HA and clustering solution: ProxySQL as an intelligent ... and clustering solution: ProxySQL as an...

HA and clustering solution:ProxySQL as an intelligent router for

Galera and Group Replication

Rene Cannao

ProxySQL

Rene Cannao

ProxySQL

Introduction

3

A bit about ProxySQL LLC

We provide services to help build, support

as well as improve the performance &

reliability of your Cloud-Based or On-

Premise MySQL infrastructure:

• ProxySQL Development

• Remote Consulting

• ProxySQL Support Services

• ProxySQL Training

We provide services to help build, support

as well as improve the performance &

reliability of your Cloud-Based or On-

Premise MySQL infrastructure:

• ProxySQL Development

• Remote Consulting

• ProxySQL Support Services

• ProxySQL Training

4

A bit about me…

Rene Cannao

• Founder of ProxySQL

• MySQL DBA

Rene Cannao

• Founder of ProxySQL

• MySQL DBA

5

Other sessions

ProxySQL Hand-on

Monday 5th November , 2018 @9:00AM

ProxySQL Adaptive query routing based on GTID tracking

Wednesday 7th November, 2018 @4:30PM

ProxySQL Hand-on

Monday 5th November , 2018 @9:00AM

ProxySQL Adaptive query routing based on GTID tracking

Wednesday 7th November, 2018 @4:30PM

What is ProxySQL?

7

What is ProxySQL

The MySQL data stargateThe MySQL data stargate

8

ProxySQL Architecture Overview

Data gatewayClients connect to ProxySQLRequests are evaluatedActions are performed

9

Some of the most interesting features:● on-the-fly rewrite of queries

● caching reads outside the database server

● connection pooling and multiplexing

● complex query routing and read/write split

● load balancing

● real time statistics

● monitoring

● data masking

● multiple instances on same ports

10

Some of the most interesting features:● high availability and scalability

● seamless failover

● firewall

● query throttling

● query timeout

● query mirroring

● runtime reconfiguration

● scheduler

● support for Galera/PXC and Group Replication

11

Some of the most interesting features:● support for millions of users

● support for tens of thousands of database servers

● native ProxySQL Clustering solution

● support for ClickHouse as a backend

● support for Aurora

● SSL support for frontend

● SSLv1.2

● native Support for Galera

● causal reads using GTID

What is Galera Cluster and Oracle Group Replication?

What is Galera Cluster?

• Multi-master / Active-Active Clustered MySQL Solution

• Synchronous Replication (certification based)

• Multi-threaded Replication

• InnoDB Compliant

• Suitable for LAN, WAN and Cloud Solutions

• IST (incremental) & SST (full) for state transfer

• Auto reconnect mechanism for rejected nodes





• Suitable for LAN, WAN and Cloud Solutions

• IST (incremental) & SST (full) for state transfer

• Auto reconnect mechanism for rejected nodes

What is Oracle Group Replication?


• Single master by default (group_replication_single_primary_mode)




• Suitable for LAN and low latency networks

• State transfer is based on GTID matching


• Single master by default (group_replication_single_primary_mode)




• Suitable for LAN and low latency networks

• State transfer is based on GTID matching

Why ProxySQL?

• Real time monitoring of backends

• Transparent redirect of traffic

• Automatic reconfiguration

• Real time monitoring of backends

• Transparent redirect of traffic

• Automatic reconfiguration

ProxySQL for Galera

Galera Support in ProxySQL

• Historically in ProxySQL v1.x support for Galera is based on “external”

scripts

• An “external” script is configured in the ProxySQL scheduler:

• proxysql_galera_checker.sh is provided as a “ready to use script”

• ProxySQL 2.x provides native support for Galera

• Historically in ProxySQL v1.x support for Galera is based on “external”

scripts

• An “external” script is configured in the ProxySQL scheduler:

• proxysql_galera_checker.sh is provided as a “ready to use script”

