Feed/csvexport.json deeply slow

Hello everybody

I’m using emoncms on a debian server (vm), on arm64 arch (not a pi). emon stable 10.2.2
my VM has 1.65 Go of RAM. 1 CPU

I have about 10 feeds, phptimeseries, 1 years of data :

  • 5 feeds with 30’ data
  • 5 feeds with daily data

When i do this request :
feed/csvexport.json?id=120&start=1586118600&end=1586727000&timeformat=1&interval=1
so about 350 datas, the server need more than 30 secondes and i have a php timeout after 165 datas

… is it normal ?
when i do a “top”, apache is at 95% all the time of the request

when i use “graph” module, it works perfecly, no problem

thanks