Slow response from Thanos behind a proxy

[LukaszSz]

Hi,

From few weeks in my Grafana I experience slow response from Thanos server.

During investigation I noticed that response is ok when I send a query directly to Thanos service:

####################################################

# time curl  "http://127.0.0.1:9090/api/v1/query?query=b_s3_limit"
{"status":"success","data":{"resultType":"vector","result":["value":[1698214769.395,"87960930222080"]}]}}

real  0m0,261s
user 0m0,014s
sys   0m0,004s

####################################################

When I send the same query to Thanos via proxy(nginx) the response time is much,much  longer:

####################################################

# time curl "https://thanos_server.example.com/api/v1/query?query=b_s3_limit"
{"status":"success","data":{"resultType":"vector","result":["value":[1698214761.407,"87960930222080"]}]}}

 

real         0m8,808s
user 0m0,026s
sys         0m0,003s

####################################################

In this case I suspect that nginx has a bad configuration somhow. I checked the query with nginx buffering on|off but with the same result.

Anyone had the similar issue or can help to point me in good direction ? 

Thanos version is 0.26.0

Thanks