Hi,
I was working on this simple query
select field1 from table A
where A.field2 <= some_value
order by 1 desc limit some_value
and I saw that:
1) the planner on this query uses an index only scan method:
select field1 from table A
where A.field2 <= '2014-08-13 10:20:59.99648+02'
order by 1 desc limit 100
2) the planner on this query uses a classic index scan method:
select field1 from table A
where A.field2 <= '2014-08-13 10:20:59.99648+02'
order by 1 desc limit 1
the only difference between the two queries is the limit clause,
for the first query the limit is 100 and for the second the limit is 1
it seems a little bit strange...someone can help me to understand why?
My develop PostgreSQL version is a 9.4 beta
regards,
Enrico
--
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