Yuanjia Zhang comments

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Yuanjia Zhang

Incubating Program: Plan Change Capturer

PTAL @zz-jason @SunRunAway

Error execute insert statement with date type using the prepare api

@fzzf678 Could you take a look at this issue?

Error execute insert statement with date type using the prepare api

> 各位老师麻烦问下，这个问题在哪个版本修复，有计划吗? We'll fix it next week.

planner: LRUPlanCache memory trace

/merge

planner: fix unstable test TestDAGPlanBuilderUnionScan

/merge

planner: don't push down topN when the expressions in projection is mutable effective

/merge

The Plan of TPCH Q3 changes without any data update leading to 13s performance regression

Reason why the plan is unstable: 1) costs of these 2 plans (HJ and INLJ) are too close in cost-model-ver1 (as @Yisaer said), 2) the randomness of statistics is amplified...

planner: tidb_shard does not work with mpp

PTAL @winoros

Query optimizer choose to do table scan while index seek is possible

Thanks for your feedback @darkelf21cn , I have reproduced this case on my computer. I will investigate this problem soon.

Query optimizer choose to do table scan while index seek is possible

The reason is tricky and it is caused by a restriction on TiDB's optimizer. **Background**: the optimizer requires the inner child of `IndexJoin` must be a `DataSource(TableScan/IndexLookUp/IndexScan)`, you can see...