Subject Index makes select very slooooow!
Author karlzeift
Hi everyone!

I'm using FB 1.0, and I've been satisfied for years with its
performance and stability. I'm using it thorugh a framework, so I
cant use triggers and sp:s.

The problem I have now is that I'm running a pretty complex query
several times, and I thought I should speed up the execution. All of
them takes about 1.5 mins (all are the same, just the parameters are
different). I have indexes on all id fields, but not on my timestamp
column (called Created in the query).

To improve speed, I added a index on the column Created (type
timestamp), and I was very surprised that it took much much longer
time to execute the query, instead of 1.5 min, it took hours!!!! And
I dont have a lot of data, only 32K rows in the largest table! Does
any of you have an idea of how to speed this query up, since the
index is slowing it down instead of speeding up???

SELECT UnifiedMes_1.ID, UnifiedMes_1.TYPE
FROM UnifiedMessage UnifiedMes_1, Customer Customer_1 JOIN
Entity
Entity_1 ON (Entity_1.Customer = Customer_1.ID), GalaxyObject
GalaxyObje_1
WHERE UnifiedMes_1.Entity = Entity_1.ID
AND UnifiedMes_1.ID = GalaxyObje_1.ID
AND (Customer_1.ID = 34056)
AND (UnifiedMes_1.TYPE IN (37))
AND (((GalaxyObje_1.Created > :Param0) and
(GalaxyObje_1.Created <
:Param1)) and EXISTS (SELECT Design_1.ID
FROM Design Design_1, SendableDesignItem SendableDe_1 JOIN
UnifiedMessage
UnifiedMes_2 ON (SendableDe_1.ID = UnifiedMes_2.SendableDesignItem)
JOIN
DesignItem DesignItem_1 ON (SendableDe_1.ID = DesignItem_1.ID)
WHERE UnifiedMes_1.ID = UnifiedMes_2.ID
AND Design_1.ID = DesignItem_1.OwningDesign
AND (Design_1.Kind = 0)
))

regards

Karl