Omeka has encountered an error

Zend_Db_Adapter_Mysqli_Exception

Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (111)

exception 'Zend_Db_Adapter_Mysqli_Exception' with message 'Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (111)' in /var/www/clinton_omeka/application/libraries/Zend/Db/Adapter/Mysqli.php:340
Stack trace:
#0 /var/www/clinton_omeka/application/libraries/Zend/Db/Adapter/Abstract.php(316): Zend_Db_Adapter_Mysqli->_connect()
#1 /var/www/clinton_omeka/application/libraries/Omeka/Db.php(87): Zend_Db_Adapter_Abstract->getConnection()
#2 /var/www/clinton_omeka/application/libraries/Omeka/Db/Table.php(648): Omeka_Db->__call('query', Array)
#3 /var/www/clinton_omeka/application/libraries/Omeka/Db/Table.php(648): Omeka_Db->query(Object(Omeka_Db_Select), Array)
#4 /var/www/clinton_omeka/application/models/Table/ElementText.php(44): Omeka_Db_Table->fetchObjects(Object(Omeka_Db_Select))
#5 /var/www/clinton_omeka/application/models/Mixin/ElementText.php(171): Table_ElementText->findByRecord(Object(File))
#6 /var/www/clinton_omeka/application/models/Mixin/ElementText.php(142): Mixin_ElementText->_getElementTextRecords()
#7 /var/www/clinton_omeka/application/models/Mixin/ElementText.php(288): Mixin_ElementText->loadElementsAndTexts()
#8 /var/www/clinton_omeka/application/models/Mixin/ElementText.php(214): Mixin_ElementText->getElement('Dublin Core', 'Title')
#9 /var/www/clinton_omeka/application/models/Mixin/ElementText.php(770): Mixin_ElementText->getElementTexts('Dublin Core', 'Title')
#10 [internal function]: Mixin_ElementText->getDisplayTitle('2016-0984-F Seg...')
#11 /var/www/clinton_omeka/application/libraries/Omeka/Record/AbstractRecord.php(251): call_user_func_array(Array, Array)
#12 /var/www/clinton_omeka/application/libraries/Omeka/Record/AbstractRecord.php(210): Omeka_Record_AbstractRecord->delegateToMixins('getDisplayTitle', Array)
#13 /var/www/clinton_omeka/application/models/File.php(149): Omeka_Record_AbstractRecord->__call('getDisplayTitle', Array)
#14 /var/www/clinton_omeka/application/models/File.php(149): File->getDisplayTitle('2016-0984-F Seg...')
#15 /var/www/clinton_omeka/application/views/helpers/Metadata.php(169): File->getProperty('display_title')
#16 /var/www/clinton_omeka/application/views/helpers/Metadata.php(144): Omeka_View_Helper_Metadata->_getRecordMetadata(Object(File), 'display title')
#17 /var/www/clinton_omeka/application/views/helpers/Metadata.php(73): Omeka_View_Helper_Metadata->_getText(Object(File), 'display title')
#18 [internal function]: Omeka_View_Helper_Metadata->metadata(Object(File), 'display title', Array)
#19 /var/www/clinton_omeka/application/libraries/Zend/View/Abstract.php(350): call_user_func_array(Array, Array)
#20 /var/www/clinton_omeka/application/libraries/globals.php(2038): Zend_View_Abstract->__call('metadata', Array)
#21 /var/www/clinton_omeka/application/libraries/globals.php(2038): Omeka_View->metadata(Object(File), 'display title', Array)
#22 /var/www/clinton_omeka/application/views/helpers/FileMarkup.php(618): metadata(Object(File), 'display title', Array)
#23 /var/www/clinton_omeka/application/libraries/globals.php(2167): Omeka_View_Helper_FileMarkup->image_tag(Object(File), Array, 'square_thumbnai...')
#24 /var/www/clinton_omeka/application/libraries/globals.php(2211): file_image('square_thumbnai...', Array, Object(File))
#25 /var/www/clinton_omeka/plugins/SolrSearch/views/shared/results/index.php(150): item_image_gallery(Array, 'square_thumbnai...', false, Object(Item))
#26 /var/www/clinton_omeka/application/libraries/Omeka/View.php(117): include('/var/www/clinto...')
#27 /var/www/clinton_omeka/application/libraries/Zend/View/Abstract.php(888): Omeka_View->_run('/var/www/clinto...')
#28 /var/www/clinton_omeka/application/libraries/Zend/Controller/Action/Helper/ViewRenderer.php(912): Zend_View_Abstract->render('results/index.p...')
#29 /var/www/clinton_omeka/application/libraries/Zend/Controller/Action/Helper/ViewRenderer.php(933): Zend_Controller_Action_Helper_ViewRenderer->renderScript('results/index.p...', NULL)
#30 /var/www/clinton_omeka/application/libraries/Zend/Controller/Action/Helper/ViewRenderer.php(972): Zend_Controller_Action_Helper_ViewRenderer->render()
#31 /var/www/clinton_omeka/application/libraries/Zend/Controller/Action/HelperBroker.php(277): Zend_Controller_Action_Helper_ViewRenderer->postDispatch()
#32 /var/www/clinton_omeka/application/libraries/Zend/Controller/Action.php(527): Zend_Controller_Action_HelperBroker->notifyPostDispatch()
#33 /var/www/clinton_omeka/application/libraries/Zend/Controller/Dispatcher/Standard.php(308): Zend_Controller_Action->dispatch('indexAction')
#34 /var/www/clinton_omeka/application/libraries/Zend/Controller/Front.php(954): Zend_Controller_Dispatcher_Standard->dispatch(Object(Zend_Controller_Request_Http), Object(Zend_Controller_Response_Http))
#35 /var/www/clinton_omeka/application/libraries/Zend/Application/Bootstrap/Bootstrap.php(105): Zend_Controller_Front->dispatch()
#36 /var/www/clinton_omeka/application/libraries/Zend/Application.php(384): Zend_Application_Bootstrap_Bootstrap->run()
#37 /var/www/clinton_omeka/application/libraries/Omeka/Application.php(77): Zend_Application->run()
#38 /var/www/clinton_omeka/index.php(23): Omeka_Application->run()
#39 {main}