Mastering MySQL Database Architecture: Deep Dive into MySQL Shell and MySQL Router

Mastering MySQL Database Architectures
MySQL Webinar Series
Miguel Araújo
Senior Principal Software Engineer
MySQL, Oracle
April 23, 2024
Deep Dive into MySQL Shell and MySQL Router

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development, release and timing of any features or functionality described for Oracle's product
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Safe Harbor Statement
Copyright © 2024, Oracle and/or its affiliates. All rights reserved.
2

00:00 Business Requirements & MySQL Architectures
00:15 MySQL Shell: AdminAPI & Features
00:25 MySQL Router: Architecture & Features
00:35 Deployment Strategies
00:40 Advanced Features
00:45 Latest Additions
00:50 Q & A
3
~/mysql_webinar
Agenda

4
Business Requirements

Concepts – RTO & RPO
• RTO: Recovery Time Objective
• How long does it take to recover from a single
failure
• RPO: Recovery Point Objective
• How much data can be lost when a failure occurs
Types of Failures
• High Availability:
• Single Server Failure, Network Partition
• Disaster Recovery:
• Full Region / Network failure
• Human Error:
• Little Bobby Tables
5 Copyright © 2024, Oracle and/or its affiliates. All rights reserved.
Business Requirements

6
MySQL Architectures

'classic', 'asynchronous' Replication based
Solution
• Manual failover & switchover
• Asynchronous reads
• Good write performance
MySQL InnoDB ReplicaSet
RPO != 0
RTO = minutes or more (manual failover)

High Availability solution based on Group
Replication
• Automatic failover / Fault Tolerance
• Automatic membership changes
• Network partition handling
• Consistency
MySQL InnoDB Cluster
RPO = 0
RTO = seconds (automatic failover)

Disaster Tolerance Solution for InnoDB
Clusters deployments in alternate
locations
• High Availability (Failure within a Region)
• RPO = 0
• RTO = seconds (automatic failover)
• Disaster Recovery (Region Failure)
• RPO != 0
• RTO = minutes or more (manual failover)
• No write performance impact
MySQL InnoDB ClusterSet

Read Scale-out
• Add any amount of async read replicas to a
Cluster
• Replicate/Failover from
• PRIMARY
• SECONDARIES
• LIST of candidates
Fully supported on
• InnoDB Cluster
• InnoDB ClusterSet
!
New in 8.1.0
MySQL InnoDB Cluster Read Replicas

MySQL InnoDB ClusterSet with Read Replicas
Flexible
• Add/Remove Read Replicas online
• Configure Router behavior dynamically
• Choose where to route traffic
Failover
• Automatic connection failover
• List of potential sources automatic or
manually populated
!
New in 8.1.0

12
What architecture fits my requirements?

Single Region
MySQL InnoDB Cluster
• RPO = 0
• RTO = Seconds
MySQL InnoDB ReplicaSet
• RPO != 0
• RTO = Minutes or more (Manual failover)
High Availability
Best write performance Manual Failover
🔴
🟢
Automatic failover
🟢

Multi Region
High Availability
MySQL InnoDB Cluster: Deployed over multiple regions
Multi-Region Multi-Primary
3 DC
Requires very stable WAN
Write performance affected by latency between DCs
• RPO = 0
• RTO = Seconds
🟢
🔴
🔴
🔴

Multi Region
Disaster Recovery
MySQL InnoDB ClusterSet
RPO = 0 & RTO = seconds within Region (HA)
Write performance (no sync to other region required)
Higher RTO: Manual failover
RPO != 0 when region fails
• RPO != 0
• RTO = Minutes or more
(Manual Failover)
🔴
🔴
🟢
🟢

Read Scale-Out
MySQL InnoDB Cluster Read Replicas
Read Intensive Workloads
Offload Primary or Secondaries
Dedicated instances for other purposes
Additional redundancy for the dataset
🟢
🟢
🟢
🟢

Absolutely...
Complex?

