index does not help on ranges

Assuming a simple table with 1.000.000 entries. One column is type
integer and running from 1 to 1.000.000 (sequence). There is an index
on this column, so queries like

select * from many where serial=784193;

are pretty fast. However, such simple queries like

select * from many where serial<10;

take very long time. The query doesnt use the index in this case. Is
this a problem on my side or is this a prinicipal thing ?

thnx,
peter

--
mag. peter pilsl

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email: pilsl@goldfisch.at
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