Piwik\Plugins\PrivacyManager\Controller::getDeleteDBSizeEstimate PHP Method

    protected function getDeleteDBSizeEstimate($getSettingsFromQuery = false, $forceEstimate = false)
    {
        $this->checkDataPurgeAdminSettingsIsEnabled();
        // get the purging settings & create two purger instances
        if ($getSettingsFromQuery) {
            $settings = $this->getPurgeSettingsFromRequest();
        } else {
            $settings = PrivacyManager::getPurgeDataSettings();
        }
        $doDatabaseSizeEstimate = PiwikConfig::getInstance()->Deletelogs['enable_auto_database_size_estimate'];
        // determine the DB size & purged DB size
        $metadataProvider = StaticContainer::get('Piwik\\Plugins\\DBStats\\MySQLMetadataProvider');
        $tableStatuses = $metadataProvider->getAllTablesStatus();
        $totalBytes = 0;
        foreach ($tableStatuses as $status) {
            $totalBytes += $status['Data_length'] + $status['Index_length'];
        }
        $formatter = new Formatter();
        $result = array('currentSize' => $formatter->getPrettySizeFromBytes($totalBytes));
        // if the db size estimate feature is enabled, get the estimate
        if ($doDatabaseSizeEstimate || $forceEstimate == 1) {
            // maps tables whose data will be deleted with number of rows that will be deleted
            // if a value is -1, it means the table will be dropped.
            $deletedDataSummary = PrivacyManager::getPurgeEstimate($settings);
            $totalAfterPurge = $totalBytes;
            foreach ($tableStatuses as $status) {
                $tableName = $status['Name'];
                if (isset($deletedDataSummary[$tableName])) {
                    $tableTotalBytes = $status['Data_length'] + $status['Index_length'];
                    // if dropping the table
                    if ($deletedDataSummary[$tableName] === ReportsPurger::DROP_TABLE) {
                        $totalAfterPurge -= $tableTotalBytes;
                    } else {
                        if ($status['Rows'] > 0) {
                            $totalAfterPurge -= $tableTotalBytes / $status['Rows'] * $deletedDataSummary[$tableName];
                        }
                    }
                }
            }
            $result['sizeAfterPurge'] = $formatter->getPrettySizeFromBytes($totalAfterPurge);
            $result['spaceSaved'] = $formatter->getPrettySizeFromBytes($totalBytes - $totalAfterPurge);
        }
        return $result;
    }