A query plan uses loose index scan if “Using index for group-by” appears in the “Extra” column of the EXPLAIN output. In some plans though, “Using index for group-by (scanning)” appears. What does “(scanning)” mean and how is it different from the regular loose index scan?…
All posts by sreeharsha ramanavarapu
Optimization to skip index dives with FORCE INDEX.
Index dives are performed during the optimization phase to help decide which index to use. Currently when user specifies FORCE INDEX, optimizer still always calculates cost using index dives. Under some circumstances it is possible to avoid the index dives and this could speed up execution.…