• ProxySQL 2.x provides native support for Galera

A quick overview of pre-2.x support

Typically the script is added to the “scheduler” table and loaded to runtime

Admin> select * from scheduler\G

*************************** 1. row ***************************

id: 1

interval_ms: 10000

filename: /var/lib/proxysql/proxysql_galera_checker.sh

arg1: 127.0.0.1

arg2: 6032

arg3: 0

arg4: /var/lib/proxysql/proxysql_galera_checker.log

arg5: NULL

Typically the script is added to the “scheduler” table and loaded to runtime

Admin> select * from scheduler\G

*************************** 1. row ***************************

id: 1

interval_ms: 10000

filename: /var/lib/proxysql/proxysql_galera_checker.sh

arg1: 127.0.0.1

arg2: 6032

arg3: 0

arg4: /var/lib/proxysql/proxysql_galera_checker.log

arg5: NULL


Sample log file during an outage:

### /var/lib/proxysql/proxysql_galera_checker.log

Sat Jul 16 18:42:14 UTC 2016 Check server 10.10.10.11:3306 , status ONLINE , wsrep_local_state 4

ERROR 2003 (HY000): Can't connect to MySQL server on '10.10.10.12' (111)

Sat Jul 16 18:42:14 UTC 2016 Check server 10.10.10.12:3306 , status ONLINE , wsrep_local_state

Sat Jul 16 18:42:14 UTC 2016 Changing server 10.10.10.12:3306 to status OFFLINE_SOFT


Sat Jul 16 18:42:25 UTC 2016 Check server 10.10.10.11:3306 , status ONLINE ,

wsrep_local_state 4


Sat Jul 16 18:42:25 UTC 2016 Check server 10.10.10.12:3306 , status OFFLINE_SOFT ,

wsrep_local_state


Sample log file during an outage:

### /var/lib/proxysql/proxysql_galera_checker.log



Sat Jul 16 18:42:14 UTC 2016 Check server 10.10.10.12:3306 , status ONLINE , wsrep_local_state

Sat Jul 16 18:42:14 UTC 2016 Changing server 10.10.10.12:3306 to status OFFLINE_SOFT


Sat Jul 16 18:42:25 UTC 2016 Check server 10.10.10.11:3306 , status ONLINE ,

wsrep_local_state 4


Sat Jul 16 18:42:25 UTC 2016 Check server 10.10.10.12:3306 , status OFFLINE_SOFT ,

wsrep_local_state



Changes are reflected in the “mysql_servers” and “runtime_mysql_servers” tables:

Admin> SELECT hostgroup_id,hostname,port,status FROM mysql_servers;

+--------------+-------------+------+--------------+

| hostgroup_id | hostname | port | status |

+--------------+-------------+------+--------------+

| 0 | 10.10.10.11 | 3306 | ONLINE |

| 0 | 10.10.10.12 | 3306 | OFFLINE_SOFT |

| 0 | 10.10.10.13 | 3306 | ONLINE |

+--------------+-------------+------+--------------+

Changes are reflected in the “mysql_servers” and “runtime_mysql_servers” tables:


+--------------+-------------+------+--------------+


+--------------+-------------+------+--------------+

| 0 | 10.10.10.11 | 3306 | ONLINE |

| 0 | 10.10.10.12 | 3306 | OFFLINE_SOFT |

| 0 | 10.10.10.13 | 3306 | ONLINE |

+--------------+-------------+------+--------------+


Changes will be reflected in the “mysql_servers” table:


+--------------+-------------+------+--------------+


+--------------+-------------+------+--------------+

| 0 | 10.10.10.11 | 3306 | ONLINE |

| 0 | 10.10.10.12 | 3306 | OFFLINE_SOFT |

| 0 | 10.10.10.13 | 3306 | ONLINE |

+--------------+-------------+------+--------------+

Changes will be reflected in the “mysql_servers” table:


+--------------+-------------+------+--------------+


+--------------+-------------+------+--------------+

| 0 | 10.10.10.11 | 3306 | ONLINE |

| 0 | 10.10.10.12 | 3306 | OFFLINE_SOFT |

| 0 | 10.10.10.13 | 3306 | ONLINE |

+--------------+-------------+------+--------------+

ProxySQL 2.0 Galera Support

• In ProxySQL 2.0 the concept of the regular “mysql_replication_hostgroup” is

extended

• In addition to “reader_hostgroup” and “writer_hostgroup” we also have the

following additional concepts and hostgroup types:

• max_writers

• writer_is_also_reader

• max_transactions_behind

• backup_writer_hostgroup

• offline_hostgroup

• In ProxySQL 2.0 the concept of the regular “mysql_replication_hostgroup” is

extended

• In addition to “reader_hostgroup” and “writer_hostgroup” we also have the

following additional concepts and hostgroup types:

