CODEWITHSUNDEEP
phpfgets
mike
mike

Reputation:

What is it about PHP's fgets() that makes it so horrible on large files?

What is it about fgets() implementation that makes it so horrible on large files vs fread?

To demonstrate, run this code:

<?php
$line = str_repeat('HelloWorld', 100000) . "\n";
for($i=0; $i<10000; ++$i)
    file_put_contents('myfile', $line, FILE_APPEND);
//now we have roughly a 1gig file

// We'll even let fread go first incase
// the subsequent test would have any caching benefits
$fp = fopen('myfile2','r');
$start = microtime(true);
while (fread($fp,4096));
$end = microtime(true);
print ($end-$start) . " using fread\n";
fseek($fp, 0);

$start = microtime(true);
while (fgets($fp));
$end = microtime(true);
print ($end-$start) . " using fgets\n";
?>

Upvotes: 2

Views: 3074

Answers (1)

nickf
nickf

Reputation: 546035

It might have something to do with how you're calling fgets. From the manual, it says that if you leave the second parameter out, then:

If no length is specified, it will keep reading from the stream until it reaches the end of the line.

If the data your working with has some very long lines (eg: "HelloWorld" 100,000 times = 1,000,000 characters), then it has to read that whole thing.

Again, from the manual:

If the majority of the lines in the file are all larger than 8KB, it is more resource efficient for your script to specify the maximum line length.

Upvotes: 5

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