Database size question

Question

Hi all, 
 
 When installing Appian in a new POSTGRESQL database, do the schemas (primary and secundary) need to be created previously or will the installation process create them? 
 
 Is there are any recommendation with regards to the size of the database? A customer wants to know how big should be the database for only one application. The Database will contain both the primary and the secondary schemas. 
 
 Thanks a lot

Dave Lewis · Answer

I think you'll find in the local install instructions that you set up the schemas in advance, because your configuration settings are going to ask for paths to those schemas in order to connect to them. I think the Appian schema is fairly small, and there's probably guidelines for the exact size needed for that. The next size up should be sufficient, because I don't think that schema really grows. 
 For your Business schema, that's the one that's going to grow. Plan your usage for the first year or two, calculate as precisely as you possibly can how much data you're going to generate down to the last kilobyte, based on your client's specifications, usage projections, table sizes, projections of how many whatevers are going to be generated daily and their average expected size, all the data you can get from the legacy system I assume you're replacing, crunch every last number you can get to find the total data required, then DOUBLE or QUADRUPLE that figure. We're engineers. We calculate the total weight of all the fully loaded tractor-trailers that could possibly fit on the bridge and make the bridge to hold ten times that weight exactly.