Subject | Max() in view does not use index |
---|---|
Author | Bob Murdoch |
Post date | 2002-05-23T17:45:50Z |
I have a Calendar table, which contains all dates for a twenty year time
span. The table looks like this:
create table Calendar (
cal_date date,
fiscal_week integer,
fiscal_month integer,
fiscal_season integer,
fiscal_year integer)
I have seperate indexes on cal_date, fiscal_season, and fiscal_year.
I'm creating a view to select the last date of each week for a season:
create view fiscal_saturday as
select
fiscal_week, fiscal_month, fiscal_season, fiscal_year, max(cal_date)
from
calendar
group by
fiscal_week, fiscal_month, fiscal_year
If I run the following query against the view, no indexes are used:
select * from fiscal_saturday where fiscal_season = 0 and fiscal_year
= 2002
I'm assuming that the way the view works is that it has to build it's
result set first, then filter that to match the restrictions of the where
clause.
My question is simply how can I speed this up? I actually need to join
this to another table for selecting some data, and the 15000 reads against
the calendar table are killing it's performance.
tia,
Bob M..
span. The table looks like this:
create table Calendar (
cal_date date,
fiscal_week integer,
fiscal_month integer,
fiscal_season integer,
fiscal_year integer)
I have seperate indexes on cal_date, fiscal_season, and fiscal_year.
I'm creating a view to select the last date of each week for a season:
create view fiscal_saturday as
select
fiscal_week, fiscal_month, fiscal_season, fiscal_year, max(cal_date)
from
calendar
group by
fiscal_week, fiscal_month, fiscal_year
If I run the following query against the view, no indexes are used:
select * from fiscal_saturday where fiscal_season = 0 and fiscal_year
= 2002
I'm assuming that the way the view works is that it has to build it's
result set first, then filter that to match the restrictions of the where
clause.
My question is simply how can I speed this up? I actually need to join
this to another table for selecting some data, and the 15000 reads against
the calendar table are killing it's performance.
tia,
Bob M..