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();
    }
}