Additional uncaught exception thrown while handling exception.

<h1>Additional uncaught exception thrown while handling exception.</h1><h2>Original</h2><p>PDOException: SQLSTATE[HY000]: General error: 2013 Lost connection to MySQL server during query: SELECT revision.vid AS vid, base.uid AS uid, revision.title AS title, revision.log AS log, revision.status AS status, revision.comment AS comment, revision.promote AS promote, revision.sticky AS sticky, revision.vuuid AS vuuid, base.nid AS nid, base.type AS type, base.language AS language, base.created AS created, base.changed AS changed, base.tnid AS tnid, base.translate AS translate, base.uuid AS uuid, revision.timestamp AS revision_timestamp, revision.uid AS revision_uid
FROM 
{node} base
INNER JOIN {node_revision} revision ON revision.nid = base.nid AND revision.vid = :revisionId
WHERE  (base.nid IN  (:db_condition_placeholder_0)) ; Array
(
    [:db_condition_placeholder_0] =&amp;gt; 751
    [:revisionId] =&amp;gt; 211879
)
 in DrupalDefaultEntityController-&gt;load() (line 198 of /var/www/2.0/includes/entity.inc).</p><h2>Additional</h2><p>PDOException: SQLSTATE[HY000]: General error: 2006 MySQL server has gone away: SELECT expire, value FROM {semaphore} WHERE name = :name; Array
(
    [:name] =&amp;gt; rules_get_cacherules_event_whitelist
)
 in lock_may_be_available() (line 167 of /var/www/2.0/includes/lock.inc).</p><hr /><h1>Uncaught exception thrown in shutdown function.</h1><p>PDOException: SQLSTATE[HY000]: General error: 2006 MySQL server has gone away: DELETE FROM {semaphore} 
WHERE  (value = :db_condition_placeholder_0) ; Array
(
    [:db_condition_placeholder_0] =&amp;gt; 6518407016a7ce0e791f1d1.85945582
)
 in lock_release_all() (line 269 of /var/www/2.0/includes/lock.inc).</p><hr />