getting an index to work with partial indices ...

Try as I might, I can't seem to get it to work ... table has >9million
rows in it, I've created an index "using btree ( priority ) where priority
< 0;", where the table distribution looks like:

priority | count
----------+---------
-2 | 138435
-1 | 943250
1 | 3416
9 | 1134171
| 7276960
(5 rows)

And it still won't use the index:

# explain update table set priority = -3 where priority = -1;
QUERY PLAN
------------------------------------------------------------------
Seq Scan on table (cost=0.00..400735.90 rows=993939 width=278)
Filter: (priority = -1)
(2 rows)

But, ti will if I try 'priority = -2' ... what is teh threshhold for using
the index? obviously 10% of the records is too high ...

thanks ...

----
Marc G. Fournier Hub.Org Networking Services (http://www.hub.org)
Email: scrappy(at)hub(dot)org Yahoo!: yscrappy ICQ: 7615664