DatabaseEventSubscriber.php

<?php

namespace Drupal\database_test\EventSubscriber;

use Drupal\Core\Database\Event\StatementExecutionEndEvent;
use Drupal\Core\Database\Event\StatementExecutionFailureEvent;
use Drupal\Core\Database\Event\StatementExecutionStartEvent;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;

/**
 * Responds to database API events.
 */
class DatabaseEventSubscriber implements EventSubscriberInterface {
    
    /**
     * A counter of started statement executions.
     */
    public int $countStatementStarts = 0;
    
    /**
     * A counter of finished statement executions.
     */
    public int $countStatementEnds = 0;
    
    /**
     * A counter of failed statement executions.
     */
    public int $countStatementFailures = 0;
    
    /**
     * A map of statements being executed.
     */
    public array $statementIdsInExecution = [];
    
    /**
     * {@inheritdoc}
     */
    public static function getSubscribedEvents() : array {
        return [
            StatementExecutionStartEvent::class => 'onStatementExecutionStart',
            StatementExecutionEndEvent::class => 'onStatementExecutionEnd',
            StatementExecutionFailureEvent::class => 'onStatementExecutionFailure',
        ];
    }
    
    /**
     * Subscribes to a statement execution started event.
     *
     * @param \Drupal\Core\Database\Event\StatementExecutionStartEvent $event
     *   The database event.
     */
    public function onStatementExecutionStart(StatementExecutionStartEvent $event) : void {
        $this->statementIdsInExecution[$event->statementObjectId] = TRUE;
        $this->countStatementStarts++;
    }
    
    /**
     * Subscribes to a statement execution finished event.
     *
     * @param \Drupal\Core\Database\Event\StatementExecutionEndEvent $event
     *   The database event.
     */
    public function onStatementExecutionEnd(StatementExecutionEndEvent $event) : void {
        unset($this->statementIdsInExecution[$event->statementObjectId]);
        $this->countStatementEnds++;
    }
    
    /**
     * Subscribes to a statement execution failure event.
     *
     * @param \Drupal\Core\Database\Event\StatementExecutionFailureEvent $event
     *   The database event.
     */
    public function onStatementExecutionFailure(StatementExecutionFailureEvent $event) : void {
        unset($this->statementIdsInExecution[$event->statementObjectId]);
        $this->countStatementFailures++;
    }

}