I'm working in PHP and creating a system with a lot of PHP-driven elements and I have noticed that some of my pages stop displaying text produced using the echo command.
I have made a small example of this. Of course, my program is not supposed to just print allt numbers from 1 to 10000, but this example demonstrates how the script just terminates without any warnings.
Example code:
<?php
for ($i = 1; $i <= 10000; $i++) {
echo $i, '<br>';
}
?>
Output:
1
2
More numbers...
8975
8976
8977
8
What is causing this? Is it a buffer issue, and how do I resolve it?
The fact that your code ran to completion on the cli suggests to me that your script is exceeding the ini.max_execution_time runtime configuration.
Note in the linked documentation that the value of this configuration on the cli is 0 which means it does not time out when run in that environment.
The default setting in the browser is 30 seconds.
You can show your current setting in the browser with:
echo ini_get('max_execution_time');
And you should be able to increase it with:
ini_set('max_execution_time', 0); // turns off timeout
If the script you have shown us behaves as you describe the there's something very wrong going on. If this is a Unix or Linux based system and its repeatedly exhibiting this behaviour then the kernel is terminating the script - unless it has been configured not to do so, the kernel will be forcing a core dump of the process.
Either go build a new system to run your code on or Google how to capture and diagnose a core dump on your operating system.
update
If xdebug is reporting the process is still running then it probably hasn't dumped its core, but "not producing output" != "not running". What state is the process in? What happens when you redirect the ouput? What is the end-to-end output channel when it misbehaves?
The problem did not lie directly with my PHP installation or the application itself, but somewhere in my IDE PHPStorm. When running the code with the same PHP interpreter outside of the IDE's wrappers, it all works fine. The procedures described by the many users here helped with that. Thank you.
Related
I wrote a small script to generate email addresses based on a pattern:
<?php
$host = '#gmail.com';
$prefix = 'email';
$total = 200000;
for($i = 0; $i <$total; $i++)
{
echo $prefix . $i . $host . PHP_EOL;
}
Now, if I run this script as $php generate.php it takes around 15 seconds to complete the output echo. However, redirecting output ($php generate.php > file) completes within a second.
Is this something to do with PHP's buffering mechanism's or part of some Linux behavior?
Printing to the console is always much slower on any operating system than writing to a file directly, because there are a lot more drivers and operating system operations the output data must go through.
File operations are heavily optimized (caching!), so it's always much faster than writing to any visual output device.
This is Linux that is causing the slowdown. The same would happen if you printed the output in a windows console. Each flush of the output is obliging the program to halt, the operating system to update its window, and the program to be given control to continue again. If these flushes are numerous and often, it may indeed slow down things quite a bit.
Writing to a file still requires the operating system to step in, but there is no overhead beyond what you'd normally see with a program that reads and writes files. That said, writing to the console is a handy tool for debugging a program and you should use it. Just be sure that when it runs on the production machine, it writes to a file log instead.
I've recently started using APC cache on our servers. One of the most important parts of our product is a CLI (Cron/scheduled) process, whose performance is critical. Typically the batchjob consists of running some 16-32 processes in parallel for about an hour (they "restart" every few minutes).
By default, using APC cache in CLI is a waste of time due to the opcode cache not being retained between individual calls. But APC also contains apc_bin_dumpfile() and apc_load_dumpfile() functions.
I was thinking these two function might be used to make APC efficient in CLI mode by having it all compiled sometime outside the batchjob, stored in a single dumpfile and having the individual processes load the dumpfile.
Does anybody have any experience with such a scenario or can you give good reasons why it will or will not work? If any significant gains could reasonably be had, either in memory use or performance? What pitfalls are lurking in the shadows?
Disclaimer: As awesome as APC is when it works in CLI, and it is awesome, it can equally be as frustrating. Use with a healthy load of patience, be thorough, step away from the problem if you're spinning, keep in mind you are working with cache that is why it seems like its doing nothing, it is actually doing nothing. Delete dump file, start with just the basics, if that doesn't work forget it try a new machine, new OS, if it is working make a copy, piece by piece expand functionality - there are loads of things that won't work, if it is working commit or make a copy, add another piece and test again, for sanity-check recheck the copies that were working before, cliches or not; if at first you don't succeed try try again, you can't keep doing the same thing expecting new results.
Ready? This is what you've been waiting for:
Enable apc for cli
apc.enable-cli=1
it is not ideal to create, populate and destroy the APC cache on every CLI request
- previous answer by unknown poster since removed.
You're absolutely right that sucks, lets fix it shall we?
If you try and use APC under CLI and it is not enabled you will get warnings.
something like:
PHP Warning: apc_bin_loadfile(): APC is not enabled,
apc_bin_loadfile not available.
