title: How to obtain the size of a BLOB without reading the BLOB's content
body: <p>I have the following questions regarding BLOBs in sqlite:</p>
  
  <ul>
  <li>Does sqlite keep track of sizes of BLOBs? </li>
  <li>I'm guessing that it does, but then, does the length function use it, or does it read the BLOB's content?</li>
  <li>If sqlite keeps track of the size of the BLOB and length doesn't use it, is the size accessible via some other functionality?</li>
  </ul>
  
  <p>I'm asking this because I'm wondering if I should implement triggers that set BLOBs' sizes in additional columns, of if I can obtain the sizes dynamically without the performance hit of sqlite reading the BLOBs.</p>