"Should I use multiple indices in Solr?", and some other quick Q

Question

Imagine a classifieds website, a very simple one where users don't have login details.

I have this currently with MySql as a db. The db has several tables, because of the categories, but one main table for the classified itself. Total of 7 tables in my case.

I want to use only Solr as a "db" because some people on SO thinks it would be better, and I agree, if it works that is.

Now, I have some quick questions about doing this:

1. Should I have multiple scheema.xml files or config.xml files?
2. How do I query multiple indices?
3. How would this (having multiple indices) affect performance and do I need a more powerful machine (memory, cpu etc...) for managing this?
4. Would you eventually go with only Solr instead of what I planned to do, which is to use Solr to search and return ID numbers which I use to query and find the classifieds in MySql?

I have some 300,000 records today, and they probably won't be increasing.

I have not tested how the records would affect performance when using Solr with MySql, because I am still creating the website, but when using only MySql it is quite slow. I am hoping it will be better with Solr + MySql, but as I said, if it is possible I will go with only Solr.

Thanks

Answer 1

4 : If an item has status fields that get updated much more frequently than the rest of the record then it's better to store that information in a database and retrieve it when you access the item. For example, if you stored your library book holdings in a solr index, you would store the 'borrowed' status in a database. Updating Solr can take a fair bit of resources and if you don't need to search on a field it doesn't really need to be in Solr.