estimated # of rows in a table could become inaccurate after deletes

Description

TokuDB uses TokuFT to provide an estimate of the number of rows in a fractal tree. TokuFT’s row estimate can be wildly wrong after a lot of deletes have occurred on a table. For example, we have seen a customer delete MOST of the rows from a table, and the row estimate was still 69M rows.

Since MySQL computes cardinality = #rows / #unique rows per key, if #rows is wrong, then cardinality is wrong.

Environment

None

Assignee

George Lorch

Reporter

Abdelhak Errami

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External issue ID

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Fix versions

Priority

Major
Configure