1.2.1638. fputcsv() In Loops

fputcsv() is slow when called on each row. It actually flushes the data to the disk each time, and that results in a inefficient dump to the disk, each call.

To speed up this process, it is recommended to dump the CSV to memory first, then dump the memory to the disk, in larger chunks. Since fputcsv() works only on stream, it is necessary to use a memory stream.

The speed improvement is significant on small rows, while it may be less significant on larger rows : with more data in the rows, the file buffer may fill up more efficiently. On small rows, the speed gain is up to 7 times.

<?php

// Speedy yet memory intensive version
$f = fopen('php://memory', 'w+');
foreach($data_source as $row) {
    // You may configure fputcsv as usual
    fputcsv($f, $row);
}
rewind($f); // Important
$fp = fopen('final.csv', 'w+');
fputs($fp, stream_get_contents($f));
fclose($fp);
fclose($f);

// Slower version
$fp = fopen('final.csv', 'w+');
foreach($data_source as $row) {
    // You may configure fputcsv as usual
    fputcsv($fp, $row);
}
fclose($fp);
?>

1.2.1638.1. Connex PHP features

• csv

1.2.1638.1.1. Suggestions

• Use fputcsv() on a memory stream, and flush it on the disk once

1.2.1638.1.2. Specs

Short name	Performances/CsvInLoops
Rulesets	All, Performances, Top10
Exakat since	1.5.5
PHP Version	All
Severity	Minor
Time To Fix	Quick (30 mins)
Precision	High
Available in	Entreprise Edition, Exakat Cloud