Hi! All I ran a query once with hash hint and then without it These are the results Scan count 17, logical reads 66391, physical reads 434, read-ahead reads 65358, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0. This with hash hint ran for 36 min and the second one ran for 15 min Scan count 17, logical reads 66536, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0. Did the execution time reduce due to caching or is it better not to include hash hint also have a question whether it is better to drop and create indexes or DISABLE and REBULD for an ETL process Thanks a lot
You need to be extremely cautious using query hints. Most of the time they either don't help or hurt your performance. I avoid them like crazy. You may have seen caching too, which is why I usually run a query twice while I'm testing it. Either approach for you ETL works. I find disabling and rebuilding to be safer because then I don't accidentally lose an index.