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: 2006 MySQL server has gone away: SELECT expire, value FROM {semaphore} WHERE name = :name; Array
(
    [:name] =&amp;gt; locale_cache_it
)
 in lock_may_be_available() (line 167 of /web/www/pra/includes/lock.inc).</p><h2>Additional</h2><p>PDOException: SQLSTATE[HY000]: General error: 2006 MySQL server has gone away: INSERT INTO {watchdog} (uid, type, message, variables, severity, link, location, referer, hostname, timestamp) VALUES (:db_insert_placeholder_0, :db_insert_placeholder_1, :db_insert_placeholder_2, :db_insert_placeholder_3, :db_insert_placeholder_4, :db_insert_placeholder_5, :db_insert_placeholder_6, :db_insert_placeholder_7, :db_insert_placeholder_8, :db_insert_placeholder_9); Array
(
    [:db_insert_placeholder_0] =&amp;gt; 0
    [:db_insert_placeholder_1] =&amp;gt; php
    [:db_insert_placeholder_2] =&amp;gt; %type: !message in %function (line %line of %file).
    [:db_insert_placeholder_3] =&amp;gt; a:6:{s:5:&amp;quot;%type&amp;quot;;s:12:&amp;quot;PDOException&amp;quot;;s:8:&amp;quot;!message&amp;quot;;s:167:&amp;quot;SQLSTATE[HY000]: General error: 2006 MySQL server has gone away: SELECT expire, value FROM {semaphore} WHERE name = :name; Array
(
    [:name] =&amp;amp;gt; locale_cache_it
)
&amp;quot;;s:9:&amp;quot;%function&amp;quot;;s:23:&amp;quot;lock_may_be_available()&amp;quot;;s:5:&amp;quot;%file&amp;quot;;s:30:&amp;quot;/web/www/pra/includes/lock.inc&amp;quot;;s:5:&amp;quot;%line&amp;quot;;i:167;s:14:&amp;quot;severity_level&amp;quot;;i:3;}
    [:db_insert_placeholder_4] =&amp;gt; 3
    [:db_insert_placeholder_5] =&amp;gt; 
    [:db_insert_placeholder_6] =&amp;gt; https://pralab.diee.unica.it/it/biblio/export/bibtex/637
    [:db_insert_placeholder_7] =&amp;gt; 
    [:db_insert_placeholder_8] =&amp;gt; 192.168.1.6
    [:db_insert_placeholder_9] =&amp;gt; 1679347201
)
 in dblog_watchdog() (line 160 of /web/www/pra/modules/dblog/dblog.module).</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; 10764913556418ce0153ec24.71085431
)
 in lock_release_all() (line 269 of /web/www/pra/includes/lock.inc).</p><hr />