PDOException: PDO::__construct(): Error while reading greeting packet. PID=76686 in /var/www/wiki/html/lib/semantics.php:45
Stack trace:
#0 /var/www/wiki/html/lib/semantics.php(45): PDO->__construct()
#1 /var/www/wiki/html/lib/semantics.php(102): PluginSemantics->__construct()
#2 /var/www/wiki/html/plugin/property.inc.php(468): require_once('/var/www/wiki/h...')
#3 /var/www/wiki/html/lib/plugin.php(43): require_once('/var/www/wiki/h...')
#4 /var/www/wiki/html/lib/plugin.php(79): exist_plugin()
#5 /var/www/wiki/html/lib/make_link.php(298): exist_plugin_inline()
#6 /var/www/wiki/html/lib/make_link.php(136): Link_plugin->toString()
#7 [internal function]: InlineConverter->replace()
#8 /var/www/wiki/html/lib/make_link.php(121): preg_replace_callback()
#9 /var/www/wiki/html/lib/make_link.php(38): InlineConverter->convert()
#10 /var/www/wiki/html/lib/convert_html.php(180): make_link()
#11 /var/www/wiki/html/lib/convert_html.php(106): Inline->__construct()
#12 /var/www/wiki/html/lib/convert_html.php(980): Factory_Inline()
#13 /var/www/wiki/html/lib/convert_html.php(23): Body->parse()
#14 /var/www/wiki/html/lib/pukiwiki.php(107): convert_html()
#15 /var/www/wiki/html/index.php(23): require('/var/www/wiki/h...')
#16 {main}

Next PDOException: SQLSTATE[HY000] [2006] MySQL server has gone away in /var/www/wiki/html/lib/semantics.php:45
Stack trace:
#0 /var/www/wiki/html/lib/semantics.php(45): PDO->__construct()
#1 /var/www/wiki/html/lib/semantics.php(102): PluginSemantics->__construct()
#2 /var/www/wiki/html/plugin/property.inc.php(468): require_once('/var/www/wiki/h...')
#3 /var/www/wiki/html/lib/plugin.php(43): require_once('/var/www/wiki/h...')
#4 /var/www/wiki/html/lib/plugin.php(79): exist_plugin()
#5 /var/www/wiki/html/lib/make_link.php(298): exist_plugin_inline()
#6 /var/www/wiki/html/lib/make_link.php(136): Link_plugin->toString()
#7 [internal function]: InlineConverter->replace()
#8 /var/www/wiki/html/lib/make_link.php(121): preg_replace_callback()
#9 /var/www/wiki/html/lib/make_link.php(38): InlineConverter->convert()
#10 /var/www/wiki/html/lib/convert_html.php(180): make_link()
#11 /var/www/wiki/html/lib/convert_html.php(106): Inline->__construct()
#12 /var/www/wiki/html/lib/convert_html.php(980): Factory_Inline()
#13 /var/www/wiki/html/lib/convert_html.php(23): Body->parse()
#14 /var/www/wiki/html/lib/pukiwiki.php(107): convert_html()
#15 /var/www/wiki/html/index.php(23): require('/var/www/wiki/h...')
#16 {main}データベースに接続できませんでした。\n2456