consider region distribution in optimization phase #19312
Labels
feature/accepted
This feature request is accepted by product managers
sig/planner
SIG: Planner
type/enhancement
The issue or PR belongs to an enhancement.
type/feature-request
Categorizes issue or PR as related to a new feature.
Feature Request
Is your feature request related to a problem? Please describe:
In the IMDB test, we found a case that two full index scans on different indexes with limitation have a huge gap on performance.
In this case, we only need the first cop-task's data since there is a
Limit 100
. And because these two indexes have different region distributions, the number of rows need to scan to finish the first cop-task are different.Describe the feature you'd like:
Consider region distribution in optimization phase for this case.
NOTE: introducing this physical information(region distribution) into the optimizer seems tricky, we need more discussion about this feature.
Describe alternatives you've considered:
No
Teachability, Documentation, Adoption, Migration Strategy:
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