Gaetano Mendola wrote:
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Hi all, take a look at those plans:
test=# explain analyze SELECT COUNT(id) FROM t_oa_2_00_card WHERE
pvcp in (select id from l_pvcp where value ilike '%pi%');
-> Hash IN Join (cost=2.22..153835.49 rows=177404 width=8) (actual
time=2.908..4001.814 rows=7801 loops=1) Hash Cond: ("outer".pvcp =
"inner".id)
Isn't too much choose a sequential scan due to 19 estimated rows when
with 4 estimated does a correct index scan ?
I don't think it's the matches on l_pvcp that's the problem, it's the
fact that it thinks its getting 177404 rows matching the IN.
Now, why 19 rows from the subquery should produce such a large estimate
in the outer query I'm not sure. Any strange distribution of values on pvcp?
--
Richard Huxton
Archonet Ltd
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