运行我的php脚本时为什么一直出现内存分配错误？

Question

I'm iterating through a handful of csv files (none that exceed more than 320MB) to clean up and format the files how I need them using the follow script:

while($row = mysqli_fetch_array($rsSelect)){        

    $fileName = $row["file_name"];

    if(strpos($fileName,'DATA') == true){

        $file = $dir.$row["manifest_files"]."";
        echobr($file);
        $file1 = file_get_contents($file, null);

        unset($file);
        $file2 = str_replace('","','    ', $file1);

        unset($file1);
        $file3 = str_replace('"','', $file2);

        file_put_contents($dir.$row["file_name"].".txt",$file3,FILE_USE_INCLUDE_PATH);
        unset($file2);
        unset($file3);

}

I receive the following error no matter how high I set my memory limits within php.ini or unsetting variabeles where I can to free up memory. I've tried setting the limit inside the script as well and still no go. My machine has no shortage of RAM, enough to easily store when manipulating the files as I need them.

ERROR: ( ! ) Fatal error: Out of memory (allocated 683147264) (tried to allocate 364322204 bytes)

Answer 1

Using file_get_contents() requires the entire file to be read into memory in one big chunk. You're probably better off using fopen() with a loop around fgets(). This will read just one line at a time:

$fp = fopen('file.csv', 'r');
while (($line = fgets($fp)) !== false) {
    // $line is the whole line
}

Alternatively, you might be able to use fgetcsv() and process individual fields as needed:

$fp = fopen('file.csv', 'r');
while (($row = fgetcsv($fp)) !== false) {
    // $row is an array of values from the line
}