postgresql select where is null takes too long

[sergiui]

Hi,

I have a TABLE with many rows (about 1000 000) I want to get all the fields that have the value on colum A null.
Field A is integere and is indexed with a default btree.

My query is:
"SELECT * FROM table WHERE A is null"

this takes forever and eventualy returns nothing even if i do a simple "SELECT * FROM table LIMIT 1000" i can see that a have null values on the colum.

I think that null values are not indexed in postgresql or the index is not use properly.
Does anyone have an ideea?

Thank You!

 

[sergiui]

Found the solution, i had to many nulls 90%, you may delete the post sry...