Tom Lane, 24.07.2012 16:23:
Thomas Kellerer <spam_ea...@gmx.net> writes:
DELETE FROM dupes
WHERE id NOT IN (SELECT min(b.id)
FROM dupes b
GROUP BY first_name, last_Name
HAVING count(*) > 1);
Doesn't that kill the non-duplicates too?
Ah right - another good point on how important the correct test data is ;)
Why does the usage of the CTID column change the plan so drastically?
IIRC, type tid doesn't have any hash support.
So the "bad" plan is expected?
Regards
Thomas
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