MediaWiki API result

This is the HTML representation of the JSON format. HTML is good for debugging, but is unsuitable for application use.
Specify the format parameter to change the output format. To see the non-HTML representation of the JSON format, set format=json.
See the complete documentation, or the API help for more information.
This response would be returned with HTTP status 1213 .
{
    "batchcomplete": "",
    "query": {
        "pages": {
            "1": {
                "pageid": 1,
                "ns": 0,
                "title": "Main Page",
                "templates": [
                    {
                        "ns": 0,
                        "title": "Kex"
                    },
                    {
                        "ns": 0,
                        "title": "KexAB"
                    },
                    {
                        "ns": 0,
                        "title": "PA"
                    },
                    {
                        "ns": 10,
                        "title": "Template:Extension DPL"
                    },
                    {
                        "ns": 10,
                        "title": "Template:Infobox"
                    },
                    {
                        "ns": 10,
                        "title": "Template:Infobox model parameter"
                    },
                    {
                        "ns": 10,
                        "title": "Template:Lowercase title"
                    },
                    {
                        "ns": 828,
                        "title": "Module:Infobox"
                    },
                    {
                        "ns": 828,
                        "title": "Module:Navbar"
                    }
                ]
            }
        }
    }
}{
    "error": {
        "code": "internal_api_error_mysqli_sql_exception",
        "info": "[aYeum5m6Nej6el2agkNzAgAAABI] Exception caught: Deadlock found when trying to get lock; try restarting transaction",
        "errorclass": "mysqli_sql_exception",
        "*": "mysqli_sql_exception at /home/project-web/nmr-relax/htdocs/wiki/includes/libs/rdbms/database/DatabaseMysqli.php(46)\n#0 /home/project-web/nmr-relax/htdocs/wiki/includes/libs/rdbms/database/DatabaseMysqli.php(46): mysqli->query(string)\n#1 /home/project-web/nmr-relax/htdocs/wiki/includes/libs/rdbms/database/Database.php(1327): Wikimedia\\Rdbms\\DatabaseMysqli->doQuery(string)\n#2 /home/project-web/nmr-relax/htdocs/wiki/includes/libs/rdbms/database/Database.php(1229): Wikimedia\\Rdbms\\Database->attemptQuery(string, string, boolean, string)\n#3 /home/project-web/nmr-relax/htdocs/wiki/includes/libs/rdbms/database/Database.php(2154): Wikimedia\\Rdbms\\Database->query(string, string)\n#4 /home/project-web/nmr-relax/htdocs/wiki/includes/objectcache/SqlBagOStuff.php(376): Wikimedia\\Rdbms\\Database->insert(string, array, string, string)\n#5 /home/project-web/nmr-relax/htdocs/wiki/includes/objectcache/SqlBagOStuff.php(401): SqlBagOStuff->insertMulti(array, integer, integer, boolean)\n#6 /home/project-web/nmr-relax/htdocs/wiki/includes/libs/objectcache/BagOStuff.php(422): SqlBagOStuff->add(string, integer, integer)\n#7 [internal function]: BagOStuff->{closure}()\n#8 /home/project-web/nmr-relax/htdocs/wiki/vendor/wikimedia/wait-condition-loop/src/WaitConditionLoop.php(92): call_user_func(Closure)\n#9 /home/project-web/nmr-relax/htdocs/wiki/includes/libs/objectcache/BagOStuff.php(438): Wikimedia\\WaitConditionLoop->invoke()\n#10 /home/project-web/nmr-relax/htdocs/wiki/includes/libs/objectcache/BagOStuff.php(495): BagOStuff->lock(string, integer, integer, string)\n#11 /home/project-web/nmr-relax/htdocs/wiki/includes/cache/MessageCache.php(832): BagOStuff->getScopedLock(string, integer, integer, string)\n#12 /home/project-web/nmr-relax/htdocs/wiki/includes/cache/MessageCache.php(433): MessageCache->getReentrantScopedLock(string, integer)\n#13 /home/project-web/nmr-relax/htdocs/wiki/includes/cache/MessageCache.php(359): MessageCache->loadFromDBWithLock(string, array, NULL)\n#14 /home/project-web/nmr-relax/htdocs/wiki/includes/cache/MessageCache.php(1050): MessageCache->load(string)\n#15 /home/project-web/nmr-relax/htdocs/wiki/includes/cache/MessageCache.php(975): MessageCache->getMsgFromNamespace(string, string)\n#16 /home/project-web/nmr-relax/htdocs/wiki/includes/cache/MessageCache.php(947): MessageCache->getMessageForLang(LanguageEn, string, boolean, array)\n#17 /home/project-web/nmr-relax/htdocs/wiki/includes/cache/MessageCache.php(886): MessageCache->getMessageFromFallbackChain(LanguageEn, string, boolean)\n#18 /home/project-web/nmr-relax/htdocs/wiki/includes/Message.php(1308): MessageCache->get(string, boolean, LanguageEn)\n#19 /home/project-web/nmr-relax/htdocs/wiki/includes/Message.php(863): Message->fetchMessage()\n#20 /home/project-web/nmr-relax/htdocs/wiki/includes/Message.php(955): Message->toString(string)\n#21 /home/project-web/nmr-relax/htdocs/wiki/includes/OutputPage.php(940): Message->text()\n#22 /home/project-web/nmr-relax/htdocs/wiki/includes/api/ApiFormatBase.php(255): OutputPage->setPageTitle(Message)\n#23 /home/project-web/nmr-relax/htdocs/wiki/includes/api/ApiMain.php(1850): ApiFormatBase->closePrinter()\n#24 /home/project-web/nmr-relax/htdocs/wiki/includes/api/ApiMain.php(1601): ApiMain->printResult()\n#25 /home/project-web/nmr-relax/htdocs/wiki/includes/api/ApiMain.php(531): ApiMain->executeAction()\n#26 /home/project-web/nmr-relax/htdocs/wiki/includes/api/ApiMain.php(502): ApiMain->executeActionWithErrorHandling()\n#27 /home/project-web/nmr-relax/htdocs/wiki/api.php(87): ApiMain->execute()\n#28 {main}"
    }
}