Re: Re: how dod you get to do multiple mysql queries concurrently?

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On Fri, January 25, 2008 1:45 pm, Jochem Maas wrote:
> Richard Lynch schreef:
>> On Fri, January 25, 2008 11:33 am, Floor Terra wrote:
>>>>>>> I know how to do multiple queries - the key issue in my
>>>>>>> question
>>>>>>> was how to do them concurrently (i.e. in parallel).
>>>>>> So you want to make PHP multithreaded???
>>>>> No, just the mysql queries.
>>> Try pcntl_fork() to create a child process for each query.
>>> Each child can make it's own MySQL connection.
>>
>> Do *NOT* do this in a web-server environment, unless you have
>> EXTENSIVELY and EXHAUSTIVELY tested all your PHP extensions for
>> thread-safety!
>
> I agree about the don't do that part - but what has process forking
> got to do with thread safety?
>
> AFAIK you shouldn't do that because it madness to fork a complete
> apache
> process.

Process forking has EVERYTHING to do with thread safety.

Whatever is going to go wrong in a threaded environment is going to
also go wrong when you fork the process, almost for sure.

"Global" variables (or other resources) will not get split/duplicated
correctly, as fork has NO IDEA what needs separating.

So you suddenly have two processing pounding data in/out of what each
of them think is an exclusive resource/memory-address/whatever...

Baby go Boom!

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