Mysqli Result Fetch_Row Memory Leak

Question

I use mysqli API to query a large table, every 1000 rows, but the memory of my server grows up very fast. The memory is 0, even the swap. I don't know how to fix it.

The table has 4 million rows so I query the table each time by 1000.

Here is my code:

<?php
    ini_set('memory_limit','32M');
    $config = require_once('config.php');
    $attachmentRoot = $config['attachment_root'];
    $mysqli = new mysqli($config['DB_HOST'],$config['DB_USER'],$config['DB_PASSWORD'],$config['DB_NAME']);
    $mysqli->set_charset('gbk');
    if(!$mysqli)
        throw new Exception('DB connnect faild:'.mysqli_connect_errno().mysqli_connect_error());
    echo "\nRename The Dup Files With Suffix: .es201704111728es \n";
    $startTime = microtime(true);
    /**
     *
     * Move dup file to $name + .es201704111728es
     */
    $suffix = ".es201704111728es";
    $fileLinesLimit = 100000;
    $listSuffix = 0;
    $lines = 0;
    /**
     * Create File List.
     */
    $fileList = '/tmp/Dupfilelist.txt';
    $baseListName = $fileList.$listSuffix;
    //$fs = fopen($baseListName,'w');
    $totalSize = 0;
    $start = 0;
    $step = 10000;
    $sql = "SELECT id,filepath,ids,duplicatefile,filesize FROM duplicate_attachment WHERE id> $start AND  duplicatefile IS NOT NULL LIMIT $step";
    $result = $mysqli->query($sql);
    while($result->num_rows > 0)
    {
        while($result->fetch_row())
        {
            /*$fiepath = $row[1];
            $uniqueIdsArray = array_unique(explode(',',$row[2]));if(empty($row[3]))throw new \Exception("\n".'ERROR:'.$row[0]."\n".var_export($row[3],true)."\n");
            $uniqueFilesArray = array_unique(explode(',',$row[3]));
            $hasFile = array_search($fiepath,$uniqueFilesArray);
            if($hasFile !== false)
                unset($uniqueFilesArray[$hasFile]);
            $num = count($uniqueIdsArray);
            $fileNum = count($uniqueFilesArray);
            $ids = implode(',',$uniqueIdsArray);
            if($num>1 &&  $fileNum>0){
                //echo "\nID: $row[0] . File Need To Rename:".var_export($uniqueFilesArray,true)."\n";

                $size = intval($row[4]);
                if($lines >= $fileLinesLimit){
                    $lines = 0;
                    $listSuffix++;
                    //$fileList .= $listSuffix;

                }

                array_map(function($file) use ($attachmentRoot,$suffix,$fiepath,$totalSize,$size,$fileLinesLimit,&$listSuffix,&$lines,$fileList){
                    //$fs = fopen($fileList.$listSuffix,'a');
                    if($file === $fiepath)
                        return -1;
                    $source = $file;
                    $target = $source.$suffix;
                    //rename($source,$target);
                    //fwrite($fs,$source.','.$target."\n");
                    //file_put_contents($fileList.$listSuffix, $source.','.$target."\n",FILE_APPEND);
                    //$totalSize += intval($size);
                    $lines ++;
                    //echo memory_get_usage()."\n";
                    //fclose($fs);
                    //unset($fs);



                    //try to write file without amount memory cost
                    //$ts = fopen('/tmp/tempfile-0412','w');



                },$uniqueFilesArray);
                //echo "Test Just One Attachment Record.\n";
                //echo "Ids:$ids\n";
                //exit();
            }*/
        }

    echo memory_get_peak_usage(true)."\n";

        if(!$mysqli->ping())
        {
            echo "Mysql Conncect Failed.Reconnecting.\n";
            $mysqli = new mysqli($config['DB_HOST'],$config['DB_USER'],$config['DB_PASSWORD'],$config['DB_NAME']);
            $mysqli->set_charset('gbk');
            if(!$mysqli)
                throw new Exception('DB connnect faild:'.mysqli_connect_errno().mysqli_connect_error());
        }
        //mysqli_free_result($result);
        $result->close();
        unset($result);
        $start += $step;
        $sql = "SELECT id,filepath,ids,duplicatefile,filesize FROM duplicate_attachment WHERE id> $start AND  duplicatefile IS NOT NULL LIMIT $step";
        $result = $mysqli->query($sql);
    }
    echo "Dup File Total Size: $totalSize\n";
    echo "Script cost time :".(microtime(true)-$startTime)." ms\n";sleep(1000*10);
    mysqli_close($mysqli);
    exit();

Answer 1

I enable the XDEBUG extension.Sorry for that.

I disable this extension and everything goes well.