/**
* Calculate valid timestamp boundaries for aggregation table usage
*
* table: --data-- -----aggregate----- -data-
* timestamp: from ... aggFrom ..... aggTo ... to
*
* @param string $type aggregation level (e.g. 'day')
* @return boolean true: aggregate table contains data, aggFrom/aggTo contains valid range
* @author Andreas Goetz <*****@*****.**>
*/
private function getAggregationBoundary($aggFromDelta = null)
{
$dateFormat = Util\Aggregation::getAggregationDateFormat($this->aggLevel);
// day = "%Y-%m-%d"
// aggFrom becomes beginning of first period with aggregate data
$sqlParameters = array($this->channel->getId(), $this->aggType, $this->from);
if (isset($aggFromDelta)) {
// shift 'left' border of aggregate table use by $aggFromDelta units
$sql = 'SELECT UNIX_TIMESTAMP(' . 'DATE_ADD(' . 'FROM_UNIXTIME(MIN(timestamp) / 1000, ' . $dateFormat . '), ' . 'INTERVAL ' . $aggFromDelta . ' ' . $this->aggLevel . ')) * 1000 ' . 'FROM aggregate WHERE channel_id=? AND type=? AND ' . ' UNIX_TIMESTAMP(FROM_UNIXTIME(timestamp / 1000, ' . $dateFormat . ')) * 1000 >=?';
} else {
// find 'left' border of aggregate table after $from
$sql = 'SELECT UNIX_TIMESTAMP(FROM_UNIXTIME(MIN(timestamp) / 1000, ' . $dateFormat . ')) * 1000 ' . 'FROM aggregate WHERE channel_id=? AND type=? AND ' . ' UNIX_TIMESTAMP(FROM_UNIXTIME(timestamp / 1000, ' . $dateFormat . ')) * 1000 >=?';
}
$this->aggFrom = $this->conn->fetchColumn($sql, $sqlParameters, 0);
$this->aggTo = null;
// aggregate table contains relevant data?
if (isset($this->aggFrom)) {
// aggTo becomes beginning of first period without aggregate data
$sqlParameters = array($this->channel->getId(), $this->aggType);
$sql = 'SELECT UNIX_TIMESTAMP(' . 'DATE_ADD(' . 'FROM_UNIXTIME(MAX(timestamp) / 1000, ' . $dateFormat . '), ' . 'INTERVAL 1 ' . $this->aggLevel . ')) * 1000 ' . 'FROM aggregate WHERE channel_id=? AND type=?';
if (isset($this->to)) {
$sqlParameters[] = $this->to;
$sql .= ' AND timestamp<?';
}
$this->aggTo = $this->conn->fetchColumn($sql, $sqlParameters, 0);
}
if (self::$debug) {
printf("from .. aggFrom .. aggTo .. to\n");
printf("%s |%s .. %s| %s\n", self::pd($this->from), self::pd($this->aggFrom), self::pd($this->aggFrom), self::pd($this->to));
}
return isset($this->aggFrom) && isset($this->aggTo) && $this->aggFrom < $this->aggTo && $this->from <= $this->aggFrom && $this->aggTo <= $this->to;
}
