Posted by tony on 06/11/06 10:41

In article <xPxig.3721$sC.2396@fe24.usenetserver.com>,
david.haynes2@sympatico.ca says...
>
> A slow down of this magnitude typically points to some system-related
> bottleneck rather than an algorithmic one. Have you checked the
> processes' virtual memory use? I would suspect that you are starting to
> swap around the 6,000th record.
>
> If not, I would start to place finer-grained time information around the
> major I/O points (fgetcsv, fwrite) to see if they are causing the slow down.
>
> On a stylistic note, why do you use $x++ in some places and $x += 1 in
> others? Also, the checkit function could use the trinary compare operator:
>
> function checkit($star) {
> exec('declination.exe '.$star, $aout, $returnval);
> return ($aout[0][0] === 'Y');
> }
>
> and 'if( $checkit($star) == false ) {' could become
> 'if( ! $checkit($star) ) {'
>
> However, I don't think any of these would contribute to your slow down
> issue.
>
> -david-
>

Thanks for the comments david - I've run this on both windows and linux
now and the linux system I ran through apache - I get the same results on
that too (very similar but not identical) (The linux box is entirely
different hardware) - I'll post timing differences later - they're
outrageous !!!

I've also run the windows version with apache too now and still get the
slowdown.

I've tried removing my call to the executable replacing it with a simple
return and it still slows down.

Looking at what you suggest - could it be that the fgetcsv command is
searching from the top of the file on every itteration?
I dont cause it to - but if thats how it works ?

I have discovered a windows loss of 2Mb of system memory for every run -
thats either a windows or PHP problem I dont know which - probably
windows and I dont think its connected to the slowdown.

If this isnt obvious to anyone I guess the only thingI can do is start
taking things out one by one starting with your suggestions.

On the memory side - no it all(suprisingly) seems to happen in ram - even
the test database file of 1 million records seems to go straight to ram.
There's no thrashing or anything (The win-98 system has 1Gb ram - the
linux system just 128Mb)

On the style front - Dave you wouldn't believe my working methods!
In my time I've used maybe 7 languages in anger and currently I use 3 or
4 so I'm in and out of them all the time - things get mixed up in my
head.
I always do a "comment" sweep when I'm done and tidy things up for this
very reason but sometimes I do use ++x and += 1 because it helps me
remember whats going on and what I need to keep an eye on. (I have a bad
short term memory problem) My "if" statements and other stuff follow the
same routine for the same reasons - there is method in my madness - you
just have to be mad too to see it...
This particular code has been messed about with quite badly too as I try
to find the problem.

I care more about function not fancy - most PHP style I've seen is
abysmal anyway - the standard style reccomended is appaling. I'm not a
fan of the way most people code - nor of the way many languages work for
that matter. Anything other than Forth is bad form in my book ;-)

As for the trinary operator - its a terrible construct for anyone who
doesn't use it regularly or anyone looking at someone elses code so I
avoid it.

tony

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