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cardinality differences

in SQL Performance (MOSC) 2 commentsAnswered

On our 19.25 databases (Oracle Linux 8) we are comparing the Explain plan from the same query in 2 databases. It's all the same, but one runs slow and the other is good. The slow one has got all the same/similar numbers … EXCEPT for cardinality, where the slow one has numbers that are roughly double as compared to the one that is good.

The records in the tables are about the same as well. But how does he end up with such different numbers for cardinality ? What would explain such a difference ?

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