User Requirements
18
Easy to deploy
1

User Requirements
19
Easy to deploy
1 2 Easy to maintain

User Requirements
20
Easy to deploy
1 2 Easy to maintain Easy to monitor
3

21
MySQL Shell AdminAPI

Makes it easy
-----------------------------------------------------------------
Action Command # Calls
-----------------------------------------------------------------
Configure instances dba.configure_replica_set_instance(…) 3
Create Topology dba.create_replica_set(…) 1
Setup Admin Account rs.setup_admin_account(…) 1
Add instances rs.add_instance(…) 2
-----------------------------------------------------------------
SUM: 7
-----------------------------------------------------------------
-
InnoDB ReplicaSet
1
2 3

Makes it easy
-----------------------------------------------------------------
-----------------------------------------------------------------
Configure instances dba.configure_instance(…) 3
Create Topology dba.create_cluster(…) 1
Setup Admin Account c.setup_admin_account(…) 1
Add instances c.add_instance(…) 2
-----------------------------------------------------------------
SUM: 7
-----------------------------------------------------------------
-
InnoDB Cluster
1
2 3

Makes it easy
--------------------------------------------------------
--------------------------------------------------------
Create Topology c.create_cluster_set(…) 1
Create Replica Cluster cs.create_replica_cluster(…) 2
Add instances to Replica rc.add_instance(…) 3
--------------------------------------------------------
SUM: 6
--------------------------------------------------------
InnoDB ClusterSet
1 2
3 4

Makes it easy
-------------------------------------------------------------
-------------------------------------------------------------
Add Read Replicas c.add_replica_instance(…) 3
Configure Router behavior c.set_routing_option(…) 1
-------------------------------------------------------------
SUM: 4
-------------------------------------------------------------
InnoDB Cluster Read Replicas
1 2 3

• Sandbox management
• Configuration checker & applier
• Account management
• MySQL Architectures management
• Integrated provisioning
• Configuration management
• MySQL Router management
• Follows best practices
General Features
AdminAPI

27
MySQL Router

Architecture
Harness
Loader
routing
connection
_pool
Util Libs
metadata_cache http_server F
r
o
n
t
e
n
d
MySQL Shell
...
MySQL
MySQL MySQL

Built-in plugins
routing Routing endpoints logic
destination_status Keep track of the state of the routing destinations
connection_pool Connection pool
metadata_cache Keep track of the MySQL Architectures state / metadata changes
logger Logging utility
syslog Unix based OSes logging: syslog
eventlog Windows OSes logging: eventlog
http_server HTTP server to handle REST API request
http_auth_realm Authentication realm for the http_server
http_auth_backend Authentication backend for the http_server
~/mysql-server/router/src/

Built-in plugins
io Abstraction for IO OS layer
rest_api General REST API handler
rest_metadata_cache Metadata cache REST API handler
rest_router Global Router REST API handler
rest_routing Routing endpoint REST API handler
router_openssl OpenSSL library integration
router_protobuf Protobuf library integration
~/mysql-server/router/src/

31
Router and MySQL Architectures

Core component of MySQL Architectures
Transparent access to Database Architecture
• Transparent client connection routing
• Load balancing
• Application connection failover
• Little to no configuration needed
• Stateless design
• Part of the application stack
• Full integration into MySQL Architectures
• InnoDB Cluster
• InnoDB ReplicaSet
• InnoDB ClusterSet
• InnoDB Cluster Read Replicas
• 3 TCP Ports:
• PRIMARY traffic
• SECONDARY traffic
• RW splitting
!
New in 8.1.0
!
New in 8.2.0

• Needed to route queries to the appropriate backend of the
topology
• Refreshed each [metadata_cache::ttl]
• Default: 0.5 sec
• ClusterSet: 5 sec
Metadata Cache
mysql_innodb_cluster_metadata
metadata_cache
MySQL Shell
GR
MySQL
MySQL Router

• Push notifications sent via X protocol:
• group_replication/membership/quorum_loss
• group_replication/membership/view
• group_replication_status/role_change
• group_replication/status/state_change
• Router keeps an open connection to the X Plugin port waiting
for push notifications
• For every change, if needed, the metadata cache is updated
• Allows reducing drastically the TTL
GR Notifications
mysql_innodb_cluster_metadata
metadata_cache
MySQL Shell
GR
MySQL
MySQL Router

