Hello all,
I have an insert statement as Insert into T2(a,b,c) select (a,b,sum(c)) from T1. T1 has 1 million+ rows. The select statement itself takes 20 seconds. I don't have any indexes on T1. I was wondering if I could the make insert statement faster. I have few doubts regarding the same. Does /*+append*/ really help here as I read somewhere this hint just appends the new rows into the table thus increasing the HWM, ultimately, make the FTS slower later on. And what hints would be appropriate with DMLs like these, where there is no joins in the select statement (just one table)?

Appreciate your valuable inputs,
gtcol