A question about Server Socket !

[skinkairewalker]

Hello everyone, I would like to know how the server acts in multiconnections: When 2 users connect to a socket server and send a text message: "Login: USERNAME: PASSWORD", server receive both messages, the first connected and sent to message runs the functions first, and the second waits in the queue until the server runs?

[infratec]

A server uses threads.

[skinkairewalker]

A server uses threads.

so if I want to initialize a mysql connection for each data request, I should do this:

Code: Select all

 SEvent = NetworkServerEvent()
  
    If SEvent
    
      ClientID = EventClient()
  
      Select SEvent

        Case #PB_NetworkEvent_Data
          ConsoleColor(14,0)
          PrintN("New Message From ["+Str(ClientID)+"]")
          ReceiveNetworkData(ClientID, *RcvMsg, 1000)
          PrintN("Received Msg : "+PeekS(*RcvMsg, -1, #PB_UTF8))
          RcvMsg = PeekS(*RcvMsg, -1, #PB_UTF8)
          FillMemory(*RcvMsg,65536)
          
          If (StringField(RcvMsg,1,":") = "LogIn")
          TempMySqlConn.i = OpenDatabase(#PB_Any, "host=MyServer.com port=3306 dbname=Mydb", "userdb", "XXdjdya")
           
            If TempMySqlConn <> 0
    PrintN("[MySQL] Database connected !")
    
    If (DatabaseQuery(.........)  
    ..........
    endif  

  Else
    ConsoleColor(12,0)
    PrintN("[MySQL] Erro in connect on Database.")
    End
  EndIf 
          EndIf
  Until XX = XX 

or can i set ' All MySql Connection ' id to ' 0 ' like this :

Code: Select all

OpenDatabase(0, "host=MyServer.com port=3306 dbname=Mydb", "userdb", "XXdjdya")

??

[spikey]

Server receive both messages, the first connected and sent to message runs the functions first, and the second waits in the queue until the server runs?

Yes up to a point, the socket buffer space isn't unlimited. It is possible to overflow the receive buffer if there is a lot of unprocessed incoming data. If this happens further received data will be dropped by the TCP/IP stack because it has nowhere to put it.

The example you show is serial. The database connection and query are both triggered by the network event and the network response loop pauses until the query is complete. This set up could be more vulnerable to overflow problems than threaded processing, depending on work load. (Threaded processing is more difficult to design, program and, especially, debug though).

or can i set ' All MySql Connection ' id to ' 0 ' like this :

Code: Select all

OpenDatabase(0, "host=MyServer.com port=3306 dbname=Mydb", "userdb", "XXdjdya")

??

Opening successive connections on a single ID will probably be a bad idea unless you have a matching CloseDatabase; I would expect it to lead to a memory leak in your program.

so if I want to initialize a mysql connection for each data request, I should do this:

1) Each concurrent database connection open will occupy some RAM on the server. Server memory management is quite complex so it's difficult to say exactly how much; but generally more connections = more RAM. Too many connections open will deprive the system of RAM and cause trouble elsewhere. How many connections is too many will depend on how much RAM your server has, what other duties it performs and what the underlying operating system is.

2) You may need to implement some kind of marshalling, although exactly what you need depends on the circumstances your process will encounter.
It could range from low concurrency (a low number of simultaneous users), low demand (not making many database queries), low query execution time (queries end quickly) through to high concurrency (many simultaneous users), high demand (making queries all the time), high execution time (queries are slower to finish).

At the low end of the scale you might be able to satisfy demand with a single thread and connection, however once the connection becomes saturated users will end up having to wait for the system to catch up and/or will experience problems. If this is the case then you will need multiple threads and connections to keep up with demand and will need some kind of marshalling.

'Env' wrote a module for load balanced worker threads. I haven't tried it out but it looks promising, you might gain something from it if you decide on multi-threading. My only reservation being that he uses KillThread to shut down threads. As you are working with databases you would need to make alternate arrangements to allow your threads to self-terminate properly to make sure that transactions get committed properly and connections are closed properly. See viewtopic.php?f=12&t=72247