This document provides an introduction to MySQL InnoDB Cluster, which is MySQL's solution for high availability and scaling. It discusses how Group Replication, the heart of MySQL InnoDB Cluster, allows data to be written simultaneously across cluster nodes while maintaining consistency through techniques like conflict detection and resolution. The document also explains how Group Replication provides automatic recovery from failures and makes high availability easy for users to setup and manage.

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3. ROOUG, December 2017
Introduction to MySQL InnoDB Cluster
MySQL High Availability made easy
Frédéric Descamps - MySQL Community Manager - Oracle
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4.
Safe Harbor Statement
The following is intended to outline our general product direction. It is intended for
information purpose only, and may not be incorporated into any contract. It is not a
commitment to deliver any material, code, or functionality, and should not be relied up in
making purchasing decisions. The development, release and timing of any features or
functionality described for Oracle´s product remains at the sole discretion of Oracle.
Copyright @ 2017 Oracle and/or its affiliates. All rights reserved.
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5. http://about.me/lefred
Who am I ?
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6. Frédéric Descamps
@lefred
MySQL Evangelist
Hacking MySQL since 3.23
devops believer
MySQL Community Manager since May
2016
living in Belgium 🇧🇪
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8. 100%
virtually all organizations require their
most critical systems to be highly
available!
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9.
"High Availability becomes a core first
class feature of MySQL!"
MySQL InnoDB Cluster
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10. MySQL InnoDB Cluster: vision
"A single product - MySQL - with high availability and scaling features baked in;
providing an integrated end-to-end solution that is easy to use."
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11. MySQL InnoDB Cluster: vision
"A single product - MySQL - with high availability and scaling features baked in;
providing an integrated end-to-end solution that is easy to use."
InnoDB
cluster
Ease-of-Use
Extreme Scale-Out
Out-of-Box Solution
Built-in HA
High Performance
Everything Integrated
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12. One Product: MySQL
All components created together
Tested together
Packaged together
Easy to Use
One client: MySQL Shell
Easy packaging
Integrated orchestration
Homogenous servers
Flexible and Modern
SQL and NoSQL together
Protocol Buffers
Asynchronous API
Developer friendly
Support Read/Write Scale Out
Shared clusters
Federated system of N replica sets
supporting cross shard
operations
Each replica set manages a shard
MySQL InnoDB Cluster: goals
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13. Our vision in 4 steps
MySQL Document Store
Relational & Document Models
MySQL HA
Out-Of-Box HA
Read Scale-Out
Async Replication + Auto Failover
Write Scale-Out
Sharding
S1 S3
S2 S4
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14. Step 2´s Architecture
Application
MySQL Connector
MySQL Router
MySQL Shell
InnoDB
cluster
Application
MySQL Connector
MySQL Router
Mp
M
M
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15. Step 3´s Architecture
Application
MySQL Connector
MySQL Router
MySQL Shell
InnoDB
cluster
Application
MySQL Connector
MySQL Router
Mp
M
M
S1 S2 S3 S4 S...
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16. Step 4´s Architecture
Application
MySQL Connector
MySQL Router
MySQL Shell
Application
MySQL Connector
MySQL Router
InnoDB
cluster
Mp
M
M
S2 S3 S4 S...S1
InnoDB
cluster
Mp
M
M
S1 S2 S3 S4 S...
InnoDB
cluster
Mp
M
M
S1 S2 S3 S4 S...
Application
MySQL Connector
MySQL Router
Application
MySQL Connector
MySQL Router
Application
MySQL Connector
MySQL Router
replicaset1
replicaset2
replicaset3
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17. Group Replication: heart of MySQL InnoDB
Cluster
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18. Group Replication: heart of MySQL InnoDB
Cluster
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19. MySQL Group Replication
but what is it ?!?
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20. MySQL Group Replication
but what is it ?!?
GR is a plugin for MySQL, made by MySQL and packaged with MySQL
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21. MySQL Group Replication
but what is it ?!?
GR is a plugin for MySQL, made by MySQL and packaged with MySQL
GR is an implementation of Replicated Database State Machine theory
Copyright @ 2017 Oracle and/or its affiliates. All rights reserved.
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22. MySQL Group Replication
but what is it ?!?
GR is a plugin for MySQL, made by MySQL and packaged with MySQL
GR is an implementation of Replicated Database State Machine theory
GR allows to write on all Group Members (cluster nodes) simultaneously while
retaining consistency
Copyright @ 2017 Oracle and/or its affiliates. All rights reserved.
