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Posted by Jerry Stuckle on 01/26/08 01:33
Martin wrote:
> On Fri, 25 Jan 2008 11:27:00 -0800 (PST), ZeldorBlat
> <zeldorblat@gmail.com> wrote:
>
>> On Jan 25, 11:25 am, Martin <martinval...@comcast.net> wrote:
>>> I have a series of php scripts that provide the user interface to an
>>> industrial automation program.
>>>
>>> One of the scripts serves out a page which displays some data, some
>>> of which is constantly changing. On that page, I have some AJAX code
>>> running that frequently requests fresh data and displays it
>>> (frequently means about once a second).
>>>
>>> When the php script that services the AJAX requests receives one, it
>>> passes a request of its own over to the main process (via a socket)
>>> which responds with some data which the script then sends out to the
>>> browser page.
>>>
>>> This all works fine but I'm concerned about the load this exchange of
>>> data places in the main process.
>>>
>>> What I'm wondering is: would it be possible that I could have my main
>>> process send its data (in real time) to "something" in the php system
>>> such that the php script could access this data much like it accesses
>>> its own global variables? IOW, the script would have immediate access
>>> to the values instead of having to request them from the main process.
>>>
>>> Please understand that all of this activity is running on one computer
>>> and this is all confined to an inTRAnet (there's no internet access
>>> involved). And, this one computer is entirely under my control. I am
>>> free to do what ever needs to be done with regards to php
>>> configuration, security settings, etc.
>>>
>>> Any recommendations?
>>>
>>> Thanks.
>> Sounds likes a database would work just fine. The main process can
>> update values in the database and the PHP script can read them
>> whenever it needs to. Or perhaps I'm missing something larger here...
>
> Yes, I agree - a database probably would work ok. But, even then,
> there would be a lot of disc activity. I'm thinking that if the data
> could be stored in memory somewhere/someway, then the processing time
> would be minimized.
>
> I'm also thinking that if the processing time is minimized, then I
> could speed up the frequency of the AJAX requests (and thus provide a
> more real-time appearance to the viewer's screens).
>
>
>
Your limitation is probably going to be network, not disk activity.
Also, databases and your OS cache a lot of data. You can store it in
memory, but then you're going to go through a lot of trouble (and CPU
cycles) retrieving and sorting it.
Allow the database to do its job.
--
==================
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
jstucklex@attglobal.net
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