• max_writers





Galera Related Tables

The key Galera tables in ProxySQL Admin are:

+--------------------------------------------+

| galera related tables |

+--------------------------------------------+

| mysql_galera_hostgroups |

| runtime_mysql_galera_hostgroups |

| mysql_server_galera_log |

+--------------------------------------------+

The key Galera tables in ProxySQL Admin are:

+--------------------------------------------+

| galera related tables |

+--------------------------------------------+

| mysql_galera_hostgroups |

| runtime_mysql_galera_hostgroups |

| mysql_server_galera_log |

+--------------------------------------------+

Galera Configuration Table

The key configuration table is “mysql_galera_hostgroups”:

CREATE TABLE mysql_galera_hostgroups (

writer_hostgroup INT CHECK (writer_hostgroup>=0) NOT NULL PRIMARY KEY,

backup_writer_hostgroup INT CHECK (backup_writer_hostgroup>=0 AND

backup_writer_hostgroup<>writer_hostgroup) NOT NULL,

reader_hostgroup INT NOT NULL CHECK (reader_hostgroup<>writer_hostgroup AND

backup_writer_hostgroup<>reader_hostgroup AND reader_hostgroup>0),

offline_hostgroup INT NOT NULL CHECK (offline_hostgroup<>writer_hostgroup AND

offline_hostgroup<>reader_hostgroup AND backup_writer_hostgroup<>offline_hostgroup AND

offline_hostgroup>=0),

active INT CHECK (active IN (0,1)) NOT NULL DEFAULT 1,

max_writers INT NOT NULL CHECK (max_writers >= 0) DEFAULT 1,

writer_is_also_reader INT CHECK (writer_is_also_reader IN (0,1,2)) NOT NULL DEFAULT 0,

max_transactions_behind INT CHECK (max_transactions_behind>=0) NOT NULL DEFAULT 0,

comment VARCHAR

The key configuration table is “mysql_galera_hostgroups”:

CREATE TABLE mysql_galera_hostgroups (

writer_hostgroup INT CHECK (writer_hostgroup>=0) NOT NULL PRIMARY KEY,

backup_writer_hostgroup INT CHECK (backup_writer_hostgroup>=0 AND

backup_writer_hostgroup<>writer_hostgroup) NOT NULL,

reader_hostgroup INT NOT NULL CHECK (reader_hostgroup<>writer_hostgroup AND

backup_writer_hostgroup<>reader_hostgroup AND reader_hostgroup>0),

offline_hostgroup INT NOT NULL CHECK (offline_hostgroup<>writer_hostgroup AND

offline_hostgroup<>reader_hostgroup AND backup_writer_hostgroup<>offline_hostgroup AND

offline_hostgroup>=0),

active INT CHECK (active IN (0,1)) NOT NULL DEFAULT 1,

max_writers INT NOT NULL CHECK (max_writers >= 0) DEFAULT 1,

writer_is_also_reader INT CHECK (writer_is_also_reader IN (0,1,2)) NOT NULL DEFAULT 0,

max_transactions_behind INT CHECK (max_transactions_behind>=0) NOT NULL DEFAULT 0,

comment VARCHAR


• writer_hostgroup

• the hostgroup id that will contain writer nodes (read_only=0)


• when multiple writers are active (read_only=0 on more than 1x node) but max_writers is defined

• all nodes that exceed this value are moved to the backup writer group (standby nodes)

• reader_hostgroup

• the hostgroup id that will contain reader nodes (read_only=1)


• when ProxySQL's monitoring determines a node is offline or not functional it will be moved

to the offline_hostgroup

• writer_hostgroup

• the hostgroup id that will contain writer nodes (read_only=0)


• when multiple writers are active (read_only=0 on more than 1x node) but max_writers is defined

• all nodes that exceed this value are moved to the backup writer group (standby nodes)

• reader_hostgroup

• the hostgroup id that will contain reader nodes (read_only=1)


• when ProxySQL's monitoring determines a node is offline or not functional it will be moved

to the offline_hostgroup


• active• ProxySQL monitors the active hostgroups and makes use only of active hostgroups

• Facilitates standby configurations e.g. switch configuration in case of DC failover

• max_writers

• limits the number of nodes allocated to the writer hostgroup

• controls behaviour of backup_writer_hostgroup


• determines if a node in the writer hostgroup will also belong to the reader hostgroup


• determines the maximum number of writesets behind the node can fall before shunning the node to

prevent stale reads (this is determined by querying the `wsrep_local_recv_queue` galera variable).

