Requêtes de base de données de profil

Lorsque vous écrivez dans une base de données, il peut être utile d’exécuter le profilage pour identifier l’impact de ces modifications. Le profilage conserve un journal des requêtes de la base de données et augmente la précision d’exécution.

Pour activer le profilage des requêtes de base de données:

  1. Connexion à la base de données.

  2. Activez le profilage.

    code language-sql
    SET @@profiling = 1;
    ... run some queries
    
  3. Afficher le journal des requêtes.

    code language-sql
    SHOW profiles
    
  4. Effacez la file d’attente des profils.

    code language-sql
    SET @@profiling = 0;
    SET @@profiling_history_size = 0;
    SET @@profiling_history_size = 100;
    SET @@profiling = 1;
    

Exemple de journal

MariaDB [6fck2obu3244c]> show profiles;
+----------+------------+---------------------------------------------------------------------------------------------------------------------------------+
| Query_ID | Duration   | Query                                                                                                                           |
+----------+------------+---------------------------------------------------------------------------------------------------------------------------------+
|        2 | 0.00375905 | ALTER TABLE mcom_logged_messages_queue DROP INDEX status                                                                        |
|        3 | 1.13660446 | CREATE INDEX `idx_status_direction` ON mcom_logged_messages_queue (status, direction)                                           |
|        4 | 0.00270735 | SELECT count(*) FROM `mcom_logged_messages_queue` WHERE (status = 'FAILED') AND (direction = 'outgoing') ORDER BY `sent_at` ASC |
|        5 | 0.00376312 | ALTER TABLE mcom_logged_messages_queue DROP INDEX status                                                                        |
|        6 | 0.00585975 | ALTER TABLE mcom_logged_messages_queue DROP INDEX idx_status_direction                                                          |
|        7 | 1.16887269 | CREATE INDEX `idx_status` ON mcom_logged_messages_queue (status)                                                                |
|        8 | 0.00299303 | SELECT count(*) FROM `mcom_logged_messages_queue` WHERE (status = 'FAILED') AND (direction = 'outgoing') ORDER BY `sent_at` ASC |
|        9 | 0.00379892 | ALTER TABLE mcom_logged_messages_queue DROP INDEX status                                                                        |
|       10 | 0.00737345 | ALTER TABLE mcom_logged_messages_queue DROP INDEX idx_status                                                                    |
|       11 | 1.05551113 | CREATE INDEX `idx_direction` ON mcom_logged_messages_queue (direction)                                                          |
|       12 | 1.02493811 | SELECT count(*) FROM `mcom_logged_messages_queue` WHERE (status = 'FAILED') AND (direction = 'outgoing') ORDER BY `sent_at` ASC |
|       13 | 0.00368751 | ALTER TABLE mcom_logged_messages_queue DROP INDEX status                                                                        |
|       14 | 0.00706102 | ALTER TABLE mcom_logged_messages_queue DROP INDEX idx_direction                                                                 |
|       15 | 0.29753293 | SELECT count(*) FROM `mcom_logged_messages_queue` WHERE (status = 'FAILED') AND (direction = 'outgoing') ORDER BY `sent_at` ASC |
|       16 | 1.24034449 | CREATE INDEX `idx_direction` ON mcom_logged_messages_queue (direction)                                                          |
|       17 | 0.74422050 | SELECT count(*) FROM `mcom_logged_messages_queue` WHERE (status = 'FAILED') AND (direction = 'outgoing') ORDER BY `sent_at` ASC |
|       18 | 1.16976630 | CREATE INDEX `idx_status` ON mcom_logged_messages_queue (status)                                                                |
|       19 | 0.00293179 | SELECT count(*) FROM `mcom_logged_messages_queue` WHERE (status = 'FAILED') AND (direction = 'outgoing') ORDER BY `sent_at` ASC |
|       20 | 0.02663829 | SELECT * FROM `mcom_logged_messages_queue` WHERE (status = 'FAILED') AND (direction = 'outgoing') ORDER BY `sent_at` ASC        |
|       21 | 0.00736756 | ALTER TABLE mcom_logged_messages_queue DROP INDEX idx_direction                                                                 |
|       22 | 0.00406736 | ALTER TABLE mcom_logged_messages_queue DROP INDEX status                                                                        |
|       23 | 0.00815528 | ALTER TABLE mcom_logged_messages_queue DROP INDEX idx_status                                                                    |
|       24 | 0.37585821 | SELECT * FROM `mcom_logged_messages_queue` WHERE (status = 'FAILED') AND (direction = 'outgoing') ORDER BY `sent_at` ASC        |
+----------+------------+---------------------------------------------------------------------------------------------------------------------------------+
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