35
Deployment Strategies

It’s possible to use Router without bootstrapping, however…
Manual configuration
[DEFAULT]
...
[routing:primary]
bind_address = localhost
bind_port = 3331
destinations = myserver_xyz:3306
routing_strategy = first-available
[routing:secondaries]
bind_address = localhost
bind_port = 3332
destinations = myserver_foo:3306, myserver_bar:3306
routing_strategy = round-robin-with-fallback
~/testbase/router/my.conf

Auto-configuration for the MySQL Architecture
• Fetches the topology Metadata information from one of the servers
• Stores it in a dynamic file (data/state.json)
• Registers itself in the Metadata schema
• Creates a configuration file ready to be used
• Creates daemon start/stop scripts
Bootstrapping
MySQL Router

Deploying MySQL Router
1. Install MySQL Router
2. Bootstrap
3. Start it!
$ mysqlrouter --bootstrap clusteradmin@brussels:3306
--directory my_router
--account router_admin
--conf-use-gr-notifications
$ my_router/start.sh
~/testbase/router

It’s recommended to deploy Router on the same host as the application and enable GR
notifications. That allows:
• Using sockets instead of TCP/IP
• Decreasing network latency
• Fine-grained account access
• Scaling-out!

It’s recommended to deploy Router on the same host as the application and enable GR
notifications. That allows:
• Using sockets instead of TCP/IP
• Decreasing network latency
• Fine-grained account access
• Scaling-out!
Alternatively, it’s possible to deploy multiple
Routers in multiple machines under a VIP.

41
Advanced Features

• Based on a Connection Pool
• Re-use server-side connections that the client wanted to close,
saving the setup costs of establishing new ones
• Share server-side connections where the client is idling on an
active connection, to reduce the number of open server-side
connections freeing up resources bound to those idle
connections
Connection Sharing and Reuse
MySQL Router

• Configurable with
• connection_sharing (disabled by default)
• connection_sharing_delay (1 by default)
• Seconds to wait before moving an idle connection to the pool
• idle_timeout (5 by default)
• How many seconds to keep a connection in the pool after the client
disconnects
• max_idle_server_connections (disabled by default)
• How many open connections can be kept in the pool after the client
disconnects
Connection Sharing and Reuse
MySQL Router

• Built on top of the HTTP Server plugin
• Follows the OPENAPI 2.0 spec
• Exposes a Swagger file to describe the REST API:
ü Metadata cache config
ü Metadata cache status
ü Metadata cache instances list
ü Router status
ü Routing plugin status
ü Routes config / status / health / destination / connections
ü Routes list
ü Blocked hosts
REST API

$ curl -k -s -u miguel: https://localhost:8443/api/20190715/metadata/bootstrap/config | jq
{
"clusterName": "myCluster",
"timeRefreshInMs": 500,
"groupReplicationId": "1e6598b4-baab-11ee-adc4-d08e7912e4ee",
"nodes": [
{
"hostname": "127.0.0.1",
"port": 3310
},
{
"hostname": "127.0.0.1",
"port": 3320
},
{ "hostname": "127.0.0.1
~

$ curl -k -s -u miguel: https://localhost:8443/api/20190715/routes | jq
{
"items": [
{
"name": "bootstrap_ro”
},
{ "name": "bootstrap_rw”
},
{
"name": "bootstrap_rw_split”
},
{
"name": "bootstrap_x_ro”
},
~

MySQL REST Service
• Fast and powerful way to serve data to client applications via a
HTTPS REST interface
• Implemented as a MySQL Router feature
• Built on the concepts of ORDS, focusing on the strengths of
MySQL
• Focus on MySQL performance
• Focus on MySQL scalability
• Using MySQL/HeatWave as metadata storage
• Auto REST for tables, views, and procedures
• GUI Frontend with MySQL Shell for VSCode
MySQL REST Service (MRS)

50
Latest Additions / MySQL Router

• TLS handshakes are slow
• Cache and resume TLS sessions from:
• Client to Router
• Router to Server
• Saves time and resources by reducing the connection handshake
• Enabled by default
• Client and Server side caches, configurable with:
• _ssl_session_cache_mode: enable/disable
• _ssl_session_cache_size: max number of cached sessions
• _ssl_session_cache_timeout: cache timeout
TLS Session Caching !
New in 8.1.0
MySQL Router