• active• ProxySQL monitors the active hostgroups and makes use only of active hostgroups

• Facilitates standby configurations e.g. switch configuration in case of DC failover

• max_writers

• limits the number of nodes allocated to the writer hostgroup

• controls behaviour of backup_writer_hostgroup


• determines if a node in the writer hostgroup will also belong to the reader hostgroup


• determines the maximum number of writesets behind the node can fall before shunning the node to

prevent stale reads (this is determined by querying the `wsrep_local_recv_queue` galera variable).

Galera Related Global Variables

The check timeouts are controlled in the “global_variables” table’s

“xxx_galera_healthcheck_xxx” variables:

ProxySQL Admin> select * from global_variables where variable_name like

'%monitor_galera%';

+-------------------------------------------+----------------+

| variable_name | variable_value |

+-------------------------------------------+----------------+

| mysql-monitor_galera_healthcheck_interval | 5000 |

| mysql-monitor_galera_healthcheck_timeout | 800 |

+-------------------------------------------+----------------+


“xxx_galera_healthcheck_xxx” variables:


'%monitor_galera%';

+-------------------------------------------+----------------+


+-------------------------------------------+----------------+

| mysql-monitor_galera_healthcheck_interval | 5000 |

| mysql-monitor_galera_healthcheck_timeout | 800 |

+-------------------------------------------+----------------+

Galera Global Status/Variables

read_only

wsrep_desync

wsrep_reject_queries

wsrep_sst_donor_rejects_queries

wsrep_local_state

wsrep_local_recv_queue

wsrep_cluster_status

read_only

wsrep_desync

wsrep_reject_queries

wsrep_sst_donor_rejects_queries

wsrep_local_state

wsrep_local_recv_queue

wsrep_cluster_status

How to configure ProxySQL 2.x for Galera

Define the Galera Hostgroups

In this example, we define the following:

writer_hostgroup = 2 reader_hostgroup = 3

offline_hostgroup = 1 backup_writer_hostgroup = 4

max_writers = 1 writer_is_also_reader = 0

active = 1 max_transactions_behind = 100

ProxySQL Admin> INSERT INTO mysql_galera_hostgroups (writer_hostgroup,

backup_writer_hostgroup, reader_hostgroup, offline_hostgroup, active,

max_writers, writer_is_also_reader, max_transactions_behind)

VALUES (2, 4, 3, 1, 1, 1, 0, 100);

In this example, we define the following:

writer_hostgroup = 2 reader_hostgroup = 3

offline_hostgroup = 1 backup_writer_hostgroup = 4

max_writers = 1 writer_is_also_reader = 0

active = 1 max_transactions_behind = 100

ProxySQL Admin> INSERT INTO mysql_galera_hostgroups (writer_hostgroup,

backup_writer_hostgroup, reader_hostgroup, offline_hostgroup, active,

max_writers, writer_is_also_reader, max_transactions_behind)

VALUES (2, 4, 3, 1, 1, 1, 0, 100);

Define the Galera Servers

• Add two servers to “writer_hostgroup = 2”

• 172.16.1.112 (read_only=0)

• 172.16.1.113 (read_only=0)

• Add one server to “reader_hostgroup = 3”

• 172.16.1.114 (read_only=1)

ProxySQL Admin> INSERT INTO mysql_servers (hostgroup_id,

hostname, port, weight) VALUES (2,'172.16.1.112',3306,100),

(2,'172.16.1.113',3306,10), (3,'172.16.1.114',3306,100);

• Add two servers to “writer_hostgroup = 2” • 172.16.1.112 (read_only=0)

• 172.16.1.113 (read_only=0)

• Add one server to “reader_hostgroup = 3”• 172.16.1.114 (read_only=1)

ProxySQL Admin> INSERT INTO mysql_servers (hostgroup_id,

hostname, port, weight) VALUES (2,'172.16.1.112',3306,100),

(2,'172.16.1.113',3306,10), (3,'172.16.1.114',3306,100);

Verify mysql_servers

ProxySQL Admin> select hostgroup_id, hostname, port, status, weight,

max_connections from mysql_servers;

