mORMot Open Source

salah eddine frigini

Member

Registered: 2024-10-12

Posts: 5

i have ian issue with concurrent calls to a function in SOA

The function in the SOA is defined as follows:

function server.functiontotest: string;
var
  g: Integer;  
  ResultStr: string;
begin
  g := 0;
  ResultStr := '';
  while g < 40000 do
  begin
    ResultStr := ResultStr + IntToStr(g);  
    Inc(g);  // Increment g
  end;
  Result := ResultStr;  
end;

The function takes time to return a result. When I call the function with 2 or 3 clients, it returns the result successfully. However, when I call it more than 4 times, I always get a timeout error. Additionally, I am using sicShared for the SOA. Even when I try changing to sicPerThread, I still encounter the same problem.

ab

Administrator

From: France

Registered: 2010-06-21

Posts: 14,657

Website

Re: i have ian issue with concurrent calls to a function in SOA

Which compiler?
Which OS?
How many CPU cores?

My guess is that you only have 4 processing threads (i.e. 4 threads in your HTTP connection), so you get a timeout once all threads are busy.

For such huge process, you need a dedicated thread. Do not pollute the HTTP threads with slow process.
This is why we created the interface based service callbacks, to notify the client once a process is finished, without blocking the HTTP threads.

salah eddine frigini

Member

Registered: 2024-10-12

Posts: 5

Re: i have ian issue with concurrent calls to a function in SOA

I'am working with Windows 10 in virtual machine using Delphi 12.0 Athens / C++Builder 12.0 Athens, product version of 23.0.

CPU : Common KVM processor: 2.10 GHz with 2 cores , 2 sockets  and  mormot 2.2

Last edited by salah eddine frigini (2024-10-24 15:47:21)

ab

Administrator

From: France

Registered: 2010-06-21

Posts: 14,657

Website

Re: i have ian issue with concurrent calls to a function in SOA

So my previous answer is right: you need a dedicated threads for such slow process.

salah eddine frigini

Member

Registered: 2024-10-12

Posts: 5

Re: i have ian issue with concurrent calls to a function in SOA

I am using sicPerThread with a thread pool size of 32 and useHttpSocket. Each time I call the function, the server uses one thread to execute it. I called the function four times, and I have 32 threads in the pool. I don't know why I am experiencing a timeout.

  // creation of the server
  TSQLRestServerDB.Create(HttpPort, [tsimpleserver], '+', useHttpSocket);//32 in the thread pool by default

constructor tsimpleserver.Create(aModel: TORMModel; aDBFILENAME: TFileName);
begin
  inherited Create(aModel, aDBFILENAME); 
  ServiceDefine(TemployeeService, [IEmpService], sicPerThread); 
end;

salah eddine frigini

Member

Registered: 2024-10-12

Posts: 5

Re: i have ian issue with concurrent calls to a function in SOA

When I change the number of iterations in the function from 40,000 to 30,000, I can call the function 6 times concurrently. However, when I try to call it 7 times concurrently, they all give me a timeout.

zen010101

Member

Registered: 2024-06-15

Posts: 66

Re: i have ian issue with concurrent calls to a function in SOA

Theoretically, the execution speed of your service code should not be very slow, and it should not hinder or block the processing thread of the HTTP request. Moreover, even if it does get blocked, for example, you could replace the service code with Sleep(10000), but by default, the thread pool handling requests has 32 work-threads, so it shouldn't block the client's service calls. It's really strange. Could you provide some logs to see what the server-side WebSocket is doing?

salah eddine frigini

Member

Registered: 2024-10-12

Posts: 5

Re: i have ian issue with concurrent calls to a function in SOA

//My server initiates 32 threads after it calls root/timestamp and root/EmpService._contract_.

//Then, it calls the function TestThread.

