pgsql-bugs(at)postgresql(dot)org writes:
> CREATE TABLE obj_props(obj_id int8,name text,value text);
^^^^^^^^^^^
You need an explicit cast, like this:
EXPLAIN SELECT name,value FROM obj_props WHERE obj_id = 100::int8;
because the planner is not smart about converting cross-datatype
comparisons into indexscans, and unadorned "100" is taken as int4.
I think we will finally have a fix for this in 7.4.
regards, tom lane