+--------------+--------------+------+--------+--------+-----------------+

| hostgroup_id | hostname | port | status | weight | max_connections |

+--------------+--------------+------+--------+--------+-----------------+

| 2 | 172.16.1.112 | 3306 | ONLINE | 100 | 1000 |

| 2 | 172.16.1.113 | 3306 | ONLINE | 10 | 1000 |

| 3 | 172.16.1.114 | 3306 | ONLINE | 100 | 1000 |

+--------------+--------------+------+--------+--------+-----------------+

ProxySQL Admin> select hostgroup_id, hostname, port, status, weight,

max_connections from mysql_servers;

+--------------+--------------+------+--------+--------+-----------------+

| hostgroup_id | hostname | port | status | weight | max_connections |

+--------------+--------------+------+--------+--------+-----------------+

| 2 | 172.16.1.112 | 3306 | ONLINE | 100 | 1000 |

| 2 | 172.16.1.113 | 3306 | ONLINE | 10 | 1000 |

| 3 | 172.16.1.114 | 3306 | ONLINE | 100 | 1000 |

+--------------+--------------+------+--------+--------+-----------------+

Verify mysql_galera_hostgroups

ProxySQL Admin> select * from mysql_galera_hostgroups\G

*************************** 1. row ***************************

writer_hostgroup: 2

backup_writer_hostgroup: 4

reader_hostgroup: 3

offline_hostgroup: 1

active: 1

max_writers: 1

writer_is_also_reader: 0

max_transactions_behind: 100

comment: NULL

ProxySQL Admin> select * from mysql_galera_hostgroups\G

*************************** 1. row ***************************

writer_hostgroup: 2

backup_writer_hostgroup: 4

reader_hostgroup: 3

offline_hostgroup: 1

active: 1

max_writers: 1

writer_is_also_reader: 0

max_transactions_behind: 100

comment: NULL

Load / Save Configuration

• We must not forget to “load the configuration to runtime” and additionally “save the configuration to disk”:

# The following command will LOAD both mysql_servers and mysql_galera_hostgroups to RUNTIME making this the active ProxySQL configuration for runtime only (does not persist across restarts):

LOAD MYSQL SERVERS TO RUNTIME;

# The following command will SAVE both mysql_servers and mysql_galera_hostgroups to DISK making this the “persisted” configuration in case ProxySQL is restarted:

SAVE MYSQL SERVERS TO DISK;

• We must not forget to “load the configuration to runtime” and additionally “save the configuration to disk”:

# The following command will LOAD both mysql_servers and mysql_galera_hostgroups to RUNTIME making this the active ProxySQL configuration for runtime only (does not persist across restarts):

LOAD MYSQL SERVERS TO RUNTIME;

# The following command will SAVE both mysql_servers and mysql_galera_hostgroups to DISK making this the “persisted” configuration in case ProxySQL is restarted:

SAVE MYSQL SERVERS TO DISK;

Dynamic Reconfiguration

• After loading the configuration to runtime ProxySQL has reconfigured the “mysql_servers” based on the configuration of “mysql_galera_hostgroups” (specifically due to the configuration “max_writers = 1”)

• The host “172.16.1.113” was moved to the backup_writer_hostgroup

ProxySQL Admin> select hostgroup, srv_host, status, ConnUsed, MaxConnUsed, Queries from stats.stats_mysql_connection_pool order by srv_host;

+-----------+--------------+--------+----------+-------------+-----------+| hostgroup | srv_host | status | ConnUsed | MaxConnUsed | Queries |+-----------+--------------+--------+----------+-------------+-----------+| 2 | 172.16.1.112 | ONLINE | 3 | 4 | 930742390 || 4 | 172.16.1.113 | ONLINE | 0 | 0 | 0 || 3 | 172.16.1.114 | ONLINE | 1 | 1 | 233130345 |+-----------+--------------+--------+----------+-------------+-----------+

• After loading the configuration to runtime ProxySQL has reconfigured the “mysql_servers” based on the configuration of “mysql_galera_hostgroups” (specifically due to the configuration “max_writers = 1”)

• The host “172.16.1.113” was moved to the backup_writer_hostgroup

ProxySQL Admin> select hostgroup, srv_host, status, ConnUsed, MaxConnUsed, Queries from stats.stats_mysql_connection_pool order by srv_host;

