MySQL table stats code cleanup #19391
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hashhar
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Oct 13, 2023
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| (SELECT CARDINALITY AS row_count FROM INFORMATION_SCHEMA.STATISTICS | ||
| WHERE TABLE_SCHEMA = :schema AND TABLE_NAME = :table_name | ||
| AND CARDINALITY IS NOT NULL) |
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I suppose it's never possible for cardinality of any index to be > actual row count?
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i would guess this is still an estimate
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Previously the MySQL estimated table row count was calculated taking into account the CARDINALITY of single column indexes, and cardinality of first column in multi-column indexes. This commit expands this to include cardinality of every index.
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