I have 3 tables:
1. Agent (0 row)
2. AR_PM (4,300+ rows)
3. AR_KnockOff (18,000+ rows)
I execute the following statement in Firebird 2.1.1:
SELECT A.Code FROM AGENT A, AR_PM B, AR_KnockOff C
It takes long times to get the first response back to my client software (IB Expert). However, this situation doesn't happen on Firebird 1.5 running the same query and same amount of data.
Firebird 2.1.1: 173 seconds
Firebird 1.5.X: 0 seconds
If I append one row into AGENT table, I get the response immediately after running the query:
Firebird 2.1.1: 0.093 seconds
Firebird 1.5.X: 0.031 seconds
I suspect there is some problem with Firebird 2.X. I also attach my database backup for both Firebird 1.5 and 2.1 for you to try out. Please pay attention on the time spent to run the query on Case 1.