Re: An impossible thing to guess, but...

On Thu, 2 Jul 1998 15:12:44 -0400, "Narkinsky, Pat" <Pat.Narkinsky@rivhs.com> wrote: > >I have an Informix 7.14UD7 database running a vertical application. > >The vendor of this application has told me that, in order to fix some >significant performance problems we have been having, I need to: >1) Upgrade Informix from 7.14UD7 to 7.24.UC5 >2) Rebuild the database by dropping it (using dbexport) and then >importing it (using dbimport). There may be a direct upgrade path from one to the other so you don't have to do dbexport/dbimport. Check that with your local Informix office. >However, I have not been able to get any kind of accurate guess as to >how long this process should take. Can anyone make an educated guess? >I'm running an IBM RS/6000 S70 12-way, with 8GB memory, 64GB disk. I >have approximately 6GB of data actually in the database. On a Compaq Proliant 1500 with a single 100MHz Pentium and 2GB of data dbexport used a few hours. On a Dell 4200 with a single 300MHz Pentium dbimport was was much faster than the export. On your machine it will of course be a lot faster again. Why don't you simply test it. Of course you need the diskspace and some time with no users on for that. Be aware that there *might* be some problems with dbexport/dbimport in generating individual files larger than 2GB even if you should have a 64bit port of the engine. This should only be a problem if one of your tables are so large that the dbexport format will create such a large file. In many cases the exported file is smaller than the table is inside the engine. >Also, can anyone guess what kind of performance impact this might have? >This system is primarily Transaction oriented. As far as I remember the general performance increase is on the order of 30%. However the optimizer is much better so for some types of queries you may see a much larger increase. Going to version 7.3 you should get yet another increase of perhaps 30% or more with an even better optimiser giving better results on more queries. >I know these are impossible questions, but if anyone can venture a guess >I would appreciate it. These where wild guesses. 7.14 is however so old by now that an upgrade is soon overdue. Nils Myklebust NM Data AS Norway E-mail: Nils.Myklebust@nmdata.com FAQ at: http://www.iiug.org/techinfo/faq/faq_top.html (Now with ODBC info under "Third party products".)