I have been investigating the dtime_% fields in the diff and chip stages for gpc1 for the month of October (and also September, see ProcessingTimesSept2010). The tag changed on 2010-10-29, which included a number of changes to the diff stage.

Diff Stage

There are 4 dtime columns for diff: dtime_match, dtime_script, dtime_phot and dtime_diff. dtime_diff is never set (it is always NULL). dtime_match and dtime_phot often have nulls (about 7% of the time). I excluded from my plots diff_ids with NULL values in any of the dtime columns (except for dtime_diff). For the 'old tag', I selected dates between 2010-09-28 and 2010-10-25, and for the 'new tag', I selected dates between 2010-10-29 and 2010-11-03.

• new tag = dotted lines
• old tag = solid lines

• Purple = dtime_script
• Green = dtime_phot
• Black = dtime_match

And here are the median times for each:

dtime	old tag(s)	new tag(s)	(old tag - new tag)(s)
dtime_match	54.4	40.4	14.0
dtime_phot	70.0	59.0	11.0
dtime_script	151.0	125.0	26.0