From 7daa126d1ddb39f114f3989ba2896540f0471e36 Mon Sep 17 00:00:00 2001
From: Mark Nelson <mdjnelson@gmail.com>
Date: Mon, 20 Apr 2020 14:35:57 +0200
Subject: [PATCH] MDL-58018 core: add support to database for read-only
 sessions

---
 lib/classes/session/database.php | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/lib/classes/session/database.php b/lib/classes/session/database.php
index ab19a781797..c8c842fcf7b 100644
--- a/lib/classes/session/database.php
+++ b/lib/classes/session/database.php
@@ -172,7 +172,9 @@ class database extends handler {
             }
             if (!$this->recordid) {
                 // Lock session if exists and not already locked.
-                $this->database->get_session_lock($record->id, $this->acquiretimeout);
+                if ($this->requires_write_lock()) {
+                    $this->database->get_session_lock($record->id, $this->acquiretimeout);
+                }
                 $this->recordid = $record->id;
             }
         } catch (\dml_sessionwait_exception $ex) {