title: Why LMDB database taking more than actual data size?
body: <p>I put around 11K key&amp;values in LMDB database . 
  LMDB database file size become 21Mb.</p>
  
  <p>For the same data the leveldb is taking 8Mb only (with snappy compression).</p>
  
  <p>LMDB env info ,</p>
  
  <pre><code>VERSION=3
  format=bytevalue
  type=btree
  mapsize=1073741824
  maxreaders=126
  db_pagesize=4096
  </code></pre>
  
  <p>TO check why LMDB file size is more ,I iterated through all keys &amp; values inside
  the database. The total size of all key &amp; value is 10Mb. </p>
  
  <p>But the actual size of the file is 21Mb. 
  Remaining file size of 11Mb  (21Mb - 10Mb) used for what purpose???!!.</p>
  
  <p>If i compress data before put operation ,only 2Mb got reduced</p>
  
  <p>Why LMDB database file size is more than actual data size?</p>
  
  <p>Any way to shrink it ?</p>