😂 👨‍⚕️ 😕 Examen de l'utilisation de la mémoire MySQL avec le schéma de performances 🕞 👐🏾 🗝️

Expert OTUS - Vladislav Rodin invite tout le monde à une leçon de démonstration gratuite sur le thème: "Index MySQL: bonnes pratiques et pièges" . La leçon a été préparée spécifiquement pour le "SGBD dans les systèmes à forte charge" super intensif .
Et nous partageons traditionnellement avec vous une traduction utile sur le sujet.

Comprendre comment MySQL utilise la mémoire est essentiel pour régler votre système pour des performances optimales, ainsi que pour dépanner une utilisation anormale de la mémoire, comme lorsque vous avez un serveur MySQL utilisant beaucoup plus de mémoire que vous ne le pensez en fonction paramètres de configuration.

MySQL . , ? , - ? MySQL , , .

MySQL 5.7, Performance Schema, MySQL 8.0 , .

, Sys :

mysql> select event_name,current_alloc from sys.memory_global_by_current_bytes limit 10;
+---------------------------------------------------------------+---------------+
| event_name                                                    | current_alloc |
+---------------------------------------------------------------+---------------+
| memory/innodb/buf_buf_pool                                    | 262.12 MiB    |
| memory/temptable/physical_ram                                 | 64.00 MiB     |
| memory/performance_schema/events_statements_summary_by_digest | 39.67 MiB     |
| memory/sql/TABLE                                              | 33.32 MiB     |
| memory/innodb/ut0link_buf                                     | 24.00 MiB     |
| memory/innodb/lock0lock                                       | 20.51 MiB     |
| memory/innodb/memory                                          | 17.79 MiB     |
| memory/innodb/buf0dblwr                                       | 17.08 MiB     |
| memory/innodb/ut0new                                          | 16.08 MiB     |
| memory/performance_schema/events_statements_history_long      | 13.89 MiB     |
+---------------------------------------------------------------+---------------+
10 rows in set (0.01 sec)

. , , :

mysql> select host,current_allocated from memory_by_host_by_current_bytes;
+-------------------------------+-------------------+
| host                          | current_allocated |
+-------------------------------+-------------------+
| localhost                     | 1.19 GiB          |
| background                    | 101.28 MiB        |
| li1317-164.members.linode.com | 49.61 MiB         |
| li1319-234.members.linode.com | 27.90 MiB         |
| li1316-24.members.linode.com  | 27.00 MiB         |
+-------------------------------+-------------------+
5 rows in set (0.02 sec)

thread_id, , :

mysql> select thread_id,user,current_allocated from memory_by_thread_by_current_bytes limit 5;
+-----------+------------------------------------+-------------------+
| thread_id | user                               | current_allocated |
+-----------+------------------------------------+-------------------+
|        44 | innodb/srv_worker_thread           | 1.99 MiB          |
|        48 | innodb/srv_worker_thread           | 1.16 MiB          |
|     54322 | root@localhost                     | 1.10 MiB          |
|        46 | innodb/srv_worker_thread           | 777.29 KiB        |
|     43881 | app1@li1317-164.members.linode.com | 274.84 KiB        |
+-----------+------------------------------------+-------------------+
5 rows in set (0.43 sec)

, , , . , … Percona Monitoring and Management (PMM).

, PMM 2.11, Performance Schema. (Custom Queries).

MySQL

- , MySQL SQL- , MySQL. Performance Schema, Information Schema , , . Percona Monitoring and Management.

MySQL Performance Schema …

cd /usr/local/percona/pmm2/collectors/custom-queries/mysql/medium-resolution
wget https://raw.githubusercontent.com/Percona-Lab/pmm-custom-queries/master/mysql/ps-memory-summary.yml

MySQL (MySQL Memory Usage Details dashboard) Grafana.com. , , .

-, , , Performance Schema, :