Hi All,

The specific JOIN SQL became slow then I checked the SQL with PLAN (set plan on in isql
environment). PLAN shows the SQL using 3 indexes. After I backup/restore the database,
I run the same JOIN SQL. PLAN shows the SQL using 1 index and it become fast. In my knoledge,
backup and restore optimize *physical* data, not *logical* data. I wonder why backup/restore
affect the PLAN of JOIN SQL.

I have two question.

Q1. This situation often occurs in operation of firebird ?
Q2. How do I avoid that JOIN SQL become slow? Can I predict with some tools?


[Environment]
Firebird: CS-1.5.0.4290-0
Linux: Red Hat Enterprise Linux ES release 3(Taroon Update2)
Middleware: JayBird1.5.5
Memory: 2G-byte

Regards,
KIMURA, Meiji(FAMILY, Given)
Tokyo, JAPAN