protected function SqlGroupGraphStorage::loadGroupMapping in Subgroup (Graph) 1.0.x

Fetch the records from graph for the provided group and cache them.

This is mostly done for performance reasons. When having lots of groups, getting/checking the ancestors or descendants in separate queries is a lot slower.

1 call to SqlGroupGraphStorage::loadGroupMapping()

SqlGroupGraphStorage::loadMap in src/Graph/SqlGroupGraphStorage.php

Load the ancestry mapping for a group if it isn't loaded already.

File

src/Graph/SqlGroupGraphStorage.php, line 108

Class

SqlGroupGraphStorage

SQL based storage of the group relationship graph.

Namespace

Drupal\ggroup\Graph

Code

protected function loadGroupMapping($gid) {
  $cid = "ggroup_graph_map:{$gid}";
  if ($cache = \Drupal::cache()
    ->get($cid)) {
    $mapping = $cache->data;
  }
  else {
    $query = $this->connection
      ->select('group_graph', 'gg')
      ->fields('gg', [
      'start_vertex',
      'end_vertex',
    ]);

    // This Or Group is identical to the one used in the query below.
    $or_group = $query
      ->orConditionGroup();
    $or_group
      ->condition('gg.start_vertex', $gid)
      ->condition('gg.end_vertex', $gid);

    // Add the Or condition Group.
    $query
      ->condition($or_group);
    $mapping['descendants'] = $query
      ->execute()
      ->fetchAll(\PDO::FETCH_COLUMN | \PDO::FETCH_GROUP);
    $mapping['ancestors'] = $query
      ->execute()
      ->fetchAll(\PDO::FETCH_COLUMN | \PDO::FETCH_GROUP, 1);

    // Now load direct relatives.
    $query = $this->connection
      ->select('group_graph', 'gg')
      ->fields('gg', [
      'start_vertex',
      'end_vertex',
    ]);

    // Add conditions to restrict this to direct descendants for this group.
    $query
      ->condition('hops', 0)
      ->condition($or_group);
    $mapping['directDescendants'] = $query
      ->execute()
      ->fetchAll(\PDO::FETCH_COLUMN | \PDO::FETCH_GROUP);
    $mapping['directAncestors'] = $query
      ->execute()
      ->fetchAll(\PDO::FETCH_COLUMN | \PDO::FETCH_GROUP, 1);

    // Descendants and Ancestors contain direct relatives as well.
    // Combine ancestors and descendants to get a full list of all of the
    // groups returned to tag this cache with.
    $groups = array_merge($mapping['descendants'], $mapping['ancestors']);
    $groups[] = $gid;

    // Build the cache tags for all of the (deduped) groups.
    $cache_tags = [];
    $groups = $this
      ->flattenGroups($groups);
    $groups = array_unique($groups, SORT_NUMERIC);
    foreach ($groups as $group_id) {
      $cache_tags[] = "group:{$group_id}";
    }
    \Drupal::cache()
      ->set($cid, $mapping, Cache::PERMANENT, $cache_tags);
  }

  // Merge relatives with those already set.
  $this
    ->mergeMappings($mapping);

  // Indicate that this group ID has been loaded.
  $this->loaded[$gid] = TRUE;
}