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full text search

The full text search doesn't seem to help really because it searches through all fields... (?)
Plus it gives me results I don't even understand where they come from! The Lucene search score is sometimes only a few percent but the result is there even though I really have no clue where it found the exact phrase and part that I'm looking for - and I don't want the system speculating on what I might have meant but just give me exactly what I ask for..
How can I accomplish that?
One answer

Large strings can only be searched with the full text search - that attribute if you add it to a query tells you.
Medium and small string support "Contains" that you can try.
Comments

I was afraid so - though that's absolutely ridiculous for just about all searches and queries we need to do!
Is there any other way/workaround to solve that problem - I mean, this is major really!
And could you explain the result from the full text search? For me there's not the slightest logic behind that to be honest

The below article should give you a better idea.
https://jazz.net/library/article/824
Basically, almost everything you "type" goes into the _content category. Also, the other categories may give you an unexpected result. Let's say there is an attribute called "Approved By" in the work item, and when you search "approved", you may be thinking of work items with comments or descriptions containing "approved", but in fact all work items with the "Approved By" attribute populated will appear in the result set.
1 vote

You can always come up with enhancement requests for the query model. I found things I wanted changed and did.

Well, it's not about an enhancement - it's about getting what one would expect. If I search something and the term is not part of any of the work items I don't want to get any results - with the Lucene search (that I can't seem to configure at all if I'm right?) I am getting results that I am absolutely not interested in and I cannot do anything about it.
It's not that an enhancement is needed - a whole new search and query model is needed. It's nice if a search is fast, but if I'm getting results that are - rubbish to be frank - the whole thing isn't worth anything I'm afraid.
How am I supposed to "sell" this to any users?

I have learned over the last 20 odd years that what I expect is not necessarily what others expect and, with respect to software, is implemented in said software.
The tools are in heavy usage for years and they work as designed. If your expectations don't agree with the design and implementation than an enhancement request is the only way to go.