function search_update_totals

Updates the {search_total} database table.

This function is called on shutdown to ensure that {search_total} is always up to date (even if cron times out or otherwise fails).

File

modules/search/search.module, line 373

Code

function search_update_totals() {
  // Update word IDF (Inverse Document Frequency) counts for new/changed words.
  foreach (search_dirty() as $word => $dummy) {
    // Get total count
    $total = db_query("SELECT SUM(score) FROM {search_index} WHERE word = :word", array(
      ':word' => $word,
    ), array(
      'target' => 'slave',
    ))->fetchField();
    // Apply Zipf's law to equalize the probability distribution.
    $total = log10(1 + 1 / max(1, $total));
    db_merge('search_total')->key(array(
      'word' => $word,
    ))
      ->fields(array(
      'count' => $total,
    ))
      ->execute();
  }
  // Find words that were deleted from search_index, but are still in
  // search_total. We use a LEFT JOIN between the two tables and keep only the
  // rows which fail to join.
  $result = db_query("SELECT t.word AS realword, i.word FROM {search_total} t LEFT JOIN {search_index} i ON t.word = i.word WHERE i.word IS NULL", array(), array(
    'target' => 'slave',
  ));
  $or = db_or();
  foreach ($result as $word) {
    $or->condition('word', $word->realword);
  }
  if (count($or) > 0) {
    db_delete('search_total')->condition($or)
      ->execute();
  }
}