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23. MySQL Group Replication
but what is it ?!?
GR is a plugin for MySQL, made by MySQL and packaged with MySQL
GR is an implementation of Replicated Database State Machine theory
GR allows to write on all Group Members (cluster nodes) simultaneously while
retaining consistency
GR implements conflict detection and resolution
Copyright @ 2017 Oracle and/or its affiliates. All rights reserved.
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24. MySQL Group Replication
but what is it ?!?
GR is a plugin for MySQL, made by MySQL and packaged with MySQL
GR is an implementation of Replicated Database State Machine theory
GR allows to write on all Group Members (cluster nodes) simultaneously while
retaining consistency
GR implements conflict detection and resolution
GR allows automatic distributed recovery
Copyright @ 2017 Oracle and/or its affiliates. All rights reserved.
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25. MySQL Group Replication
but what is it ?!?
GR is a plugin for MySQL, made by MySQL and packaged with MySQL
GR is an implementation of Replicated Database State Machine theory
GR allows to write on all Group Members (cluster nodes) simultaneously while
retaining consistency
GR implements conflict detection and resolution
GR allows automatic distributed recovery
Supported on all MySQL platforms !!
Linux, Windows, Solaris, OSX, FreeBSD
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26. MySQL Group Communication System (GCS)
MySQL Xcom protocol
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27. MySQL Group Communication System (GCS)
MySQL Xcom protocol
Replicated Database State Machine
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28. MySQL Group Communication System (GCS)
MySQL Xcom protocol
Replicated Database State Machine
Paxos based protocol
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29. MySQL Group Communication System (GCS)
MySQL Xcom protocol
Replicated Database State Machine
Paxos based protocol
its task: deliver messages across the distributed system:
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30. MySQL Group Communication System (GCS)
MySQL Xcom protocol
Replicated Database State Machine
Paxos based protocol
its task: deliver messages across the distributed system:
atomically
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31. MySQL Group Communication System (GCS)
MySQL Xcom protocol
Replicated Database State Machine
Paxos based protocol
its task: deliver messages across the distributed system:
atomically
in Total Order
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32. MySQL Group Communication System (GCS)
MySQL Xcom protocol
Replicated Database State Machine
Paxos based protocol
its task: deliver messages across the distributed system:
atomically
in Total Order
MySQL Group Replication receives the Ordered 'tickets' from this GCS subsystem.
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33. And for users ?
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34. And for users ?
no longer necessary to handle server fail-over manually or with a complicated script
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35. And for users ?
no longer necessary to handle server fail-over manually or with a complicated script
GR provides fault tolerance
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36. And for users ?
no longer necessary to handle server fail-over manually or with a complicated script
GR provides fault tolerance
GR enables update-everywhere setups
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37. And for users ?
no longer necessary to handle server fail-over manually or with a complicated script
GR provides fault tolerance
GR enables update-everywhere setups
GR handles crashes, failures, re-connetcs automatically
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38. And for users ?
no longer necessary to handle server fail-over manually or with a complicated script
GR provides fault tolerance
GR enables update-everywhere setups
GR handles crashes, failures, re-connetcs automatically
Allows an easy setup of a MySQL service high available !
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39. OK, but how does it work ?
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40. OK, but how does it work ?
it´s just ...
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41. OK, but how does it work ?
it´s just ...
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42. OK, but how does it work ?
it´s just ...
... no, in fact the writesets replication is synchronous and then certification and apply of
the changes are local to each nodes and asynchronous.
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43. OK, but how does it work ?
it´s just ...
... no, in fact the writesets replication is synchronous and then certification and apply of
the changes are local to each nodes and asynchronous.
not that easy to understand... right ? As a picture is worth a 1000 words, let´s illustrate
this...
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44. MySQL Group Replication
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45. MySQL Group Replication
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46. MySQL Group Replication
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47. MySQL Group Replication
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48. MySQL Group Replication
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49. MySQL Group Replication
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50. MySQL Group Replication
Copyright @ 2017 Oracle and/or its affiliates. All rights reserved.
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51. MySQL Group Replication
Copyright @ 2017 Oracle and/or its affiliates. All rights reserved.
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52. MySQL Group Replication
Copyright @ 2017 Oracle and/or its affiliates. All rights reserved.
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53. MySQL Group Replication
Copyright @ 2017 Oracle and/or its affiliates. All rights reserved.
