Interesting indeed, we did not see anything with VisualVM but having a look at the GC logs could gives us more info, especially on the pauses.
I will collect data over the week-end and look at it. Thanks ________________________________ De : Hullegård, Jimi <jimi.hulleg...@svensktnaringsliv.se> Envoyé : vendredi 11 janvier 2019 03:46:02 À : solr-user@lucene.apache.org Objet : Re: Delayed/waiting requests Could be caused by garbage collection in the jvm. https://wiki.apache.org/solr/SolrPerformanceProblems Go down to the segment called “GC pause problems” /Jimi Sent from my iPhone On 11 Jan 2019, at 05:05, Gael Jourdan-Weil <gael.jourdan-w...@kelkoogroup.com<mailto:gael.jourdan-w...@kelkoogroup.com>> wrote: Hello, We are experiencing some performance issues on a simple SolrCloud cluster of 3 replicas (1 core) but what we found during our analysis seems a bit odd, so we thought the community could have relevant ideas on this. Load: between 30 and 40 queries per second, constant over time of analysis Symptoms: high response time over short period of time but quite frequently. We are talking about requests response time going from 50ms to 5000ms or even worse during less than 5 seconds, and then going back to normal. What we found out: just before response time increase, requests seems to be delayed. That is during 2/3 seconds, requests pile up, no response is sent, and then all requests are resolved and responses are all returned to the clients at the same time. Very much like if there was a lock happening somewhere. But we found no "lock" time nor at JVM or system level. Does someone can think of something that could explain this in the way Solr works ? Or ideas to track down the root cause.. Solr version is 7.2.1. Thanks for reading, Gaël Jourdan-Weil Svenskt Näringsliv behandlar dina personuppgifter i enlighet med GDPR. Här kan du läsa mer om vår behandling och dina rättigheter, Integritetspolicy<https://www.svensktnaringsliv.se/dataskydd/integritet-och-behandling-av-personuppgifter_697219.html?utm_source=sn-email&utm_medium=email>