In an upgraded SharePoint 2013 site collection, I have a custom property - "Media Number" which is a single line of text field because the value is usually a few letters followed by a few numbers. When searching for values in this field I either get no results for a partial match or a few results using a wildcard match. So let's say I have items with media numbers like MYMN12345 - if I type MYMN into the search I would expect to potentially get hundreds of search results. Instead I get nothing. If I type MYMN* I also usually get nothing but sometimes it seems like I'll get some pages (views) - no actual documents come up in the search results. The same thing happens if I type in the whole value. This field is indexed and I added it to the managed properties in the site collection search schema. Really this should be searchable and I have no idea why it's not. Does anybody know how I can get my custom properties to be searchable?
This field is literally the most important field people might be searching for on our site.
This might be related to a separate issue I'm having (maybe they're the same issue), I realize - I looked at the search service application's crawl log and notice there were 700+ errors:
The SharePoint item being crawled returned an error when requesting data from the web service. ( Error from SharePoint site )
Additionally, a deeper review of the crawl logs shows the crawler was getting 790~ successes as of a week ago, and about 3 days ago the error message above started happening. Of things that have been happening - added external URL and possibly Anonymous access (don't remember exactly when these things were added).
UPDATE with SOLUTION **
OK, so my real problem was twofold - first, my crawling was actually broken due to not having my zones (default, internet, etc) configured correctly. Second, I think I was expecting SharePoint search to work like Google. It does not.
To fix the crawling issue I made sure I had my web application in the default zone with NTLM configured for access and the crawl account and everything. I then extended the web application to the Extranet zone and set that extended zone up with anonymous access and FBA and everything.
To deal with the searching, I think I never really had a problem in the first place. To search by a partial word you can use the standard Windows * wildcard which is counter-intuitive to how most people think of searching, I think. Otherwise, like Mike said you can specify the field and the entire value you're searching for. Configuring your managed properties to be case-insensitive probably also helps.