I noticed a strange thing: for some days already I was surprised to see gaps in my data for the day before while I was pretty sure that the day before all data were recorded, tick after tick for the 20 symbols I am following from IB. I know it is not really tick-by-tick but rather 0.2/0.3 seconds interval but anyway: when I launch AB in the morning it does an automatic IB backfill and actually what happens is that almost all data for the day before are deleted and replaced, for the last 15 minutes of trading session, by a kind of compressed bars which never took place in that time compression frame(I use 75-tick for charting). And the bars before just disappeared! I now switched to 1-minute backfill in database settings and will se what happens. My point/question is: when you are connected to IB from the beginning of the session it is probably better not to backfill at all, right??
Thank you, Carl
