diff --git a/core/lib/Drupal/Core/Database/Log.php b/core/lib/Drupal/Core/Database/Log.php
index f7f0286da9..5fe27ec5dc 100644
--- a/core/lib/Drupal/Core/Database/Log.php
+++ b/core/lib/Drupal/Core/Database/Log.php
@@ -108,9 +108,13 @@ public function end($logging_key) {
    * @param $args
    *   The arguments passed to the statement object.
    * @param $time
-   *   The time in milliseconds the query took to execute.
+   *   The time the query took to execute as a float (in seconds with
+   *   microsecond precision).
+   * @param $start
+   *   The time the query started as a float (in seconds since the Unix epoch
+   *   with microsecond precision).
    */
-  public function log(StatementInterface $statement, $args, $time) {
+  public function log(StatementInterface $statement, $args, $time, $start = NULL) {
     foreach (array_keys($this->queryLog) as $key) {
       $this->queryLog[$key][] = [
         'query' => $statement->getQueryString(),
@@ -118,6 +122,7 @@ public function log(StatementInterface $statement, $args, $time) {
         'target' => $statement->dbh->getTarget(),
         'caller' => $this->findCaller(),
         'time' => $time,
+        'start' => $start,
       ];
     }
   }
diff --git a/core/lib/Drupal/Core/Database/Statement.php b/core/lib/Drupal/Core/Database/Statement.php
index 3de4537fb2..7a52c35cee 100644
--- a/core/lib/Drupal/Core/Database/Statement.php
+++ b/core/lib/Drupal/Core/Database/Statement.php
@@ -68,7 +68,7 @@ public function execute($args = [], $options = []) {
 
     if (!empty($logger)) {
       $query_end = microtime(TRUE);
-      $logger->log($this, $args, $query_end - $query_start);
+      $logger->log($this, $args, $query_end - $query_start, $query_start);
     }
 
     return $return;
diff --git a/core/lib/Drupal/Core/Database/StatementPrefetch.php b/core/lib/Drupal/Core/Database/StatementPrefetch.php
index 3f6efdf364..b7a8fd22b2 100644
--- a/core/lib/Drupal/Core/Database/StatementPrefetch.php
+++ b/core/lib/Drupal/Core/Database/StatementPrefetch.php
@@ -186,7 +186,7 @@ public function execute($args = [], $options = []) {
 
     if (!empty($logger)) {
       $query_end = microtime(TRUE);
-      $logger->log($this, $args, $query_end - $query_start);
+      $logger->log($this, $args, $query_end - $query_start, $query_start);
     }
 
     // Initialize the first row in $this->currentRow.
diff --git a/core/lib/Drupal/Core/Database/StatementWrapper.php b/core/lib/Drupal/Core/Database/StatementWrapper.php
index eff40102f4..dcc074604c 100644
--- a/core/lib/Drupal/Core/Database/StatementWrapper.php
+++ b/core/lib/Drupal/Core/Database/StatementWrapper.php
@@ -117,7 +117,7 @@ public function execute($args = [], $options = []) {
 
     if (!empty($logger)) {
       $query_end = microtime(TRUE);
-      $logger->log($this, $args, $query_end - $query_start);
+      $logger->log($this, $args, $query_end - $query_start, $query_start);
     }
 
     return $return;
diff --git a/core/tests/Drupal/KernelTests/Core/Database/LoggingTest.php b/core/tests/Drupal/KernelTests/Core/Database/LoggingTest.php
index 662f3ebbdb..449894c845 100644
--- a/core/tests/Drupal/KernelTests/Core/Database/LoggingTest.php
+++ b/core/tests/Drupal/KernelTests/Core/Database/LoggingTest.php
@@ -20,6 +20,7 @@ class LoggingTest extends DatabaseTestBase {
   public function testEnableLogging() {
     Database::startLog('testing');
 
+    $start = microtime(TRUE);
     $this->connection->query('SELECT [name] FROM {test} WHERE [age] > :age', [':age' => 25])->fetchCol();
     $this->connection->query('SELECT [age] FROM {test} WHERE [name] = :name', [':name' => 'Ringo'])->fetchCol();
 
@@ -32,6 +33,9 @@ public function testEnableLogging() {
 
     foreach ($queries as $query) {
       $this->assertEqual(__FUNCTION__, $query['caller']['function'], 'Correct function in query log.');
+      $this->assertIsFloat($query['start']);
+      $this->assertGreaterThanOrEqual($start, $query['start']);
+      $start = $query['start'];
     }
   }