+-----------+--------------+--------+----------+-------------+-----------+| hostgroup | srv_host | status | ConnUsed | MaxConnUsed | Queries |+-----------+--------------+--------+----------+-------------+-----------+| 2 | 172.16.1.112 | ONLINE | 3 | 4 | 930742390 || 4 | 172.16.1.113 | ONLINE | 0 | 0 | 0 || 3 | 172.16.1.114 | ONLINE | 1 | 1 | 233130345 |+-----------+--------------+--------+----------+-------------+-----------+

Galera Monitoring Statistics

The statistics related to the Galera cluster can be viewed in the “monitor.mysql_server_galera_log” table:

ProxySQL Admin> select * from mysql_server_galera_log order by time_start_us desc limit 3;*************************** 1. row *************************** hostname: 172.16.1.112 port: 3306 time_start_us: 1529510693289001 success_time_us: 1234 primary_partition: YES read_only: NO wsrep_local_recv_queue: 0 wsrep_local_state: 4 wsrep_desync: NO wsrep_reject_queries: NOwsrep_sst_donor_rejects_queries: NO error: NULL*************************** 2. row *************************** hostname: 172.16.1.113...

The statistics related to the Galera cluster can be viewed in the “monitor.mysql_server_galera_log” table:

ProxySQL Admin> select * from mysql_server_galera_log order by time_start_us desc limit 3;*************************** 1. row *************************** hostname: 172.16.1.112 port: 3306 time_start_us: 1529510693289001 success_time_us: 1234 primary_partition: YES read_only: NO wsrep_local_recv_queue: 0 wsrep_local_state: 4 wsrep_desync: NO wsrep_reject_queries: NOwsrep_sst_donor_rejects_queries: NO error: NULL*************************** 2. row *************************** hostname: 172.16.1.113...

ProxySQL for InnoDB Cluster / Oracle Group Replication (OGR)

OGR Support in ProxySQL

• ProxySQL has had support for OGR since version 1.3.x

• Native support has been available since version 1.4.x

• Configuration of ProxySQL for OGR is very similar to the configuration for

Galera

• The differences are highlighted in the next slides:

• The “max_transactions_behind” variable

• The OGR healthcheck global variables

• A set of stored procedures required for OGR to support ProxySQL

• ProxySQL has had support for OGR since version 1.3.x

• Native support has been available since version 1.4.x

• Configuration of ProxySQL for OGR is very similar to the configuration for

Galera

• The differences are highlighted in the next slides:

• The “max_transactions_behind” variable

• The OGR healthcheck global variables

• A set of stored procedures required for OGR to support ProxySQL

OGR Related Tables

The key OGR tables in ProxySQL Admin are:

+---------------------------------------------+

| ogr related tables. |

+---------------------------------------------+

| mysql_group_replication_hostgroups |

| runtime_mysql_group_replication_hostgroups |

| mysql_server_group_replication_log |

+---------------------------------------------+

The key OGR tables in ProxySQL Admin are:

+---------------------------------------------+

| ogr related tables. |

+---------------------------------------------+

| mysql_group_replication_hostgroups |

| runtime_mysql_group_replication_hostgroups |

| mysql_server_group_replication_log |

+---------------------------------------------+

OGR Configuration Table

The key configuration table is “mysql_group_replication_hostgroups”:

CREATE TABLE mysql_group_replication_hostgroups ( writer_hostgroup INT CHECK (writer_hostgroup>=0) NOT NULL PRIMARY KEY, backup_writer_hostgroup INT CHECK (backup_writer_hostgroup>=0 AND backup_writer_hostgroup<>writer_hostgroup) NOT NULL, reader_hostgroup INT NOT NULL CHECK (reader_hostgroup<>writer_hostgroup AND backup_writer_hostgroup<>reader_hostgroup AND reader_hostgroup>0), offline_hostgroup INT NOT NULL CHECK (offline_hostgroup<>writer_hostgroup AND offline_hostgroup<>reader_hostgroup AND backup_writer_hostgroup<>offline_hostgroup AND offline_hostgroup>=0), active INT CHECK (active IN (0,1)) NOT NULL DEFAULT 1, max_writers INT NOT NULL CHECK (max_writers >= 0) DEFAULT 1, writer_is_also_reader INT CHECK (writer_is_also_reader IN (0,1)) NOT NULL DEFAULT 0, max_transactions_behind INT CHECK (max_transactions_behind>=0) NOT NULL DEFAULT 0, comment VARCHAR, UNIQUE (reader_hostgroup), UNIQUE (offline_hostgroup), UNIQUE (backup_writer_hostgroup))

