title: Segments is solr
body: <p>Can someone explain me what are semgents in solr.</p>
  
  <p>I have not found good description online.</p>
  
  <p>I have also seen various segments file in solr? what are there for.
  What happens if I delete one segment file.? will that corrupt the index?
  I am using solr 5.3(if that makes any difference)</p>
  
  <p>Also whar are tlogs and what are there role?</p>