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54. MySQL Group Replication
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55. MySQL Group Replication
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56. MySQL Group Replication (full transaction)
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57. MySQL Group Replication (full transaction)
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58. MySQL Group Replication (full transaction)
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59. MySQL Group Replication (full transaction)
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60. MySQL Group Replication (full transaction)
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61. MySQL Group Replication (full transaction)
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62. MySQL Group Replication (full transaction)
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63. MySQL Group Replication (full transaction)
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64. MySQL Group Replication (full transaction)
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65. Group Replication : Total Order Delivery - GTID
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66. Group Replication : Total Order Delivery - GTID
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67. Group Replication : Total Order Delivery - GTID
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68. Group Replication : Total Order Delivery - GTID
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69. Group Replication : Total Order Delivery - GTID
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70. Group Replication : Total Order Delivery - GTID
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71. Group Replication : Total Order Delivery - GTID
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72. Group Replication : Total Order Delivery - GTID
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73. Group Replication : Total Order Delivery - GTID
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74. Group Replication : Total Order Delivery - GTID
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75. Group Replication : Total Order Delivery - GTID
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76. Group Replication : Total Order Delivery - GTID
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77. Group Replication : Total Order Delivery - GTID
Copyright @ 2017 Oracle and/or its affiliates. All rights reserved.
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78. Group Replication : Total Order Delivery - GTID
Copyright @ 2017 Oracle and/or its affiliates. All rights reserved.
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79. Group Replication : Total Order Delivery - GTID
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80. Group Replication : Total Order Delivery - GTID
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81. Group Replication : Total Order Delivery - GTID
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82. Group Replication : Total Order Delivery - GTID
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83. Group Replication : Total Order Delivery - GTID
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84. Group Replication: return commit
Asynchronous Replication:
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85. Group Replication: return from commit (2)
Semi-Sync Replication:
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86. Group Replication: return from commit (3)
Group Replication:
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87. Group Replication : Optimistic Locking
Group Replication uses optimistic locking
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88. Group Replication : Optimistic Locking
Group Replication uses optimistic locking
during a transaction, local (InnoDB) locking happens
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89. Group Replication : Optimistic Locking
Group Replication uses optimistic locking
during a transaction, local (InnoDB) locking happens
optimistically assumes there will be no conflicts across nodes
(no communication between nodes necessary)
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90. Group Replication : Optimistic Locking
Group Replication uses optimistic locking
during a transaction, local (InnoDB) locking happens
optimistically assumes there will be no conflicts across nodes
(no communication between nodes necessary)
cluster-wide conflict resolution happens only at COMMIT, during certification
Copyright @ 2017 Oracle and/or its affiliates. All rights reserved.
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91. Group Replication : Optimistic Locking
Group Replication uses optimistic locking
during a transaction, local (InnoDB) locking happens
optimistically assumes there will be no conflicts across nodes
(no communication between nodes necessary)
cluster-wide conflict resolution happens only at COMMIT, during certification
Let´s first have a look at the traditional locking to compare.
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92. Traditional locking
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93. Traditional locking
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94. Traditional locking
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95. Traditional locking
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96. Traditional locking
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97. Traditional locking
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98. Optimistic Locking
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99. Optimistic Locking
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100. Optimistic Locking
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101. Optimistic Locking
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102. Optimistic Locking
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103. Optimistic Locking
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104. Optimistic Locking
The system returns error 149 as certification failed:
ERROR 1180 (HY000): Got error 149 during COMMIT
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105. Such conflicts happen only when using multi-
primary group !
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106. Certification
Certification is the process that only needs to answer the following unique question:
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107. Certification
Certification is the process that only needs to answer the following unique question:
can the write (transaction) be applied ?
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108. Certification
Certification is the process that only needs to answer the following unique question:
can the write (transaction) be applied ?
based on unapplied earlier transactions
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109. Certification
Certification is the process that only needs to answer the following unique question:
can the write (transaction) be applied ?
based on unapplied earlier transactions
such conflicts must come for other members/nodes
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110. Certification
Certification is the process that only needs to answer the following unique question:
can the write (transaction) be applied ?
based on unapplied earlier transactions
such conflicts must come for other members/nodes
happens on every member/node
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111. Certification
Certification is the process that only needs to answer the following unique question:
can the write (transaction) be applied ?
based on unapplied earlier transactions
such conflicts must come for other members/nodes
happens on every member/node
should be deterministic on every node
Copyright @ 2017 Oracle and/or its affiliates. All rights reserved.
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112. Certification
Certification is the process that only needs to answer the following unique question:
can the write (transaction) be applied ?
based on unapplied earlier transactions
such conflicts must come for other members/nodes
happens on every member/node
should be deterministic on every node
results are not reported to the group
Copyright @ 2017 Oracle and/or its affiliates. All rights reserved.