Interface Post: root/EmpService.TestThread = 200 out, 20 B in, 28.67 s
mormot.rest.server.TrestServerRoutingRest(03fe3880) {"result":["30000"]}
28.678.115

Interface Post: root/EmpService.TestThread = 200 out, 20 B in, 32.76 s
mormot.rest.server.TrestServerRoutingRest(03fe3580) {"result":["30000"]}
32.769.536

Interface Post: root/EmpService.TestThread = 200 out, 20 B in, 32.13 s
mormot.rest.server.TrestServerRoutingRest(03fe3b80) {"result":["30000"]}
32.134.841

Interface Post: root/EmpService.TestThread = 200 out, 20 B in, 32.20 s
mormot.rest.server.TrestServerRoutingRest(03fe3a00) {"result":["30000"]}
32.208.935

Interface Post: root/EmpService.TestThread = 200 out, 20 B in, 31.77 s
mormot.rest.server.TrestServerRoutingRest(03fe3e80) {"result":["30000"]}
32.780.074

Interface Post: root/EmpService.TestThread = 200 out, 20 B in, 33.57 s
mormot.rest.server.TrestServerRoutingRest(03fe3d00) {"result":["30000"]}
32.582.705

trace unit6.TsimpleServer(039b86c0) End current thread (THttpServerResp) Thread ID=1390 'Httpsrv 11111 root ThttpsrvResp' thread count = 6
trace unit6.TsimpleServer(039b86c0) End current thread (THttpServerResp) Thread ID=02a8 'Httpsrv 11111 root ThttpsrvResp' thread count = 5
trace unit6.TsimpleServer(039b86c0) End current thread (THttpServerResp) Thread ID=88 'Httpsrv 11111 root ThttpsrvResp' thread count = 4
trace unit6.TsimpleServer(039b86c0) End current thread (THttpServerResp) Thread ID=13a4 'Httpsrv 11111 root ThttpsrvResp' thread count = 3
trace unit6.TsimpleServer(039b86c0) End current thread (THttpServerResp) Thread ID=1de4 'Httpsrv 11111 root ThttpsrvResp' thread count = 2
trace unit6.TsimpleServer(039b86c0) End current thread (THttpServerResp) Thread ID=1de4 'Httpsrv 11111 root ThttpsrvResp' thread count = 1

The server always returns a result, but in the console of my test, I get a timeout error if I call the function more than six times. If I call it fewer than six times, I receive the result in the test console.

I can also call the function concurrently more than six times and receive the result in the test console, but I have to increase the number of iterations from 30,000 to less than 20,000.

this is the erreur in the test console  :
EXC EInterfaceFactory {Message: "TInterfacedObjectFakeClient.FakeCall(IEmpService.TestThread) failed: 'URI root/IEmpService.TestThread [] return status 'Request Timeout' (408)"} [main] at 7a526d

ttomas

Member

Registered: 2013-03-08

Posts: 135

Re: i have ian issue with concurrent calls to a function in SOA

Log shows you have 6 working threads, not 32! Execution time is >30sec, default timeout is 10sec if I remember.

Last edited by ttomas (2024-10-28 12:02:36)

zen010101

Member

Registered: 2024-06-15

Posts: 66

Re: i have ian issue with concurrent calls to a function in SOA

"but in the console of my test, I get a timeout error if I call the function more than six times

What does this sentence mean?
Is there any difference between the so-called "console of my test" and "///then, it calls the function TestThread"?
In "console of my test", did you also initiate the test using thread concurrency?

My suggestions are:

Server Side:
1. Output the `YourRestHttpServer.HttpServer.HttpQueueLength` property
2. Output the `TWebSocketServerRest(YourRestHttpServer.HttpServer).ThreadPool.WorkThreadCount` property (or using THttpServer(YourRestHttpServer.HttpServer).ThreadPool....)

Client Side:
1. Set global variable `HTTP_DEFAULT_RECEIVETIMEOUT := 120000`
2. Set  `YourRestHttpClientWebsockets.RetryOnceOnTimeout  := true`