MediaWiki internal error.

Original exception: exception 'DBQueryError' with message 'A database error has occurred
Query: SELECT MAX(rc_timestamp) FROM `wiki_jprecentchanges` LIMIT 1
Function: checkLastModified
Error: 1033 Incorrect information in file: './usr_web4_1/wiki_jprecentchanges.frm' (localhost)
' in /var/www/web4/html/includes/db/Database.php:636
Stack trace:
#0 /var/www/web4/html/includes/db/Database.php(591): Database->reportQueryError('Incorrect infor...', 1033, 'SELECT MAX(rc_...', 'checkLastModifi...', false)
#1 /var/www/web4/html/includes/db/Database.php(1001): Database->query('SELECT MAX(rc_...', 'checkLastModifi...')
#2 /var/www/web4/html/includes/db/Database.php(918): Database->select('recentchanges', 'MAX(rc_timestam...', false, 'checkLastModifi...', Array)
#3 /var/www/web4/html/includes/specials/SpecialRecentchanges.php(177): Database->selectField('recentchanges', 'MAX(rc_timestam...', false, 'checkLastModifi...')
#4 /var/www/web4/html/includes/specials/SpecialRecentchanges.php(86): SpecialRecentChanges->checkLastModified(NULL)
#5 /var/www/web4/html/includes/SpecialPage.php(539): SpecialRecentChanges->execute(NULL)
#6 /var/www/web4/html/includes/Wiki.php(226): SpecialPage::executePath(Object(Title))
#7 /var/www/web4/html/includes/Wiki.php(59): MediaWiki->initializeSpecialCases(Object(Title), Object(OutputPage), Object(WebRequest))
#8 /var/www/web4/html/wiki(114): MediaWiki->initialize(Object(Title), NULL, Object(OutputPage), Object(User), Object(WebRequest))
#9 {main}

Exception caught inside exception handler: exception 'DBUnexpectedError' with message 'Error in fetchObject(): Incorrect information in file: './usr_web4_1/wiki_jppage.frm' (localhost)' in /var/www/web4/html/includes/db/Database.php:763
Stack trace:
#0 /var/www/web4/html/includes/MessageCache.php(340): Database->fetchObject(false)
#1 /var/www/web4/html/includes/MessageCache.php(268): MessageCache->loadFromDB('ja')
#2 /var/www/web4/html/includes/MessageCache.php(589): MessageCache->load('ja')
#3 /var/www/web4/html/includes/MessageCache.php(526): MessageCache->getMsgFromNamespace('Databaseerror', 'ja')
#4 /var/www/web4/html/includes/GlobalFunctions.php(583): MessageCache->get('databaseerror', true, false)
#5 /var/www/web4/html/includes/GlobalFunctions.php(548): wfMsgGetKey('databaseerror', true, false, true)
#6 /var/www/web4/html/includes/Exception.php(70): wfMsgReal('databaseerror', Array)
#7 /var/www/web4/html/includes/db/Database.php(2617): MWException->msg('databaseerror', 'Database error')
#8 /var/www/web4/html/includes/Exception.php(201): DBQueryError->getPageTitle()
#9 /var/www/web4/html/includes/Exception.php(164): MWException->htmlHeader()
#10 /var/www/web4/html/includes/Exception.php(183): MWException->reportHTML()
#11 /var/www/web4/html/includes/Exception.php(269): MWException->report()
#12 /var/www/web4/html/includes/Exception.php(327): wfReportException(Object(DBQueryError))
#13 [internal function]: wfExceptionHandler(Object(DBQueryError))
#14 {main}