# ES-5x : JsonGenerationException in slow logs **URL:** \ **Category:** Elasticsearch\ **Created:** [November 21, 2017, 5:20am UTC](https://discuss.elastic.co/t/es-5x-jsongenerationexception-in-slow-logs/108510 "2017-11-21T05:20:15Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![dimalini](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/dimalini/32/22448_2.png) [@dimalini](https://discuss.elastic.co/u/dimalini)\ **Post date:** [November 21, 2017, 5:20am UTC](https://discuss.elastic.co/t/es-5x-jsongenerationexception-in-slow-logs/108510/1 "2017-11-21T05:20:15Z")
Hi, As part of slow query investigation, we enabled search slow logs in our production environment[ES version - 5.4.1]. In few cases, i do see the original slow query getting logged. But there were many occurrences of JsonGenerationException as seen below. Could someone help understand the cases when we would encounter this? > [2017-11-20T11:35:32,917][WARN][index.search.slowlog.query] [es-d11-rm] [sharedindex][10] took[12.5s], took\_millis[12544], types[documentcontract], stats, search\_type[QUERY\_THEN\_FETCH], total\_shards[6], source[{ **"error" : "JsonGenerationException[Can not start an object, expecting field name (context: Object)]"}]**, > [2017-11-20T11:35:42,521][WARN][index.search.slowlog.query] [es-d11-rm] [sharedindex][3] took[22.1s], took\_millis[22158], types[documentcontract], stats, search\_type[QUERY\_THEN\_FETCH], total\_shards[6], source[{ "error" : "JsonGenerationException[Can not start an object, expecting field name (context: Object)]"}], > [2017-11-20T11:47:26,846][INFO][index.search.slowlog.query] [es-d11-rm] [sharedindex][3] took[6.3s], took\_millis[6330], types[documentcontract], stats, search\_type[QUERY\_THEN\_FETCH], total\_shards[6], source[{ "error" : "JsonGenerationException[Can not start an object, expecting field name (context: Object)]"}], > [2017-11-20T11:48:27,842][INFO][index.search.slowlog.query] [es-d11-rm] [sharedindex][3] took[6.9s], took\_millis[6932], types[documentcontract], stats, search\_type[QUERY\_THEN\_FETCH], total\_shards[6], source[{ "error" : "JsonGenerationException[Can not start an object, expecting field name (context: Object)]"}], > [2017-11-20T11:48:45,656][INFO][index.search.slowlog.query] [es-d11-rm] [sharedindex][6] took[9.1s], took\_millis[9168], types[documentcontract], stats, search\_type[QUERY\_THEN\_FETCH], total\_shards[6], source[{ "error" : "JsonGenerationException[Can not start an object, expecting field name (context: Object)]"}], > [2017-11-20T11:48:57,620][WARN][index.search.slowlog.query] [es-d11-rm] [sharedindex][9] took[21.1s], took\_millis[21121], types[documentcontract], stats, search\_type[QUERY\_THEN\_FETCH], total\_shards[6], source[{ "error" : "JsonGenerationException[Can not start an object, expecting field name (context: Object)]"}], > [2017-11-20T11:49:08,569][WARN][index.search.slowlog.query] [es-d11-rm] [sharedindex][2] took[32s], took\_millis[32080], types[documentcontract], stats, search\_type[QUERY\_THEN\_FETCH], total\_shards[6], source[{ "error" : "JsonGenerationException[Can not start an object, expecting field name (context: Object)]"}], > [2017-11-20T11:50:59,729][INFO][index.search.slowlog.query] [es-d11-rm] [sharedindex][3] took[6.8s], took\_millis[6898], types[documentcontract], stats, search\_type[QUERY\_THEN\_FETCH], total\_shards[6], source[{ "error" : "JsonGenerationException[Can not start an object, expecting field name (context: Object)]"}], > [2017-11-20T11:56:02,530][WARN][index.search.slowlog.query] [es-d11-rm] [sharedindex][9] took[10.1s], took\_millis[10146], types[documentcontract], stats, search\_type[QUERY\_THEN\_FETCH], total\_shards[6], source[{ "error" : "JsonGenerationException[Can not start an object, expecting field name (context: Object)]"}], > [2017-11-20T11:56:05,265][WARN][index.search.slowlog.query] [es-d11-rm] [sharedindex][2] took[12.8s], took\_millis[12872], types[documentcontract], stats, search\_type[QUERY\_THEN\_FETCH], total\_shards[6], source[{ "error" : "JsonGenerationException[Can not start an object, expecting field name (context: Object)]"}], > [2017-11-20T11:56:17,629][WARN][index.search.slowlog.query] [es-d11-rm] [sharedindex][3] took[25.2s], took\_millis[25239], types[documentcontract], stats, search\_type[QUERY\_THEN\_FETCH], total\_shards[6], source[{ "error" : "JsonGenerationException[Can not start an object, expecting field name (context: