pingcap/tidb
GitHub で見るSupport to use the outer side of the (Anti) Semi Join to build the hash table
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#32,335 opened on 2022年2月14日
help wantedsig/plannertype/enhancement
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説明
Enhancement
Currently, when TiDB meets a(an) (Anti) Semi join, it would always choose the inner side to build the hash table. When the inner side is extremely large compared with the outer side, our current strategy would cost a lot on building the hash table by the inner side.
So we should support constructing the hash table by the outer side to speed up the execution when the data distribution is like the above case.
It's something the same with supporting constructing hash table by the outer side of the outer join, which is implemented in TiDB.