[GitHub] [apisix] bin-53 commented on issue #7088: bug: Least-connection result is incorrect

["bin-53 (via GitHub)" <gi...@apache.org>]

bin-53 commented on issue #7088:
URL: https://github.com/apache/apisix/issues/7088#issuecomment-1512799061

   > > but from the test result, that is no relation with actice-conn.
   > 
   > I updated case 1
   > 
   > ```
   > use t::APISIX 'no_plan';
   > 
   > repeat_each(2);
   > log_level('info');
   > no_root_location();
   > worker_connections(1024);
   > no_shuffle();
   > 
   > add_block_preprocessor(sub {
   >     my ($block) = @_;
   > 
   >     if (!$block->request) {
   >         $block->set_value("request", "GET /mysleep?seconds=0.1");
   >     }
   > 
   >     if ((!defined $block->error_log) && (!defined $block->no_error_log)) {
   >         $block->set_value("no_error_log", "[error]");
   >     }
   > 
   >     my $http_config = $block->http_config // <<_EOC_;
   >     # fake server, only for test
   >     server {
   >         listen 1970;
   >         location / {
   >             content_by_lua_block {
   >                 ngx.sleep(0.5)
   >                 ngx.say(1970)
   >             }
   >         }
   >     }
   > 
   >     server {
   >         listen 1971;
   >         location / {
   >             content_by_lua_block {
   >                 ngx.sleep(0.5)
   >                 ngx.say(1971)
   >             }
   >         }
   >     }
   > _EOC_
   > 
   >     $block->set_value("http_config", $http_config);
   > });
   > 
   > run_tests();
   > 
   > __DATA__
   > 
   > === TEST 1: same weight
   > --- config
   >     location /t {
   >         content_by_lua_block {
   >             local t = require("lib.test_admin").test
   >             local code, body = t('/apisix/admin/upstreams/1',
   >                  ngx.HTTP_PUT,
   >                  [[{
   >                     "nodes": {
   >                         "127.0.0.1:1970": 1,
   >                         "127.0.0.1:1971": 2
   >                     },
   >                     "type": "least_conn"
   >                 }]]
   >                 )
   > 
   >             if code >= 300 then
   >                 ngx.status = code
   >                 ngx.say(body)
   >             end
   > 
   >             local code, body = t('/apisix/admin/routes/1',
   >                  ngx.HTTP_PUT,
   >                  [[{
   >                         "uri": "/hello",
   >                         "upstream_id": "1"
   >                 }]]
   >                 )
   > 
   >             if code >= 300 then
   >                 ngx.status = code
   >                 ngx.say(body)
   >             end
   > 
   >             local http = require "resty.http"
   >             local uri = "http://127.0.0.1:" .. ngx.var.server_port
   >                         .. "/hello"
   > 
   >             local t = {}
   >             local ports = {}
   >             for i = 1, 3 do
   >                 local th = assert(ngx.thread.spawn(function(i)
   >                     local httpc = http.new()
   >                     local res, err = httpc:request_uri(uri, {method = "GET"})
   >                     if not res then
   >                         ngx.log(ngx.ERR, err)
   >                         return
   >                     end
   >                     local port = tonumber(res.body)
   >                     ports[i] = port
   >                 end, i))
   >             end
   >             for i, th in ipairs(t) do
   >                 ngx.thread.wait(th)
   >             end
   > 
   >             ngx.sleep(1)
   >             ngx.say(table.concat(ports, ", "))
   >         }
   >     }
   > --- request
   > GET /t
   > --- timeout: 15
   > --- response_body
   > 1971, 1971, 1970
   > --- no_error_log
   > [error]
   > ```
   > 
   > > So case 2 is serially or concurrently?
   > 
   > Correction, case 1 sends the request concurrently and case 2 sends it serially. To test `least_conn`, I need to base it on case 1.
   > 
   > Let's discuss case 1 based on the above update : 3 requests will be sent, the` least_conn` will also do 3 rounds of selection
   > 
   > round 1:
   > 
   > 1970 score: 0(active connection) + 1 / 1 (weight) = 1 1971 score: 0(active connection) + 1 / 2 (weight) = 0.5
   > 
   > select score smaller 1971
   > 
   > round 2:
   > 
   > 1970 score: 0(active connection) + 1 / 1 (weight) = 1 1971 score: 1(active connection) + 1 / 2 (weight) = 1
   > 
   > 1971 would be chosen even though the score is the same (not discussing it, which is a separate detail)
   > 
   > round 3:
   > 
   > 1970 score: 0(active connection) + 1 / 1 (weight) = 1 1971 score: 2(active connection) + 1 / 2 (weight) = 1.5
   > 
   > select score smaller 1970
   > 
   > Based on this analysis, I think there is no problem with `least_conn`, and the implementation is also related to active connection.
   > 
   > Note: that the score used above has nothing to do with the `score` in the APISIX implementation code. It's just to explain that `least_conn` works well in your terms.
   
   Please help me with #9325,the least_conn problem,thanks ,sir


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