title: Locking when using Read Uncommitted
body: <p>I have a query which take a little while to run, so its run with the isolation level set to Read Uncommitted, the data can be dirty since its only used to give a quick overview of the system at a glance.</p>
  
  <p>The query on a good day (first thing in the morning) takes around 3-15 seconds to run. (Date sorting slows it down, its instant without the sort)</p>
  
  <p>But as the day starts it takes long and longer to run, it ends up taking > 2 minutes to run.</p>
  
  <p>What I noticed is the query seems to get a LOT of OBJECT/PAGE locks when its executed.</p>
  
  <p>What I don't understand is why its acquiring locks while its set to Read Uncommitted.</p>
  
  <hr>
  
  <p>One of the index's that the query uses is set to use Row/Page locking.</p>
  
  <p>My Q:</p>
  
  <p><img src="https://i.stack.imgur.com/rtU9R.png" alt="enter image description here"></p>
  
  <p>Does an index which is set to use row/page locks, cause the data to be locked when being accessed, even when the query is Read Uncommitted?</p>