Subject Using right indeces in plan
Author Martin
Hi all,
I got a little problem with FB. Briefly, got a table with these cols:

type varchar(10)
day int
month int
year int
datecol date
and other columns...

(datecol contains the same date as in day. month. year)

and also two indeces:
1) type, year, month, day
2) type, datecol

(there are about milions rows in the table and I need to prefer speed
to disk space)

And now my problem - when I use query like (FB 1, dialect 3)
"SELECT type, x, y, z FROM tab WHERE type='sometype' AND
datecol='1.8.2003'" I would expect, that FB will use in its plan the
second index (type, datecol), but it always uses the first one. I
tried to influence FB to change its plan with inserting braces and
other conditions in where clause, but it always prefere to use index
"type, year, month, day". I don't want to use plan definition in query
since FB 1.5 could make problems. Please, got anyone an idea, how to
change the query to make FB using "type, datecol" index? (This index
is faster as I know when I specified it in plan.) Thanks.

Martin (mailto:moirae@...)