Questions on upgrade and migrate database from Oracle 7.3.4 to Oracle 8i/9i

[shirleykwan]

Upgrade database from Oracle 7.3.4 to Oracle 8i/9i



Will database performance degrade when I migrate database from Oracle 7.3.4 to Oracle 8i/9i ? "The execution plant may change a lot if Oracle migrate to 9i." Is this statement true ?


Thanks a lot for your help !!!

[JChiappa]

I´m doing it right now ( 7.3.4.5 => 8.1.7.4) , and for 8i I can say : in the SAME hardware, SAME application, IF you don´t install new stuff (HTTP server, java, etc), and IF you use in 8i exactly the SAME params (ie, block buffers, optimizer_mode, compatible, etc, etc), the performance WILL be mostly untouched (neither better or worse). Granted, the 8i database executables occupies MORE RAM, but is just one or two dozens of megabytes, nothing to worry in a production server.

Regards,

Chiappa

[pando]

Originally posted by shirleykwan
[BWill database performance degrade when I migrate database from Oracle 7.3.4 to Oracle 8i/9i ? "The execution plant may change a lot if Oracle migrate to 9i." Is this statement true ?
[/B]

well not exactly degrade, it must be better, it's matter of how you set the parameters properly, there are new parameters from 7 to 9i obviously

the execution plan would change, you have to check the parameters as well

[jrpm]

It depends on the Oracle parameters. As said, if EVERYTHING is identical, you nominally should get better performance. One key is if you are using RBO or CBO. If CBO, then you need to update the statistics and probably do a little tuning (there are changes to the optimizer).

When we upgraded from 7.3 to 8.1.6, we found that CBO had been turned on somehow (I wasn't on the team) and spent about a week retuning some major queries.