I used $LastRunTime variable for an incremental data fetch, and initially it was having the default value 1970-01-01 00:00:00.
After each run the variable was getting updated as expected. But I could see that, when there were no records having timestamp >$LastRunTime variable, the session was executing for a very longer duration (returning 0 records). Can anyone tell me the reason behind this.
As the Source table has huge volume, I have also given Push Down optimization option.