planner: optimizer statistics cost too much amount of memory

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#46,149 opened on Aug 16, 2023 0 comments 0 reactions 2 assignees Claimed by @winoros View on GitHub

component/statistics sig/planner type/enhancement

Description

## Enhancement

750000 columns and indexes totally, even if some of them are not used, after initializing, the statistics cost 4G+ memory:

MySQL (none) select count (1) from mysql stats_histograms;

![image](https://github.com/pingcap/tidb/assets/7499936/30a47857-7661-4fc7-bb6f-c3ead475b81b)

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