Object)]"}], > [2017-11-20T11:56:17,629][WARN][index.search.slowlog.query] [es-d11-rm] [sharedindex][3] took[10.7s], took\_millis[10724], types[documentcontract], stats, search\_type[QUERY\_THEN\_FETCH], total\_shards[6], source[{ "error" : "JsonGenerationException[Can not start an object, expecting field name (context: Object)]"}], > [2017-11-20T11:56:25,755][INFO][index.search.slowlog.query] [es-d11-rm] [sharedindex][10] took[5.3s], took\_millis[5360], types[documentcontract], stats, search\_type[QUERY\_THEN\_FETCH], total\_shards[6], source[{ "error" : "JsonGenerationException[Can not start an object, expecting field name (context: Object)]"}], > [2017-11-20T12:08:41,808][WARN][index.search.slowlog.query] [es-d11-rm] [sharedindex][2] took[16.2s], took\_millis[16216], types[documentcontract], stats, search\_type[QUERY\_THEN\_FETCH], total\_shards[6], source[{ "error" : "JsonGenerationException[Can not start an object, expecting field name (context: Object)]"}], > [2017-11-20T12:08:47,168][WARN][index.search.slowlog.query] [es-d11-rm] [sharedindex][9] took[21.5s], took\_millis[21578], types[documentcontract], stats, search\_type[QUERY\_THEN\_FETCH], total\_shards[6], source[{ "error" : "JsonGenerationException[Can not start an object, expecting field name (context: Object)]"}], > [2017-11-20T12:08:58,130][INFO][index.search.slowlog.query] [es-d11-rm] [sharedindex][3] took[5.3s], took\_millis[5330], types[documentcontract], stats, search\_type[QUERY\_THEN\_FETCH], total\_shards[6], source[{ "error" : "JsonGenerationException[Can not start an object, expecting field name (context: Object)]"}] Thanks, Divya Malini ---
**Author:** ![jpountz](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/jpountz/32/45836_2.png) [@jpountz](https://discuss.elastic.co/u/jpountz)\ **Post date:** [November 21, 2017, 1:46pm UTC](https://discuss.elastic.co/t/es-5x-jsongenerationexception-in-slow-logs/108510/2 "2017-11-21T13:46:41Z")
This looks like a bug. By any chance, would you be able to find one query that triggers this bug? It would help identify it and then fix it. ---
**Author:** ![dimalini](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/dimalini/32/22448_2.png) [@dimalini](https://discuss.elastic.co/u/dimalini)\ **Post date:** [November 22, 2017, 1:19am UTC](https://discuss.elastic.co/t/es-5x-jsongenerationexception-in-slow-logs/108510/3 "2017-11-22T01:19:32Z")
I enabled the logs to get the actual query. Anyway i ll try to get the query and share, even otherwise could you please take a look ? ---
**Author:** ![dimalini](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/dimalini/32/22448_2.png) [@dimalini](https://discuss.elastic.co/u/dimalini)\ **Post date:** [November 27, 2017, 10:28am UTC](https://discuss.elastic.co/t/es-5x-jsongenerationexception-in-slow-logs/108510/4 "2017-11-27T10:28:51Z")
Hi Adrien, I am unable to get the original query yet. Could the number of chars in the request contribute to this exception? Our request would easily exceed 32767 in some cases, if this would help you narrow to the bug causing this exception. Thanks, Divya ---
**Author:** ![dimalini](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/dimalini/32/22448_2.png) [@dimalini](https://discuss.elastic.co/u/dimalini)\ **Post date:** [November 29, 2017, 6:09pm UTC](https://discuss.elastic.co/t/es-5x-jsongenerationexception-in-slow-logs/108510/5 "2017-11-29T18:09:01Z")
Any help here? I was expecting to get the original query by enabling the slow logs. But I am constantly getting this exception. To add details - we are in NEST 2.x and ES 5.4.1 ---
**Author:** ![dimalini](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/dimalini/32/22448_2.png) [@dimalini](https://discuss.elastic.co/u/dimalini)\ **Post date:** [November 30, 2017, 10:08am UTC](https://discuss.elastic.co/t/es-5x-jsongenerationexception-in-slow-logs/108510/6 "2017-11-30T10:08:00Z")
I did the following to reproduce the exception locally. Had the search slow logs settings as follows > PUT \_all/\_settings > { > "index.search.slowlog.threshold.query.warn": "1ms", > "index.search.slowlog.threshold.query.info": "1ms", > "index.search.slowlog.threshold.fetch.warn": "1ms", > "index.search.slowlog.threshold.fetch.info": "1ms" > } And executed a sample query that mimics our actual query. Please find the query below > ---
**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\ **Post date:** [December 28, 2017, 10:18am UTC](https://discuss.elastic.co/t/es-5x-jsongenerationexception-in-slow-logs/108510/7 "2017-12-28T10:18:58Z")
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