Curl connection fails randomly

[Nick-S-2018]

We have an issue with curl connection which looks similar to the one described here.
The client fails while processing multiple requests to the server executed in a loop. The issue can be reproduced with the test script and data attached.

testing.zip
manticore.json

[Nick-S-2018]

This issue can be fixed if Manticore would support HTTP keep-alive connections by default.
The tests showed that if the number of open keep-alive connections exceeds the number the server can currently handle, next attempts of connections from clients just get reset. Elasticsearch demonstrates the same behavior so we can follow their example here.

[Nick-S-2018]

Blocked by manticoresoftware/manticoresearch#3336