Re: Limit to the number of sockets socket_select can supervise?

From:	Jed Smith	Date:	Sat, 20 Nov 2004 23:47:39 +0000
Subject:	Re: Limit to the number of sockets socket_select can supervise?
References:	1	Groups:	php.general
Request:	Send a blank email to php-general+get-202579@lists.php.net to get a copy of this message

Let me attack this. I'm bored. I'm on Windows XP SP 2, and I'll try this from the command line. I coded a simple server in PHP that just accepts the connection and listens. It doesn't attempt to send any data, its only select loop is to wait for a new connection attempt. I also wrote a load program. When attempted with 49 sockets (50 on the server), it worked fine, select and all. Server: http://labs.jed.bz/HCJ/server.php.txt Client: http://labs.jed.bz/HCJ/load.php.txt However, when I tried 500, odd things happened. The server (!) died due to Windows XP's DEP, which I removed for cli.exe and retried. It then died again (!) because of "an existing connection [being] forcibly closed". I then lowered the limit to 70 and tried again. The server accepted 69:

accepted #68 of 70                          accepted #69 of 70 .......................

Before I could telnet in to make 70, the client died:

connecting #69 of 69 ... ok                                                     waiting for spew                                                                                                                                                Warning: socket_select(): unable to select [0]: An operation was attempted on something that is not a socket.                                                    in F:\Projects\HCJ\load.php on line 38                                         spew!                                                                           done!

Curious. The problem replicates itself here. I'm not sure. For the first time with PHP I honestly have no clue where to start attacking this problem. It could be a Windows limitation, but for that to be the case the scripts will have to be run on a UNIX system as well. I simply don't know. Very strange indeed. It was worth the hour I put into it, because I'm interested -- I've been playing with PHP daemons on Win32 for a while now, and this select limitation concerns me. I'll submit this as a bug report. Feel free to comment, bug #30852 Jed Hans-Christian Jehg wrote:

Hi Im building a TCP server in PHP 5.0.2 on Windows. It will have to serve a lot of clients (500+) with low traffic. During this I have noticed that socket_select seems unable to supervise more than 64 connections at a time (Not good when I need 500+). It stops with a message that "Socket select failed, error code is: 10038, error message is: An operation was at tempted on something that is not a socket." These are the outputs of socket_last_error() and socket_strerror(socket_last_error()). And now forthe questions: Does any of you have the same experience? Is it something to do with Windows? Does this limitation exist on Linux? Is it just a bug? Any good suggestions? Best regards and thanx in advance HC