Hi

I have a table defined as:

CREATE TABLE POINT_KVIT
(
ID INTEGER NOT NULL,
BONNR INTEGER DEFAULT 0,
TEKST VARCHAR( 100) DEFAULT '' COLLATE NONE,
CONSTRAINT FK_POINT_KVIT PRIMARY KEY (ID)
);

CREATE ASC INDEX POINT_KVIT_IDX1 ON POINT_KVIT (BONNR);


This tables contains some 24 millions records.


The selectivity to index POINT_KVIT_IDX1 is 0,00000142520 or less


If I do a select like this:

Select
ID, BonNr, Tekst
from Point_Kvit
Where BonNr = 2236136

It fetches 31 records in hardly no time (0.062 secs) with this plan:
PLAN (POINT_KVIT INDEX (POINT_KVIT_IDX1))


If I on the other hand do a select like this:

Select
ID, BonNr, Tekst
from Point_Kvit
Where BonNr = 2236136
Order by ID

It fetches the same 31 records, but i now uses 2 seconds to do the same with this plan:
PLAN (POINT_KVIT ORDER RDB$PRIMARY240 INDEX (POINT_KVIT_IDX1))


My question is, why is there such a big difference in the to above Selects?


I need to have them ordered, so I get them in the same order they where inserted.
I have for now solved it by doing this select, which is as fast as the first one:

Select
ID, BonNr, Tekst,
BonNr || ID as P
from Point_Kvit
Where BonNr = 2236136
order by 4

Which also have the same PLAN as the first one.



Regards
Michael