PHP flush problem

Question

Ok, so I have this PHP script that runs in a nice little infinite loop (with sleeps, don't worry). I use it as a page I can go to from any computer to monitor my database statistics. Every 2 seconds, it gets stats from the DB and displays them on the screen.

Now, this works just fine on XAMPP on my Windows machine. I'm trying to get it to work on my linux webserver, running apache2 with PHP 5.3.5, but for some reason it won't actually display anything (it doesn't go to a blank page, it just stays at the page I was at before going to the monitor page, but with the "working" wheel spinning). I feel like this is some sort of caching thing, it doesn't want to display the page until it's finished running the script (although I NEED it to). I use flush() and ob_flush() after every 2 seconds, and I made sure that output_buffering = off and zlib.output_compression = off in my php.ini file.

I realize this question seems to have been asked a lot, but I've tried everything I can find on the subject with ultimate failure.

NOTE: like I said, this works FINE on my XAMPP install with apache and PHP 5.3.6. My question isn't so much about how to find alternatives, but more with regards to WHY it works there but not on my linux webserver.

This doesn't answer your question, but why do you prefer this over redirecting to itself with JS after 2 seconds instead of sleeping? The flushing problem would not have appeared with that approach. — Jon
– Jon, Commented May 8, 2011 at 18:49
I would suggest looking at other ways to return the data. As suggested a meta/Javascript refresh or perhaps do this via a console script and a SSH session. What db data are you returning? — James C
– James C, Commented May 8, 2011 at 19:34

eykanal · Accepted Answer · 2011-05-08 18:52:13Z

2

Having php script run for an "infinite" amount of time is almost never appropriate. You can:

set the page to reload using html (<meta http-equiv="refresh" content="5">)
set it to run and display via a cron script
reload the page regularly using javascript
something else I haven't thought of

All of these ways of approaching the problem would save you the type of headaches you're experiencing now.

answered May 8, 2011 at 18:52

eykanal

27.2k19 gold badges86 silver badges114 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

Jordan Over a year ago

Yes, I have considered all of the above. The problem is that the script keeps track of results from each of 2 second updates and shows an average over time. I could make it so it sticks the results every 2 seconds in a DB and then queries them on load to get an average, but this just adds excessive inserts and queries, and I have to create a new connection to the DB every 2 seconds when the page reloads.

eykanal Over a year ago

There's no way you can have the data being monitored sent to a log file to be analyzed after the fact? It has to be done with an infinitely running php file? I would be very surprised if that was the case.

Jordan Over a year ago

I'd rather avoid the log file, since seeing a current rate (i.e. real time data) is quite important for this application.

eykanal Over a year ago

Log file + php backend + ajax reloading of front-end = as close to real-time as you can get. Having the file run infinitely is actually worse that that, since php running continuously != client display showing real-time data.

Ibu · Accepted Answer · 2011-05-08 19:12:38Z

1

Here is what you can do,

Have your script write the parameters to the javascript, so you can reload your page every 2 seconds with new parameters. example:

<script type='text/javascript'>

setTimeout(function() {
   location.href="http://www.example.com/?jobid=<?php echo $nextJobId ?>";
},2000);
</script>

so if you need to do a Db offset on each sql query, you can pass that parameter in the url. Having an infinite loop might seem like a good idea, but maybe you should reevalute your code and see if you really need it, or if you can implement it this way

answered May 8, 2011 at 19:12

Ibu

44k14 gold badges82 silver badges109 bronze badges

Collectives™ on Stack Overflow

PHP flush problem

2 Answers 2

4 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

4 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related