The key configuration table is “mysql_group_replication_hostgroups”:

CREATE TABLE mysql_group_replication_hostgroups ( writer_hostgroup INT CHECK (writer_hostgroup>=0) NOT NULL PRIMARY KEY, backup_writer_hostgroup INT CHECK (backup_writer_hostgroup>=0 AND backup_writer_hostgroup<>writer_hostgroup) NOT NULL, reader_hostgroup INT NOT NULL CHECK (reader_hostgroup<>writer_hostgroup AND backup_writer_hostgroup<>reader_hostgroup AND reader_hostgroup>0), offline_hostgroup INT NOT NULL CHECK (offline_hostgroup<>writer_hostgroup AND offline_hostgroup<>reader_hostgroup AND backup_writer_hostgroup<>offline_hostgroup AND offline_hostgroup>=0), active INT CHECK (active IN (0,1)) NOT NULL DEFAULT 1, max_writers INT NOT NULL CHECK (max_writers >= 0) DEFAULT 1, writer_is_also_reader INT CHECK (writer_is_also_reader IN (0,1)) NOT NULL DEFAULT 0, max_transactions_behind INT CHECK (max_transactions_behind>=0) NOT NULL DEFAULT 0, comment VARCHAR, UNIQUE (reader_hostgroup), UNIQUE (offline_hostgroup), UNIQUE (backup_writer_hostgroup))

OGR Configuration Table

• The only difference when compared to the Galera Configuration Table is the

concept of “max_transactions_behind”:


• determines the maximum number of binlog events behind the node can fall before shunning the

node to prevent stale reads

• this is determined by querying the sys.gr_member_routing_candidate_status view

• When dealing with OGR this relates to the number of GTID events rather than

Galera writesets

• Apart from this difference the definition of the other fields remains the same as

for the configuration of Galera

• The only difference when compared to the Galera Configuration Table is the

concept of “max_transactions_behind”:


• determines the maximum number of binlog events behind the node can fall before shunning the

node to prevent stale reads

• this is determined by querying the sys.gr_member_routing_candidate_status view

• When dealing with OGR this relates to the number of GTID events rather than

Galera writesets

• Apart from this difference the definition of the other fields remains the same as

for the configuration of Galera

OGR Related Global Variables


“xxx_groupreplication_healthcheck_xxx” variables:


'%monitor_groupreplication%';

+-----------------------------------------------------+----------------+


+-----------------------------------------------------+----------------+

| mysql-monitor_groupreplication_healthcheck_interval | 5000 |

| mysql-monitor_groupreplication_healthcheck_timeout | 800 |

+-----------------------------------------------------+----------------+


“xxx_groupreplication_healthcheck_xxx” variables:


'%monitor_groupreplication%';

+-----------------------------------------------------+----------------+


+-----------------------------------------------------+----------------+

| mysql-monitor_groupreplication_healthcheck_interval | 5000 |

| mysql-monitor_groupreplication_healthcheck_timeout | 800 |

+-----------------------------------------------------+----------------+

OGR Required Stored Procs

The following view and helper functions also need to be added to MySQL in order

for OGR to be compatible with ProxySQL’s monitoring:

• CREATE VIEW gr_member_routing_candidate_status• CREATE FUNCTION gr_member_in_primary_partition

• CREATE FUNCTION gr_applier_queue_length

• CREATE FUNCTION GTID_COUNT

• CREATE FUNCTION GTID_NORMALIZE

• CREATE FUNCTION LOCATE2

• CREATE FUNCTION IFZERO

*** Available here - https://gist.github.com/lefred/77ddbde301c72535381ae7af9f968322

The following view and helper functions also need to be added to MySQL in order

for OGR to be compatible with ProxySQL’s monitoring:

• CREATE VIEW gr_member_routing_candidate_status• CREATE FUNCTION gr_member_in_primary_partition

