function dblog_cron

Implements hook_cron().

Controls the size of the log table, paring it to 'dblog_row_limit' messages.

File

core/modules/dblog/dblog.module, line 79

System monitoring and logging for administrators.

Code

function dblog_cron() {
  // Cleanup the watchdog table.
  $row_limit = config_get('system.core', 'log_row_limit');

  // For row limit n, get the wid of the nth row in descending wid order.
  // Counting the most recent n rows avoids issues with wid number sequences,
  // e.g. auto_increment value > 1 or rows deleted directly from the table.
  if ($row_limit > 0) {
    $min_row = db_select('watchdog', 'w')
      ->fields('w', array('wid'))
      ->orderBy('wid', 'DESC')
      ->range($row_limit - 1, 1)
      ->execute()->fetchField();

    // Delete all table entries older than the nth row, if nth row was found.
    if ($min_row) {
      db_delete('watchdog')
        ->condition('wid', $min_row, '<')
        ->execute();
    }
  }
}