"Weber, Geoffrey M." <[EMAIL PROTECTED]> writes:
> Hmm - good question! However, it is - both the id and
> not_displayed_id are INTEGERs.
Well, in that case it must be a statistics issue --- does the indexed
column have a badly skewed distribution?
You could investigate how many rows the planner thinks will be fetched
via
PREPARE foo(int) AS
SELECT ah.* FROM alert ah where ( (ah.replaced_by_id = '0') AND
(not_displayed_id = $1 ) ) ORDER BY replaced_by_id, not_displayed_id;
EXPLAIN EXECUTE foo(42);
which will set up exactly the same planning situation as occurs in the
plpgsql function: no knowledge of the exact value being compared to.
regards, tom lane
---------------------------(end of broadcast)---------------------------
TIP 9: In versions below 8.0, the planner will ignore your desire to
choose an index scan if your joining column's datatypes do not
match
