user31947: Already found many useful information regarding the chainstats db.
such as:
What are the keys used in the blockchain levelDB (ie what are the key:value pairs)?
But what is the meanning of the last item?
'B' -> 32-byte block hash: the block hash up to which the database represents the unspent transaction outputs.

Is that means there is a row in the db, which key is a constant 'B' and value is the latest block hash?

user208: 
Is that means there is a row in the db, which key is a constant 'B' and value is the latest block hash?

Correct.

31947: <p>Already found many useful information regarding the chainstats db.</p>
<p>such as:
<a href="https://bitcoin.stackexchange.com/questions/28168/what-are-the-keys-used-in-the-blockchain-leveldb-ie-what-are-the-keyvalue-pair">What are the keys used in the blockchain levelDB (ie what are the key:value pairs)?</a></p>
<p>But what is the meanning of the last item?</p>
<pre><code>'B' -&gt; 32-byte block hash: the block hash up to which the database represents the unspent transaction outputs.
</code></pre>
<p>Is that means there is a row in the db, which key is a constant 'B' and value is the latest block hash?</p>
 208: <blockquote>
<p>Is that means there is a row in the db, which key is a constant 'B' and value is the latest block hash?</p>
</blockquote>
<p>Correct.</p>
