problems with interbase-gbak-restore

I have a problema with a GDB.
I execute a query into this gdb and the perfomance of this query is good, bat I make a
backup and restore to my gdb and I try to execute the same query and now the time to execute this query is very long.
The plan that ibserver uses to execute the query in both database is different. Why?
Is there any problem with gbak restore GDB's?

Firstly, thank you for you repply.
The setting deactive indexes was off when I made the restore and de size page was the same than the original GDB. I tried with a bigger size page but the result was worst.

When you did the restore, did you somehow turn the "Deactivate indices" setting on?



It sounds like this might have happened, and that's why the execution plans are different. The main reason for slower execution plans in InterBase is lack of indexes.



Another question, did you set the page size to the same setting during the restore?



If so, then you have cut the transactional cache down, and this is going to eat into your execution time. Also, if you managed to raise the page size higher than the server can support (for instance, going from 4096 to 8192), you're actually crippling the InterBase server by doing so, because each transactional page still has to be broken into two packets to be returned to the client.