PHP Warning: apc_bin_dumpfile(): APC is not enabled,
apc_bin_dumpfile not available.
Warning: I suggest you don't enable cli in php.ini, it is not worth the frustration, you are going to forget you did it and have numerous other headaches with other scripts, trust me its not worth it, use a launcher script instead. (see below)
apc_loadfile and apc_dumpfile in cli
As per the comment by mightye php we need to disable apc.stat or you will get a warnings
something like:
PHP Warning: apc_bin_dumpfile(): Excluding some files from apc_bin_dump[file].
Cached files must be included using full path with apc.stat=0.
launcher script - php-apc.sh
We will use this script to launch our apc enabled scripts (ex. ./php-apc.sh apc-cli.php) instead of changing the properties in php.ini directly.
#/bin/sh
php -d apc.enable_cli=1 -d apc.stat=0 $1
Ready for the basic functionality? Sure you are =)
basic APC persisted - apc-cli.php
<?php
/** check if dump file exists, you don't want to use file_exists */
if (false !== $dump_file = stream_resolve_include_path('apc.dump'))
/** so where were we lets have a look see shall we */
if (false !== apc_bin_loadfile($dump_file))
/** fetch what was stored last run just for fun */
if (false !== $value = apc_fetch('my.awesome.apc.store'))
echo "$value from apc\n";
/** store what gets fetched the next run just for fun */
apc_store('my.awesome.apc.store', 'awesome in cli');
/** what a shlep lets not do that all over again shall we */
apc_bin_dumpfile(array(),null,'apc.dump');
Notice: Why not use file_exists? Because file_exists == stat you see and we want to reap the reward that is apc.stat=0 so; work within the include path; use absolute and not relative paths - as returned by stream_resolve_include_path(); avoid include_once, require_once use the non *_once counterparts; check your stat usage, when not using APC(Muchos important senor), with the help of a StreamWrapper echo for calls to method url_stat; Oops: Fatal scope over-run error! aborting notice thread. see url_stat
message: Error caused by StreamWrapper outside the scope of this discussion.
The smoke test
Using the launcher execute the basic script
./php-apc.sh apc-cli.php
A whole bunch of nothing happened that's what we want right, why else do you want to use cache? If it did output anything then it didn't work, sorry.
There should be a dump file called apc.dump see if you can find it? If you can't find it then it didn't work, sorry.
Good we have the dump file there were no errors lets run it again.
./php-apc.sh apc-cli.php
What you want to see:
awesome in cli from apc
Success! =)
There are few in PHP as satisfying as a working APC implementation.
nJoy!
I would definitely not use it in the CLI as when you restart it, it's almost as if it was never running in the first place!
The better way of using APC is to have it running on the webserver itself all the time, this way with it being active it will actually do what it's supposed to do!
I tryed with curl and APC.it works
use these commands in CLI
curl --data "param1=value2" http://testsite.com/test.php
so it will post data to test.php and you writes the code in it.
I have an object for tasks and on __deconstruct(), it's meant to run some of the lengthier cleanup tasks after the rest of the page has already loaded. Unfortunately, it buffers the output and won't send it until after the tasks are finished (nothing is printed in the tasks).
I've read through http://www.php.net/flush and tried all the suggestions there. Obviously I've tried disabling output_buffering in php.ini. I've disabled deflate_module, zlib compression is off, don't have mod_gzip. Calling flush() or ob_flush() has no effect, nor does enabling implicit_flush.
I'm just running XAMPP (currently apache 2.2.17, php 5.3.4) under Windows Server 2008 R2. PHP is being run as a module.
And yes, I could set up some little AJAX hack to run the task manager or even set up a scheduled task to run this specific task, but output buffering has been an issue elsewhere, too. Would just like it to be gone sometimes.
From a similar thread, someone suggested seeing what the following would do:
<?php
while (TRUE)
{
echo 'x';
flush();
sleep(1);
}
?>
As expected, the page displays nothing until the maximum execution time is reached, at which point it flushes the buffer.
This has become extremely frustrating. Anyone have any ideas what could still be causing it to buffer?
You're only sending a small amount of data. Browsers have their own buffer, which can be based on a number of bytes, by which elements have been received, or by something else.
In short, there is nothing you can do about this. The buffering is happening client-side, not server-side. You could try sending more data before your xs.
