multithreading in ph`p?

[Santonian]

Hello,

I am wondering if it's possible to do multi threading in php?
I have to do some http queries and want to run them simutaniously.

Anyone know anything about that?

thanx
S.

[ir4z0r]

afaik that's not possible, sry.

[HalfaBee]

If you are on a unix host you could probably use the exec() function to run multiple scripts to do the calls.
Obviously it would not be completely synchronous.
What are you trying to acheive?

HalfaBee

[cosminb]

It's possible.
See: http://www.php.net/manual/en/function.pcntl-fork.php

[Santonian]

Ah cool. That should do the job.

Does it work only on unix based machines or on windows also? I am running the script on a unix based machine but developing on windows. (I am not home atm, so I can't test)

To the previously question:
I have a script on a webhost somewhere and sending an xml file to it. Then the script on the host sends me the answer, an xml file as well. So far so good. But I have to do up to 20-30 of this things after an other and one takes around 1-1.2 seconds.
The idea is to run them simustaniously to save time.

S.

[Santonian]

ok, I found the answer already:

Note: Currently, this module will not function on non-Unix platforms (Windows).

[cosminb]

Be carreful because it may cause your web server to crash....

[Santonian]

Hmm.. can you explain why that can happen? And what I have to take care of taht it doesn't happen?

[cosminb]

From the PHP Manual:
Process Control support in PHP implements the Unix style of process creation, program execution, signal handling and process termination. Process Control should not be enabled within a webserver environment and unexpected results may happen if any Process Control functions are used within a webserver environment.

[Santonian]

I read that...

Do you have more information about that?
Do you have first hand experience?
Does this always happen?

thanx
S.

[rowan]

unless you're using a multiple processors or machines, running your request concurrently will be slower. perhaps your delay comes from sending each request individually? maybe there is a way you can send and receive them as a batch.

[Santonian]

As far as I could figure it out the delay comes from the answer wait time. I send my request and then it takes 0.8 seonds until the answer is retrieved... So I hope that when I send all the requests, more or less, at the same time it reduce the total wait time... 😕

I have no idea if it works, but I'll try...

what do you mean with batch job?

[rowan]

if the complexity of the query is what causes the delay, then only way to reduce that time it to improve the efficiency of the query function (or buy more expensive hardware. 😉 )

however, it is more likely the delay is sending each request across the network and waiting for the response to make its way back. if you can send all of your queries in one go (one batch), maybe in an array then the overhead of sending each individual query is reduced.

this, of course, depends on if you have access to change the remote script...

[Santonian]

hmm... I dont have access on the remote script.

So I have to send one query after an other... 🙁