Recently, we have upgraded elasticsearch to version 5.6, but while using rest client we constantly getting errors listener timeout after waiting for 30000ms, We got the requests from our customer app to search for data in elasticsearch, we are getting request with a rate of 100 req/sec, In the previous version of elasticsearch, transport client was able to manage these requests quite easily but in rest client, we are getting listener timeout exception for many of them. Even after increasing timeout time, we are getting the same error.
By analyzing the code of apache rest client, we had figured out most of the request were waiting in the queue and after 30000ms all requests were rejected, So We tried increasing thread count but it had a very low impact.
Please help over this issue, we need same performance as was in the previous version. Thanks in advance.