• Motivation:
• 1 port to rule them all
• Up to now, the application had to be aware of the type of
transaction to use either the RW or the RO port
• It’s performant, but limits the usage of Router
• How it works:
• Router classifies each query as read or write automatically
and forwards to the appropriate backend
• It’s also possible to manually or programmatically to specify
the type of query using
• ROUTER SET
• query_attributes
R/W Splitting
!
New in 8.2.0

R/W Splitting
!
New in 8.2.0
mysqlsh-sql> SELECT 1; // SECONDARY
mysqlsh-sql> INSERT INTO tlb VALUES (1) // PRIMARY
mysqlsh-sql> START TRANSACTION READ_ONLY; // SECONDARY
mysqlsh-sql> CREATE TEMPORARY TABLE tbl (id int); // SECONDARY
mysqlsh-sql> SELECT * FROM tbl; // SECONDARY
mysqlsh-sql> COMMIT; // SECONDARY
mysqlsh-sql> query_attributes router.access_mode read_write;
mysqlsh-sql> select @@port; // PRIMARY
~

R/W Splitting
• The query is sent to the PRIMARY if the
access_mode is read_write
• The query is sent to the SECONDARY if the
access_mode is read_only
• If the access_mode is auto, a query is sent to
a SECONDARY if:
• Inside a READ_ONLY transaction, or
• Router attribute for access mode set
(router.access_mode), or
• Outside a transaction, the connection allows
sharing and the statement is a “read-only”
statement
• If none of the above is met, the query is sent
to the PRIMARY

55
Latest Additions / MySQL Shell

Security
• MySQL Communication Stack used by default 8.0.30
• Full TLS/SSL Support 8.0.33
• Encrypt Group Replication and Asynchronous replication channels
• Certificate-based authentication for intra-node communication
• Certificate-based authentication for Admin and Router accounts
• Certificate-based authentication for Read Replicas 8.4.0

Security
Security

Concurrency Control & Atomicity
• Locking mechanism 8.0.33
• Prevent conflicting operations to run concurrently resulting in unexpected outcome
• Supported on the whole API
• Operations rollback
• Avoid leaving the system / instance in a transient state

Router management
• More control over Router configuration
• stats_updates_frequency 8.1.0
• read_only_targets 8.1.0
• all
• read_replicas
• secondaries
• unreachable_quorum_allowed_traffic 8.2.0

Router management

Router management
• List Router Options 8.4.0
• New command: .router_options([options])
• Router exposes all its configuration in the Metadata
• 3 verbosity levels
• Available on:
• <Cluster>
• <ReplicaSet>
• <ClusterSet>

Router management

Router management
3 verbosity levels:
• 0: includes only options that can be changed
from Shell (default)
• 1: Includes all global options and, per Router,
the options that have a different value than the
global
• 2: includes all global and Router options

MySQL Architectures
• InnoDB Cluster Read Replicas 8.1.0
• InnoDB ReplicaSet new commands: 8.3.0
• .rescan()
• .dissolve()
• .describe()
• Support fine-grained replication options 8.2.0
• SOURCE_*, NETWORK_NAMESPACE
• ClusterSet async channel & ReplicaSet

InnoDB Cluster Read Replicas
// Default, follow primary
mysqlsh-py> cluster.add_replica_instance("brussels:3006")
(...)
// Change to follow secondaries
mysqlsh-py> cluster.set_instance:option("brussels:3006", {"replicationSources":
"secondary"})
mysqlsh-py> cluster.rejoin_instance("brussels:3006")
(...)
// Confipyre Router to use only Read Replicas for R/O traffic
mysqlsh-js> cluster.set_routing_option("read_only_targets", "read_replicas"})
(...)
~/mysql_webinar

Deprecations 8.2.0 & Removals 8.4.0
• 5.7 support EOL’d Oct 2023
• dba.configureLocalInstance()
• Cluster.checkInstanceState()
• Command options:
• ipWhitelist
• connectToPrimary
• clearReadOnly
• failoverConsistency
• multiMaster
• groupSeeds
• memberSslMode
• queryMembers
• user/password
• interactive
• waitRecovery
• updateTopologyMode

67
Thank you!
Questions? Join our Slack channel
bit.ly/mysql-slack

68

Mastering MySQL Database Architecture: Deep Dive into MySQL Shell and MySQL Router

Mastering MySQL Database Architecture: Deep Dive into MySQL Shell and MySQL Router

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