I have two identical databases, one runs under FB 1.5.2 and one under FB
2.0. I have the following query

select BLPCID,sum(BLGROSS_SALES),sum(BLRETURNS),sum(BLNETSALES),
sum(BLDELIVERY_QUANTITY),sum(BLBACKLOG) from BACKLOG
where BLCSSALESREPID=56 and BLCSGPID3=65 and
not exists (select TO6PCID from TURNOVER_PC_CS join CUSTOMERS on
TO6CSID=CSID where CSUSID1=56 and CSGPID3=65 and BACKLOG.BLPCID=TO6PCID)
group by BLPCID

When I run it with FB 1.5.2, I get the plan
PLAN JOIN (CUSTOMERS INDEX (CUSTOMERS_IDX1),TURNOVER_PC_CS INDEX
(I_TO6ALL_A_U))
PLAN (BACKLOG ORDER I_BLPCID_BLMCID_A)

and the reads
BACKLOG 216 Indexed Reads (IR)
CUSTOMERS 2290 IR
TURNOVER_PC_CS 214 IR

When I run the query with FB 2.0, I get the plan
PLAN JOIN (TURNOVER_PC_CS INDEX (I_TO6PCID_A), CUSTOMERS INDEX
(RDB$PRIMARY26))
PLAN (BACKLOG ORDER I_BLPCID_BLMCID_A INDEX
(I_BLCSGPID3_BLPCPAID_BLPCMPID_A, BACKLOG_IDX1))

and the reads
BACKLOG 216 IR
CUSTOMERS 11992 IR
TURNOVER_PC_CS 11992 IR

I'm a little bit surprised, that the query has a lot more reads with FB
2.0. Exists a solution for FB 2.0, so that query runs as fast as with FB
1.5.2?

Regards

Guido