• CREATE FUNCTION gr_applier_queue_length

• CREATE FUNCTION GTID_COUNT

• CREATE FUNCTION GTID_NORMALIZE

• CREATE FUNCTION LOCATE2

• CREATE FUNCTION IFZERO

*** Available here - https://gist.github.com/lefred/77ddbde301c72535381ae7af9f968322

OGR Required Stored Procs

Once deployed ProxySQL will query the view in order to retrieve the status of each of the OGR nodes (the view can also be used for troubleshooting purposes):

## Status of the primary node (mysql_node1)mysql> SELECT * FROM sys.gr_member_routing_candidate_status;+------------------+-----------+---------------------+----------------------+| viable_candidate | read_only | transactions_behind | transactions_to_cert |+------------------+-----------+---------------------+----------------------+| YES | NO | 0 | 0 |+------------------+-----------+---------------------+----------------------+

## Status of a secondary node (mysql_node2)mysql> SELECT * FROM sys.gr_member_routing_candidate_status;+------------------+-----------+---------------------+----------------------+| viable_candidate | read_only | transactions_behind | transactions_to_cert |+------------------+-----------+---------------------+----------------------+| YES | YES | 0 | 0 |+------------------+-----------+---------------------+----------------------+

Once deployed ProxySQL will query the view in order to retrieve the status of each of the OGR nodes (the view can also be used for troubleshooting purposes):

## Status of the primary node (mysql_node1)mysql> SELECT * FROM sys.gr_member_routing_candidate_status;+------------------+-----------+---------------------+----------------------+| viable_candidate | read_only | transactions_behind | transactions_to_cert |+------------------+-----------+---------------------+----------------------+| YES | NO | 0 | 0 |+------------------+-----------+---------------------+----------------------+

## Status of a secondary node (mysql_node2)mysql> SELECT * FROM sys.gr_member_routing_candidate_status;+------------------+-----------+---------------------+----------------------+| viable_candidate | read_only | transactions_behind | transactions_to_cert |+------------------+-----------+---------------------+----------------------+| YES | YES | 0 | 0 |+------------------+-----------+---------------------+----------------------+

OGR Monitoring Statistics

The statistics related to the OGR cluster can be viewed in the “monitor.mysql_server_group_replication_log” table:

ProxySQL Admin> select * from mysql_server_group_replication_log order by time_start_us desc limit 3\G*************************** 1. row *************************** hostname: mysql_node1 port: 3306 time_start_us: 1515079109821971 success_time_us: 1582 viable_candidate: YES read_only: NOtransactions_behind: 0 error: NULL*************************** 2. row *************************** hostname: mysql_node2 port: 3306 time_start_us: 1515079109822292 success_time_us: 1845 viable_candidate: YES read_only: YEStransactions_behind: 0 error: NULL...

The statistics related to the OGR cluster can be viewed in the “monitor.mysql_server_group_replication_log” table:

ProxySQL Admin> select * from mysql_server_group_replication_log order by time_start_us desc limit 3\G*************************** 1. row *************************** hostname: mysql_node1 port: 3306 time_start_us: 1515079109821971 success_time_us: 1582 viable_candidate: YES read_only: NOtransactions_behind: 0 error: NULL*************************** 2. row *************************** hostname: mysql_node2 port: 3306 time_start_us: 1515079109822292 success_time_us: 1845 viable_candidate: YES read_only: YEStransactions_behind: 0 error: NULL...

OGR Live Demonstration

OGR Live Demo Configuration

• 1x ProxySQL 2.0 instance

• Proxysql1

• 3x MySQL 5.7 Docker Instances

• Mysql1: Read / Write Master

• Mysql2: Read Only Slave


• 1x ProxySQL 2.0 instance

• Proxysql1

• 3x MySQL 5.7 Docker Instances

• Mysql1: Read / Write Master



Thank you!

• Please remember to report feature requests and bug reports:

https://github.com/sysown/proxysql/

• Community support can be found on our forum:

https://groups.google.com/forum/#!forum/proxysql

• Useful blog articles are available at our site: http://proxysql.com/blog

• Visit us at http://proxysql.com/support for subscription and support options

• Please remember to report feature requests and bug reports:

https://github.com/sysown/proxysql/

• Community support can be found on our forum:

https://groups.google.com/forum/#!forum/proxysql

• Useful blog articles are available at our site: http://proxysql.com/blog

• Visit us at http://proxysql.com/support for subscription and support options

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