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113. Certification
Certification is the process that only needs to answer the following unique question:
can the write (transaction) be applied ?
based on unapplied earlier transactions
such conflicts must come for other members/nodes
happens on every member/node
should be deterministic on every node
results are not reported to the group
pass: enter in the apply queue
Copyright @ 2017 Oracle and/or its affiliates. All rights reserved.
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114. Certification
Certification is the process that only needs to answer the following unique question:
can the write (transaction) be applied ?
based on unapplied earlier transactions
such conflicts must come for other members/nodes
happens on every member/node
should be deterministic on every node
results are not reported to the group
pass: enter in the apply queue
fail: drop the transaction
Copyright @ 2017 Oracle and/or its affiliates. All rights reserved.
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115. Certification
Certification is the process that only needs to answer the following unique question:
can the write (transaction) be applied ?
based on unapplied earlier transactions
such conflicts must come for other members/nodes
happens on every member/node
should be deterministic on every node
results are not reported to the group
pass: enter in the apply queue
fail: drop the transaction
serialized by the total order in GCS/XCOM + GTID
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116. Certification
Certification is the process that only needs to answer the following unique question:
can the write (transaction) be applied ?
based on unapplied earlier transactions
such conflicts must come for other members/nodes
happens on every member/node
should be deterministic on every node
results are not reported to the group
pass: enter in the apply queue
fail: drop the transaction
serialized by the total order in GCS/XCOM + GTID
cost is based on trx size (# rows & # keys)
Copyright @ 2017 Oracle and/or its affiliates. All rights reserved.
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117. Certification
Certification is the process that only needs to answer the following unique question:
can the write (transaction) be applied ?
based on unapplied earlier transactions
such conflicts must come for other members/nodes
happens on every member/node
should be deterministic on every node
results are not reported to the group
pass: enter in the apply queue
fail: drop the transaction
serialized by the total order in GCS/XCOM + GTID
cost is based on trx size (# rows & # keys)
first committer (and ack from majority) wins rule
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118. Drawbacks of optimistic locking
having a first-committer-wins system means conflicts will more likely happen when
writing on multiple members with:
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119. Drawbacks of optimistic locking
having a first-committer-wins system means conflicts will more likely happen when
writing on multiple members with:
large transactions
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120. Drawbacks of optimistic locking
having a first-committer-wins system means conflicts will more likely happen when
writing on multiple members with:
large transactions
long running transactions
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121. Drawbacks of optimistic locking
having a first-committer-wins system means conflicts will more likely happen when
writing on multiple members with:
large transactions
long running transactions
hotspot records
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122. Default = Single Primary Mode
By default, MySQL InnoDB Cluster runs in Single Primary Mode.
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123. Default = Single Primary Mode
By default, MySQL InnoDB Cluster runs in Single Primary Mode.
mysql> show global variables like 'group_replication_single_primary_mode';
+---------------------------------------+-------+
| Variable_name | Value |
+---------------------------------------+-------+
| group_replication_single_primary_mode | ON |
+---------------------------------------+-------+
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124. Default = Single Primary Mode
By default, MySQL InnoDB Cluster runs in Single Primary Mode.
mysql> show global variables like 'group_replication_single_primary_mode';
+---------------------------------------+-------+
| Variable_name | Value |
+---------------------------------------+-------+
| group_replication_single_primary_mode | ON |
+---------------------------------------+-------+
In Single Primary Mode, a single member acts as the writable master (PRIMARY) and
the rest of the members act as hot-standbys (SECONDARY).
The group itself coordinates and configures itself automatically to determine which
member will act as the PRIMARY, through a leader election mechanism.
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125. Single Primary Mode - new in 8.0.2
group_replication_member_weight: influence the primary member election in Single-
Primary mode (from 0 to 100).