You can prove this by packet sniffing the connection between the server and the browser, with Wireshark or similar.
hmmm, interesting grabbed a snip of code I have used else where and it works as expected...
https://stackoverflow.com/a/9728519/632951
<?php
echo str_repeat('fillerbytes',20*1024/strlen('fillerbytes'));
echo '<body style="font-size:6px;font-family:arial;">';
echo str_repeat('<br>',2);
for($i=1; $i<=5000; $i++){
echo $i . ' ';
ob_flush();
flush();
usleep(2000); // 2 ms each = 10s total
}
?>
Watch my server count to 5000 http://atwebresults.com/texttest/new.php
(Doesn't work on some free hosts like freehostingeu.com.)
Is there a way to view the PHP error logs or Apache error logs in a web browser?
I find it inconvenient to ssh into multiple servers and run a "tail" command to follow the error logs. Is there some tool (preferably open source) that shows me the error logs online (streaming or non-streaming?
Thanks
A simple php code to read log and print:
<?php
exec('tail /var/log/apache2/error.log', $error_logs);
foreach($error_logs as $error_log) {
echo "<br />".$error_log;
}
?>
You can embed error_log php variable in html as per your requirement. The best part is tail command will load the latest errors which wont make too load on your server.
You can change tail to give output as you want
Ex. tail myfile.txt -n 100 // it will give last 100 lines
See What commercial and open source competitors are there to Splunk? and I would recommend https://github.com/tobi/clarity
Simple and easy tool.
Since everyone is suggesting clarity, I would also like to mention tailon. I wrote tailon as a more modern and secure alternative to clarity. It's still in its early stages of development, but the functionality you need is there. You may also use wtee, if you're only interested in following a single log file.
You good make a script that reads the error logs from apache2..
$apache_errorlog = file_get_contents('/var/log/apache2/error.log');
if its not working.. trying to get it with the php functions exec or shell_exec and the command 'cat /var/log/apache2/error.log'
EDIT: If you have multi servers(i quess with webservers on it) you can create a file on the machine, when you make a request to that script(hashed connection) you get the logs from that server
I recommend LogHappens: https://loghappens.com, it allows you to view the error log in web, and this is what it looks like:
LogHappens supports kinds of web server log format, it comes with parses for Apache and CakePHP, and you can write your own.
You can find it here: https://github.com/qijianjun/logHappens
It's open source and free, I forked it and do some work to make it work better in dev env or in public env. That is:
Support token for security, one can't access the site without the token in config.php
Support IP whitelists for security and privacy
Sopport config the interval between ajax requests
Support load static files from local (for local dev env)
I've found this solution https://code.google.com/p/php-tail/
It's working perfectly. I only needed to change the filesize, because I was getting an error first.
56 if($maxLength > $this->maxSizeToLoad) {
57 $maxLength = $this->maxSizeToLoad;
58 // return json_encode(array("size" => $fsize, "data" => array("ERROR: PHPTail attempted to load more (".round(($maxLength / 1048576), 2)."MB) then the maximum size (".round(($this->maxSizeToLoad / 1048576), 2) ."MB) of bytes into memory. You should lower the defaultUpdateTime to prevent this from happening. ")));
59 }
And I've added default size, but it's not needed
125 lastSize = <?php echo filesize($this->log) || 1000; ?>;
I know this question is a bit old, but (along with the lack of good choices) it gave me the idea to create this tiny (open source) web app. https://github.com/ToX82/logHappens. It can be used online, but I'd use an .htpasswd as a basic login system. I hope it helps.
I've installed AjaXplorer (very nice web file explorer), written in PHP, on my IIS (Windows Server 2008 SP2 x64). It works too slow for me.
What can be the cause? Are there some settings in php.ini? Or, maybe, something is wrong with IIS?
I use 32-bit PHP, php-cgi.exe as interpreter.
Regards,
First off, CGI will always be slow. It needs to boot the entire PHP runtime for each request. Try using FastCGI (If you're using IIS 7, or if you're using IIS 6)...
After that, try to see why it's slow. Is it because the PHP script takes a long time to execute (meaning it's a code issue), or is it because of a server config. To test, modify this into the start of the entrance point of the PHP program (index.php):
define(START_TIME_CUSTOM, microtime(true));
function onEndTimeCompute() {
$timeTaken = microtime(true) - START_TIME_CUSTOM;
echo "Completed In: ".number_format($timeTaken, 4)." Seconds\n";
}
register_shutdown_function('onEndTimeCompute');
That write Completed in n Seconds to the end of the generated output (even if die() is called). It may cause some issues if Ajax calls are expected to return JSON, so don't do it as a rule, just for trying to figure out what's going on.
So, if the total request takes 1 second, yet you see Completed in 0.004 Seconds, you know that the PHP code itself is not the issue (it's either in the setup of the interpreter by CGI, or somewhere else in IIS)...
That should at least show you where the problem is...