2 Instances, 1 machine VS 1 Instance 2 databases

Greetings, The current job I find myself in was setup with 2 INFORMIX instances each with one database. (On the same machine.) We have applicattions that link to both concurrently and do work. I would THINK that ONE instance with TWO databases (giving the one instance all the CPU, DISK etc that BOTH originally had) would end up being FASTER than the current scenario. Anybody have ANY experience with this kind of situation? (The current project lead thinks the database engine is the bottleneck....... I'm thinking that it's the application code AND things like this architecture. Although in defense of the architecture... I think the original developers thought they may some day put each instance on a DIFFERENT machine. But NOT SO.) We've recently started using the STATEMENT CACHE and had a major increase... although we had to "LOOP OUT" a lot of the SQL code because it was written in such a manner that it was NOT cacheable. (I will be fixing that SOON.) Anyway.... any real world or benchmark info on the 2 instace - 1 db each VS 1 instance 2 db would be GREATLY appreciated. (I have not seen any documentation concerning this in the Informix Performance manual. Although I WILL be perusing the manuals this afternoon.) Thanks, Keith L Morris keith.l.morris@wcom.com

Here`s another situation. I am working on a system with two instances and one database in each instances. The databases are used by two different applications. When you upgrade one application (and usually the database at the same time) you do not want to have one's problems mixing with the others. So in this case if by any means a database/application combination makes one instance crash, the other application is still running. If the interaction between the two databases are such that they cannot operate independently, then why two instances ? Hope this will help Fran'ois lahaye.hogue@videotron.ca Keith L Morris a 'crit dans le message <397741FA.62AAA488@wcom.com>... >Greetings, > >The current job I find myself in was setup with 2 INFORMIX instances >each with one database. (On the same machine.) > >We have applicattions that link to both concurrently and do work. > >I would THINK that ONE instance with TWO databases (giving the one >instance all the CPU, DISK etc that BOTH originally had) would end up >being FASTER than the current scenario. > >Anybody have ANY experience with this kind of situation? > >(The current project lead thinks the database engine is the >bottleneck....... I'm thinking that it's the application code AND things >like this architecture. Although in defense of the architecture... >I think the original developers thought they may some day put each >instance on a DIFFERENT machine. But NOT SO.) > >We've recently started using the STATEMENT CACHE and had a major >increase... although we had to "LOOP OUT" a lot of the SQL code because >it was written in such a manner that it was NOT cacheable. (I will be >fixing that SOON.) > >Anyway.... any real world or benchmark info on the 2 instace - 1 db each >VS 1 instance 2 db would be GREATLY appreciated. > >(I have not seen any documentation concerning this in the Informix >Performance manual. Although I WILL be perusing the manuals this >afternoon.) > >Thanks, >Keith L Morris >keith.l.morris@wcom.com >