Re: Important speed difference between a query and a

Frederic Jolliton <fred-pg@jolliton.com> writes:
>> To "emulate" a parametred view, I created a function as follow:
>>
>> CREATE FUNCTION get_info (integer) RETURNS SETOF type_get_info
>> AS '...' <- here the query show below, where 'LIMIT $1' is used instead of 'LIMIT 10'
>> LANGUAGE sql;

> So, the query in the function is not using index but the exact same
> query alone does !

But it's not the same query, is it?  With "LIMIT $1" the planner can't
know what the limit value is exactly, so it has to generate a plan that
won't be too unreasonable for either a small or a large limit.

            regards, tom lane