protected function getLagFromSlaveStatus() {
$res = $this->query( 'SHOW SLAVE STATUS', __METHOD__ );
$row = $res ? $res->fetchObject() : false;
+ // If the server is not replicating, there will be no row
if ( $row && strval( $row->Seconds_Behind_Master ) !== '' ) {
return intval( $row->Seconds_Behind_Master );
}
protected function getLagFromPtHeartbeat() {
$options = $this->lagDetectionOptions;
+ if ( $this->trxLevel ) {
+ // Avoid returning higher and higher lag value due to snapshot age
+ // given that the isolation level will typically be REPEATABLE-READ
+ $this->queryLogger->warning(
+ "Using cached lag value for {db_server} due to active transaction",
+ $this->getLogContext( [ 'method' => __METHOD__ ] )
+ );
+
+ return $this->getTransactionLagStatus()['lag'];
+ }
+
if ( isset( $options['conds'] ) ) {
// Best method for multi-DC setups: use logical channel names
$data = $this->getHeartbeatData( $options['conds'] );
// Note: this would use "TIMESTAMPDIFF(MICROSECOND,ts,UTC_TIMESTAMP(6))" but the
// percision field is not supported in MySQL <= 5.5.
$res = $this->query(
- "SELECT ts FROM heartbeat.heartbeat WHERE $whereSQL ORDER BY ts DESC LIMIT 1"
+ "SELECT ts FROM heartbeat.heartbeat WHERE $whereSQL ORDER BY ts DESC LIMIT 1",
+ __METHOD__
);
$row = $res ? $res->fetchObject() : false;
} finally {