Error 500 when bringing many records

Question

Error 500 when bringing many records

Asked 6 years, 2 months ago

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-1

I’m trying to display data in a table through a foreach in the php of more than 17,000 database records, but shows HTTP ERROR 500 in the browser.

 <?php foreach($dados as $dado):?>
   <tr>
      ... // aqui vai os registros
   </tr>
 <?php endforeach;?>

The interesting thing is that when I limit the amount of records to display, for example 5 thousand, the error does not occur.

Would that be a memory problem of php?

Maybe I shouldn’t use the foreach?

Edit:

Apache log:

[Fri Sep 21 10:06:00 2018] [error] [client 192.168.0.100] PHP Fatal error:  
Allowed memory size of 134217728 bytes exhausted (tried to allocate 27316224 
bytes) in Unknown on line 0, referer: 
http://192.168.0.100/index.php/relatorio/

1

You need to look at the apache error log.

– rray

2018/09/21 at 12:19
thanks for the tip.. really set the memory limit. I should increase or treat this in php?

– SM_S

2018/09/21 at 12:28
1

As for the negative seems a bit exaggerated, use the [Edit] link and add the log error message. The way it is, you can’t tell where the problem is.

– rray

2018/09/21 at 12:28
1

The ideal would be not to bring all the records.

– rray

2018/09/21 at 12:29
I edited with the log. Maybe breaking in parts sql and bringing gradually

– SM_S

2018/09/21 at 12:33
2

The solution will be to paginate the data even, there is not much to do. The question is: do you really need 17 thousand records on the same page? This seems to be unnecessary. Up to 5 thousand seems to be too.

– Woss

2018/09/21 at 12:40
Yes, it’s a report and if I use paging, the excel plugin doesn’t work. Is there any way to clear the memory in each loop iteration?

– SM_S

2018/09/21 at 12:41
1

A: You don’t need to create one array with all bank records. apparently you have in $dados all records, but usually the database driver implements a pointer scheme between records, making it possible to have only one record in memory at a time. Two: if PHP is generating an HTML code from the records, with 17,000 records the HTML will be gigantic, but you can facilitate the life of your server by releasing the output buffer with each iteration.

– Woss

2018/09/21 at 14:12

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by Lima Chaves • **161** points · Answer 1 · 2018-09-21T13:54:41+00:00

The error is happening because your script is consuming more resources than php is set to allow. You could raise the limit, but I wouldn’t recommend it because it’s the equivalent of throwing the dust under the mat.

The ideal would be for you to inspect your code to find out where the memory leak is. I already went through a similar problem and refactoring the code I was able to reduce the memory usage from 3GB to 300MB. One of the changes I made was to exchange the foreach for a for as follows:

for ($i=0, $n = count($dados); $i < $n; $i++){
    $dado = $dados[$i]; //Instancia uma variável para trabalhar nesse escopo

    ... //Sua lógica aqui, usando $dado;

    unset($dados[$i]); //Libera memória a cada interação

}

You can measure memory consumption by adding memory_get_usage() at the beginning or end of each loop interaction.

echo ((memory_get_usage(true)/1024)/1024) . 'MB';

NOTE: I read today that the use of a loop foreach ($foo as &$bar) is lighter when using heavy data arrays. But use with caution as this same syntax tends to be slower when using little data.