Here is a patch discussed in http://archives.postgresql.org/pgsql-hackers/2007-02/msg00010.php
Concurrent vacuum will save n_dead_tuples value at the beginning. Stats collector will be subtract the value from n_dead_tuples instead of setting it to zero. The statistics accuracy of n_dead_tuples will be better, especially just after finish of a vacuum. The behavior in VACUUM FULL is not changed because concurrent updates are not allowed during VACUUM FULL. Comments welcome. Regards, --- ITAGAKI Takahiro NTT Open Source Software Center
n_dead_tuples.patch
Description: Binary data
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