title: Why am I getting an index scan for a covered query using aggregate function?
body: <p>I have a query:</p>
  
  <pre><code>select min(timestamp) from table
  </code></pre>
  
  <p>This table has 60+million rows, and daily I delete a few off the end.  To determine whether or not there is any data old enough do delete I run the query above.  There is an index on timestamp ascending, containing only one column, and the query plan in oracle causes this to be a full index scan.  Should this not be the definition of a seek?</p>
  
  <p>edit including plan:</p>
  
  <pre><code>| Id  | Operation                  | Name       | Rows  | Bytes | Cost (%CPU)| Time     |
  |   2 |   INDEX FULL SCAN (MIN/MAX)| NEVENTS_I2 |     1 |     8 |     4   (100)| 00:00:01 |
  |   1 |  SORT AGGREGATE            |            |     1 |     8 |            |          |
  |   0 | SELECT STATEMENT           |            |     1 |     8 |     4   (0)| 00:00:01 |
  </code></pre>