Currently transactions processes in master node only until commit
● For huge transactions, the size of write-set will be large
● wsrep_max_ws_size
● wsrep_max_ws_rows
● Maximum supported size is 2GB
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31. Streaming Replication
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T1

32. Streaming Replication
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T1

33. Streaming Replication
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T1

34. Streaming Replication
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T1

35. Streaming Replication
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T1

36. Streaming Replication
In Galera 4
● Transactions are replicated in small fragments in all the nodes during processing
● This allows nodes to process writesets greater than 2GB
● Replicated fragments hold locks in all nodes
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37. Streaming Replication
Configuring Streaming Replication
● wsrep_trx_fragment_unit - bytes/rows/statements
● wsrep_trx_fragment_size - Threshold size
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38. Streaming Replication
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T1
T1(p1)
T1(p1)
T1(p1)

39. Streaming Replication
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T1
T1(p2)
T1(p2)
T1(p2)

40. Streaming Replication
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T1

41. Fragment Applying
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42. Fragment Applying
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43. Fragment Applying
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44. Fragment Applying
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45. Fragment Applying
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46. Fragment Applying
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47. Fragment Applying
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48. New Metadata Tables
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49. New Metadata Tables
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50. New Metadata Tables
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51. New Metadata Tables
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52. New Metadata Tables
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53. Streaming Replication Demo
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54. Node 1 (Galera 3)
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55. Node 2 (Galera 3)
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56. Node 1 (Galera 4)
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57. Node 2 (Galera 4)
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58. Node 2 (Galera 4)
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59. Node 2 (Galera 4)
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60. Rolling Upgrades
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61. Rolling Upgrades
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62. Rolling Upgrades
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63. Rolling Upgrades
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64. Rolling Upgrades
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65. Rolling Upgrades
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66. Rolling Upgrades
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67. Rolling Upgrades
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68. Rolling Upgrades
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69. Rolling Upgrades
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70. Other Features
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71. Other Features
● Non Blocking DDL
● Gcache Encryption
● Cluster Error Voting
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72. Summary
● Replication in MySQL
● Galera Features
● Streaming Replication
● Rolling Upgrades
● Streaming Replication Examples
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73. Queries?
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74. Thank You
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