stats: refine the row count estimation for unknown values #7175
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alivxxx
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component/statistics
type/enhancement
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/run-all-tests |
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LGTM |
alivxxx
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Jul 30, 2018
coocood
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What have you changed? (mandatory)
Before this PR, when are queries on values that stats do not know, we simply regard them as do not exist. However, stats may not up to date. This PR refine the estimation methods for unknown values:
Fix #7127
What is the type of the changes? (mandatory)
How has this PR been tested? (mandatory)
Unit test.
Does this PR affect documentation (docs/docs-cn) update? (mandatory)
No.
Does this PR affect tidb-ansible update? (mandatory)
No.
Does this PR need to be added to the release notes? (mandatory)
No.
Refer to a related PR or issue link (optional)
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PTAL @coocood @zz-jason @winoros