NYCPHP Meetup

[Anthony Papillion]

Michele,

Thank you for your input. I'm glad I seem to be on the right track here and 
I'm curious about what others might think of this method of walking the 
database too.

I hadn't thought about the additional logic part in the event of an error. 
How would you propose that be handled? Perhaps a 'current time' field that's 
updated after each operation?  We could assume that a 'current time' that's 
more than, say 15 minutes, is an indication of the row needing to be 
processed even though the status might be 'processing'. What do you think 
about that?

Thanks,
Anthony

----- Original Message ----- 
From: Michele Waldman
To: 'NYPHP Talk'
Sent: Sunday, February 14, 2010 7:55 PM
Subject: Re: [nycphp-talk] Best way to accomplish this task


As I was reading, I was thinking that would be my approach.

I'm not seeing anything ugly about it.  Records being processed should have 
a status as such.

You might have some additional logic, that picks up records in the event one 
of the processes fail for some reason.   Sever goes down or some one 
accidently kills the process, etc.

We'll see what the other folks think.

Michele



From: talk-bounces at lists.nyphp.org [mailto:talk-bounces at lists.nyphp.org] On 
Behalf Of Anthony Papillion
Sent: Sunday, February 14, 2010 8:50 PM
To: 'NYPHP Talk'
Subject: [nycphp-talk] Best way to accomplish this task


Hello Everyone,

I'm designing a system that will work on a schedule. Users will submit data 
for processing into the database and then, every minute, a PHP script will 
pass through the db looking for unprocessed rows (marked pending) and 
process them.

The problem is, I may eventually have a few million records to process at a 
time. Each record could take anywhere from a few seconds to a few minutes to 
perform the required operations on. My concern is making sure that the 
script, on the next scheduled pass, doesn't grab the records currently being 
processed and start processing them again.

Right now, I'm thinking of accomplishing this by updating a 'status' field 
in the database. So unprocessed records would have a status of 'pending', 
records being processed would have a status of 'processing' and completly 
processed record will have a status of 'complete'.

For some reason, I see this as ugly but that's the only way I can think of 
making sure that records aren't duplicatly processed. So when I select 
records to process, I'm ONLY selecting one's with the status of 'pending' 
which means they are new, unprocessed.

Is there a better, more eleqent way of doing this or is this pretty much it?

Thanks!
Anthony Papillion



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