2020 MariaDB Galera Cluster Training Hamburg (Remote)

Read-Write-Split

https://www.percona.com/blog/2016/03/29/read-write-split-routing-performance-in-maxscale/

Monitoring

https://galeracluster.com/library/documentation/monitoring-cluster.html

maxscale

When a server that readwritesplit uses is put into maintenance mode, any ongoing requests are allowed to finish before the connection is closed

Use performance schema for slow queries

performance_schema needs to be on:

`` MariaDB [performance_schema]> show variables like '%perf%schema'; +--------------------+-------+ | Variable_name | Value | +--------------------+-------+ | performance_schema | ON | +--------------------+-------+ 1 row in set (0.001 sec)

MariaDB [performance_schema]>

``

This needs to be set:

MariaDB [performance_schema]> select * from setup_consumers where name like 'stat%' or name like '%instru%'; +------------------------+---------+ | NAME | ENABLED | +------------------------+---------+ | global_instrumentation | YES | | thread_instrumentation | YES | | statements_digest | YES | +------------------------+---------+ 3 rows in set (0.001 sec)

Get all queries by time

MariaDB [performance_schema]> SELECT SCHEMA_NAME, digest, digest_text, round(sum_timer_wait/ 1000000000000, 6), count_star FROM performance_schema.events_statements_summary_by_digest ORDER BY sum_timer_wait DESC LIMIT 10;