reverted:
--- b/core/lib/Drupal/Core/Config/DatabaseStorage.php
+++ a/core/lib/Drupal/Core/Config/DatabaseStorage.php
@@ -84,10 +84,7 @@
   public function read($name) {
     $data = FALSE;
     try {
+      $raw = $this->connection->query('SELECT [data] FROM {' . $this->connection->escapeTable($this->table) . '} WHERE [collection] = :collection AND [name] = :name', [':collection' => $this->collection, ':name' => $name], $this->options)->fetchField();
-      $raw = $this->connection->query('SELECT [data] FROM {' . $this->connection->escapeTable($this->table) . '} WHERE [collection] = :collection AND [name] = :name ORDER BY collection, name', [
-        ':collection' => $this->collection,
-        ':name' => $name,
-      ], $this->options)->fetchField();
       if ($raw !== FALSE) {
         $data = $this->decode($raw);
       }
diff -u b/core/lib/Drupal/Core/Database/Driver/pgsql/Connection.php b/core/lib/Drupal/Core/Database/Driver/pgsql/Connection.php
--- b/core/lib/Drupal/Core/Database/Driver/pgsql/Connection.php
+++ b/core/lib/Drupal/Core/Database/Driver/pgsql/Connection.php
@@ -352,7 +352,7 @@
   }
 
   /**
-   * Retrieves a sequence name that is owned by the table and column.
+   * Retrieves a sequence name that is owned by the table and column..
    *
    * @param string $table
    *   A table name that is not prefixed or quoted.
@@ -386,7 +386,6 @@
   public function sequenceExists($name) {
     $args = [':name' => $name];
     return (bool) $this
-//       ->query("SELECT c.relname FROM pg_class as c INNER JOIN pg_namespace as ns ON (c.relnamespace = ns.oid) WHERE c.relkind = 'S' AND c.relname = :name", $args)
       ->query("SELECT c.relname FROM pg_class as c WHERE c.relkind = 'S' AND c.relname = :name", $args)
       ->fetchField();
   }
diff -u b/core/modules/system/system.install b/core/modules/system/system.install
--- b/core/modules/system/system.install
+++ b/core/modules/system/system.install
@@ -1567,8 +1567,6 @@
     // likely serial columns.
     $entity_types = \Drupal::entityTypeManager()->getDefinitions();
     // @var \Drupal\Core\Entity\EntityTypeInterface $entity_type
-    $sandbox['max'] = count($sandbox['tables']);
-    $sandbox['progress'] = 0;
     foreach ($entity_types as $entity_type) {
       $storage_class = $entity_type->getStorageClass();
       if (is_subclass_of($storage_class, SqlContentEntityStorage::class)) {
@@ -1595,10 +1593,14 @@
       }
 
     }
+
+    $sandbox['max'] = count($sandbox['tables']);
+    $sandbox['progress'] = 0;
+
   }
   else {
     // Adds ownership of orphan sequences to tables.
-    $to_process = array_slice($sandbox['tables'], $sandbox['progress'], 50);
+    $to_process = array_splice($sandbox['tables'], $sandbox['progress'], 50);
 
     // Ensures that a sequence is not owned first, then ensures that the a
     // sequence exists at all before trying to alter it.
diff -u b/core/modules/system/tests/fixtures/update/drupal-8.pgsql-orphan-sequence.php b/core/modules/system/tests/fixtures/update/drupal-8.pgsql-orphan-sequence.php
--- b/core/modules/system/tests/fixtures/update/drupal-8.pgsql-orphan-sequence.php
+++ b/core/modules/system/tests/fixtures/update/drupal-8.pgsql-orphan-sequence.php
@@ -4,7 +4,6 @@
 use Drupal\Core\Database\Database;
 
 $connection = Database::getConnection();
-
 $db_type = $connection->databaseType();
 
 if ($db_type === 'pgsql') {
diff -u b/core/modules/system/tests/modules/pgsql_test/pgsql_test.info.yml b/core/modules/system/tests/modules/pgsql_test/pgsql_test.info.yml
--- b/core/modules/system/tests/modules/pgsql_test/pgsql_test.info.yml
+++ b/core/modules/system/tests/modules/pgsql_test/pgsql_test.info.yml
@@ -6 +6 @@
-
+core: 8.x
only in patch2:
unchanged:
--- a/core/lib/Drupal/Core/Database/Driver/pgsql/Schema.php
+++ b/core/lib/Drupal/Core/Database/Driver/pgsql/Schema.php
@@ -958,7 +958,7 @@ EOD;
       // not when altering. Because of that, the sequence needs to be created
       // and initialized by hand.
       $seq = $this->connection->makeSequenceName($table, $field_new);
-      $this->connection->query("CREATE SEQUENCE " . $seq);
+      $this->connection->query("CREATE SEQUENCE " . $seq . " OWNED BY {" . $table . "}." . $field_new);
       // Set sequence to maximal field value to not conflict with existing
       // entries.
       $this->connection->query("SELECT setval('" . $seq . "', MAX(\"" . $field . '")) FROM {' . $table . "}");
@@ -1016,6 +1016,25 @@ EOD;
     }
   }
 
+  /**
+   * Alters the ownership of a sequence.
+   *
+   * This is used for updating orphaned sequences.
+   * See issue https://www.drupal.org/project/drupal/issues/3028706
+   *
+   * @param string $table
+   *   The unquoted or prefixed table name.
+   * @param string $column
+   *   The column name for the sequence.
+   *
+   * @internal
+   */
+  public function updateSequenceOwnership($table, $column) {
+    $seq = $this->connection->makeSequenceName($table, $column);
+    $table_name = $this->connection->prefixTables('{' . $table . '}');
+    $this->connection->query('ALTER SEQUENCE IF EXISTS ' . $seq . ' OWNED BY ' . $table_name . '.' . $column);
+  }
+
   /**
    * Retrieve a table or column comment.
    */