Provide a fix control switch to fix overestimation of index scan of inner side of index join #44855
Labels
affects-6.5
affects-7.1
sig/planner
SIG: Planner
type/enhancement
The issue or PR belongs to an enhancement.
Background
In some cases, tidb will produce an extremely high estimation for the
IndexRangeScan
under the inner side of anIndexJoin
. In #41996 we resolved this.But we reverted this change in #42362 because in an internal workload, it caused execution plan regression. As explained in #42362, it's not because something incorrect in #41996, but better estimation for one operator doesn't guarantee a better execution plan as a whole.
However, this improvement is important in some scenarios, and we want to make users able to use it when it's necessary. So we plan to add this to
tidb_opt_fix_control
.Usage
The text was updated successfully, but these errors were encountered: