time lag on data written to logfiles

I was trying to verify windspeed units in the logfiles to what was showing on WD’s dials and having trouble correlating them. So I thought I would watch when the temperature changed on WD’s display, and see when the change was recorded in both the logfile, and the MySQL database.

The result was as expected for the MySQL database (change seen in the data for the next minute).

However, there seems be a lag of around 2 minutes (plus and minus) before the change is seen in the logfile (see attachment).

The time when the temperature change was observed was taken from the clock on WD’s display.

Have others noticed this? (It’s no big issue, but just a bit puzzling)

UPDATE: There was no time lag on data I checked from earlier this month !


Logging time lag.JPG