nginx http2 pictures timeout

[Valentin V. Bartenev]

On Thursday 17 March 2016 07:04:11 meteor8488 wrote:
> Hi All,
> 
> After I upgrade nginx to 1.9.12 and enabled http2 for my website. I found a
> wired issue related with download pictures.
> 
> My website is a photo-sharing websites. So on each page there are about
> 100-200 pictures, the size of each of them may from 10K to 500K.
> 
> In the past (http and https with spdy), I'm using below settings:
> 
> 	client_body_timeout   10;
> 	client_header_timeout 10;
> 	keepalive_timeout     30;
> 	send_timeout          30;
> 
> 	keepalive_requests 200;
> 	keepalive_disable        none;
>  	reset_timedout_connection  on;
> 
> And everything is good. For users from different countries, they can view
> the pictures without any error.
> 
> But after I upgrade to http2, with the same settings, it seems for users who
> have a good bandwidth, everything is fine. But for users who are from
> different countries, some of them experience issue that on the webpage some
> pictures can't display properly. And if they refresh the webpage for 1 times
> or more, then the whole webpage can display as normal, all pictures are
> downloaded and display.
> 
> 
> I tried to change send_timeout value from 30s to 300s, then it seems it can
> fix the problem. I used firefox to monitor the webpage load speed, I can see
> for the pictures of the webpage, the waiting time is pretty long, sometimes
> it's more than 60s - 120s, and then firefox start to receiving the
> pictures.
> 
> My understanding is that after enable http2, nginx are using "Multiplexing
> and concurrency" to send out pictures, which mean for the webpage with 200
> pictures, the web browser is ready to receive all pictures when the
> connections is established.  But for clients who has limited network
> bandwidth to the server, they can only download the pictures slowly. And
> then some of the pictures will be timeout and can't display.
> 
> So, is there any better solution to fix this kind of issue?
> 
[..]

You can try to lower concurrency in HTTP/2 connection.

See the "http2_max_concurrent_streams" directive:
http://nginx.org/r/http2_max_concurrent_streams

  wbr, Valentin V. Bartenev