Contrib.social

ReplicaKillSwitch unnecessarily starts a session on each request

Open on Drupal.org →
Created on 11 November 2020, about 4 years ago
Updated 19 October 2023, about 1 year ago

Problem/Motivation

Whenever a request is processed, the database.replica_kill_switch service checks if the replica database should be ignored. The problem is that the event subscriber method \Drupal\Core\Database\ReplicaKillSwitch::checkReplicaServer always fetches data from the session, which can cause a session to be started when it has already been stopped.

    if ($this->session->has('ignore_replica_server')) {
      if ($this->session->get('ignore_replica_server') >= $this->time->getRequestTime()) {
        Database::ignoreTarget('default', 'replica');
      }
      else {
        $this->session->remove('ignore_replica_server');
      }
    }

The \Drupal\Core\Database\ReplicaKillSwitch::trigger has a preflight check that sees if a replica server even exists before setting a session variable. The check method should perform this check as well.

Steps to reproduce

On kernel.terminate perform a subrequest. The request triggers the replica killswitch check and throws an except due to headers already being sent.

Proposed resolution

Add this check before reaching into the session service and lazy loading/starting a service

    $connection_info = Database::getConnectionInfo();
    // Only set ignore_replica_server if there are replica servers being used,
    // which is assumed if there are more than one.
    if (count($connection_info) > 1) {

Remaining tasks

User interface changes

API changes

Data model changes

Release notes snippet

🐛 Bug report
Status

Needs work

Version

11.0 🔥

Component
Database  →

Last updated about 4 hours ago

  • Maintained by
  • 🇳🇱Netherlands @daffie
Created by

🇺🇸United States mglaman WI, USA

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  • Comment almost 2 years ago →
    needs-review-queue-bot

    The Needs Review Queue Bot → tested this issue. It either no longer applies to Drupal core, or fails the Drupal core commit checks. Therefore, this issue status is now "Needs work".

    Apart from a re-roll or rebase, this issue may need more work to address feedback in the issue or MR comments. To progress an issue, incorporate this feedback as part of the process of updating the issue. This helps other contributors to know what is outstanding.

    Consult the Drupal Contributor Guide → to find step-by-step guides for working with issues.

  • Status changed to Needs review about 1 year ago
  • Open in Jenkins → Open on Drupal.org →
    Environment: PHP 8.2 & MySQL 8
    last update about 1 year ago
    Patch Failed to Apply
  • Comment about 1 year ago →
    🇨🇦Canada joelpittet Vancouver

    D10 Fails on this patch with

    TypeError: Drupal\Core\Database\ReplicaKillSwitchRequest::__construct(): Argument #1 ($requestStack) must be of type Drupal\Core\Http\RequestStack, Symfony\Component\HttpFoundation\RequestStack given, called in /var/www/html/public/core/lib/Drupal/Component/DependencyInjection/Container.php on line 259 in Drupal\Core\Database\ReplicaKillSwitchRequest->__construct() (line 26 of core/lib/Drupal/Core/Database/ReplicaKillSwitchRequest.php).

    This patch should work for D11 as well.

  • Open in Jenkins → Open on Drupal.org →
    Environment: PHP 8.2 & MySQL 8
    last update about 1 year ago
    30,151 pass
  • Comment about 1 year ago →
    🇦🇺Australia kim.pepper 🏄‍♂️🇦🇺Sydney, Australia

    Fixes the patch conflicts and adds a kernel test.

    I think we need to work out how this would be used instead of the session version? Do we switch to it and deprecate? How do we support both?

  • Open in Jenkins → Open on Drupal.org →
    Environment: PHP 8.1 & MySQL 5.7
    last update about 1 year ago
    Custom Commands Failed
  • Open in Jenkins → Open on Drupal.org →
    Environment: PHP 8.1 & MySQL 5.7
    last update about 1 year ago
    Patch Failed to Apply
  • Comment about 1 year ago →
    🇺🇸United States smustgrave

    Is there any BC concerns if we switch?

  • Status changed to Needs work about 1 year ago
  • Comment about 1 year ago →
    🇺🇸United States smustgrave

    Moving to NW for issue summary update. And if there is a backwards compatibility concern to switch?

  • Open in Jenkins → Open on Drupal.org →
    Environment: PHP 8.1 & MySQL 8
    last update 10 months ago
    Patch Failed to Apply
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