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126. Single Primary Mode - new in 8.0.2
group_replication_member_weight: influence the primary member election in Single-
Primary mode (from 0 to 100).
more visibility
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127. Single Primary Mode - new in 8.0.2
group_replication_member_weight: influence the primary member election in Single-
Primary mode (from 0 to 100).
more visibility
mysql-sql> select * from performance_schema.replication_group_members;
+--------------+--------------+--------+------+---------+-------------+-------+
| CHANNEL_NAME | MEMBER_ID | M_HOST | PORT | M_STATE | MEMBER_ROLE | M_VER |
+--------------+--------------+--------+------+---------+-------------+-------+
| gr_applier | ...-8d90-... | mysql1 | 3306 | ONLINE | SECONDARY | 8.0.2 |
| gr_applier | ...-be23-... | mysql2 | 3306 | ONLINE | SECONDARY | 8.0.2 |
| gr_applier | ...-a747-... | mysql3 | 3306 | ONLINE | PRIMARY | 8.0.2 |
+--------------+--------------+--------+------+---------+-------------+-------+
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128. New in MySQL 8.0.3
Group Replication flow control variables now correctly permit you to have some
members in a group that do not affect the minimum throughput of the flow-control
mechanism
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129. New in MySQL 8.0.3
Group Replication flow control variables now correctly permit you to have some
members in a group that do not affect the minimum throughput of the flow-control
mechanism
GCS instrumentation in Performance_Schema
thread/group_rpl/THD_Gcs_xcom_control
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130. New in MySQL 8.0.3
Group Replication flow control variables now correctly permit you to have some
members in a group that do not affect the minimum throughput of the flow-control
mechanism
GCS instrumentation in Performance_Schema
thread/group_rpl/THD_Gcs_xcom_control
Auto-setting Read Only when leaving the Group
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131. Copyright @ 2017 Oracle and/or its affiliates. All rights reserved.
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132. MySQL Router (GA!)
MySQL Router is lightweight middleware that provides transparent routing between your
application and backend MySQL Servers. It can be used for a wide variety of use cases,
such as providing high availability and scalability by effectively routing database traffic
to appropriate backend MySQL Servers.
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133. MySQL Router (GA!)
MySQL Router is lightweight middleware that provides transparent routing between your
application and backend MySQL Servers. It can be used for a wide variety of use cases,
such as providing high availability and scalability by effectively routing database traffic
to appropriate backend MySQL Servers.
MySQL Router doesn´t require any specific configuration. It configures itself
automatically (bootstrap) using MySQL InnoDB Cluster´s metadata.
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134. MySQL Router (GA!)
MySQL Router is lightweight middleware that provides transparent routing between your
application and backend MySQL Servers. It can be used for a wide variety of use cases,
such as providing high availability and scalability by effectively routing database traffic
to appropriate backend MySQL Servers.
MySQL Router doesn´t require any specific configuration. It configures itself
automatically (bootstrap) using MySQL InnoDB Cluster´s metadata.
The MySQL Router development will be focusing on sharding.
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135. ProxySQL has native support for Group
Replication which makes it a good choice
for advanced users.
ProxySQL
If you need some specific features that are not yet available in MySQL Router, like
transparent R/W splitting, then you can use your software of choice.
We are also collaborating with ProxySQL.
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136. Copyright @ 2017 Oracle and/or its affiliates. All rights reserved.
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137. MySQL Shell (GA!)
The MySQL Shell is an interactive Javascript, Python, or SQL interface supporting
development and administration for the MySQL Server and is a component of the MySQL
Server. You can use the MySQL Shell to perform data queries and updates as well as
various administration operations.
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138. MySQL Shell (2)
The MySQL Shell provides:
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139. MySQL Shell (2)
The MySQL Shell provides:
Both Interactive and Batch operations
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140. MySQL Shell (2)
The MySQL Shell provides:
Both Interactive and Batch operations
Document and Relational Models
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141. MySQL Shell (2)
The MySQL Shell provides:
Both Interactive and Batch operations
Document and Relational Models
CRUD Document and Relational APIs via scripting
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142. MySQL Shell (2)
The MySQL Shell provides:
Both Interactive and Batch operations
Document and Relational Models
CRUD Document and Relational APIs via scripting
Traditional Table, JSON, Tab Separated output results formats
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143. MySQL Shell (2)
The MySQL Shell provides:
Both Interactive and Batch operations
Document and Relational Models
CRUD Document and Relational APIs via scripting
Traditional Table, JSON, Tab Separated output results formats
MySQL Standard and X Protocols
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144. MySQL Shell (2)
The MySQL Shell provides:
Both Interactive and Batch operations
Document and Relational Models
CRUD Document and Relational APIs via scripting
Traditional Table, JSON, Tab Separated output results formats
MySQL Standard and X Protocols
and more...
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145. don´t forget, this is a HA solution !
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146. Demo ?
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147. Copyright @ 2017 Oracle and/or its affiliates. All rights reserved.
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148. Thank you !
Any Questions ?
more at http://lefred.be/content/category/mysql/group-replication/
http://mysqlhighavailability.com/
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