PHPExcel用完了256,512和1024MB的RAM

Question

我不明白.XSLX表大约3MB,甚至1024MB的RAM还不足以让PHPExcel将其加载到内存中？

我可能在这里做了一些可怕的错误:

function ReadXlsxTableIntoArray($theFilePath)
{
    require_once('PHPExcel/Classes/PHPExcel.php');
    $inputFileType = 'Excel2007';
    $objReader = PHPExcel_IOFactory::createReader($inputFileType);
    $objReader->setReadDataOnly(true);
    $objPHPExcel = $objReader->load($theFilePath);
    $rowIterator = $objPHPExcel->getActiveSheet()->getRowIterator();
    $arrayData = $arrayOriginalColumnNames = $arrayColumnNames = array();
    foreach($rowIterator as $row){
        $cellIterator = $row->getCellIterator();
        $cellIterator->setIterateOnlyExistingCells(false); // Loop all cells, even if it is not set
        if(1 == $row->getRowIndex ()) {
            foreach ($cellIterator as $cell) {
                $value = $cell->getCalculatedValue();
                $arrayOriginalColumnNames[] = $value;
                // let's remove the diacritique
                $value = iconv('UTF-8', 'ISO-8859-1//TRANSLIT', $value);
                // and white spaces
                $valueExploded = explode(' ', $value);
                $value = '';
                // capitalize the first letter of each word
                foreach ($valueExploded as $word) {
                    $value .= ucfirst($word);
                }
                $arrayColumnNames[] = $value;
            }
            continue;
        } else {
            $rowIndex = $row->getRowIndex();
            reset($arrayColumnNames);
            foreach ($cellIterator as $cell) {
                $arrayData[$rowIndex][current($arrayColumnNames)] = $cell->getCalculatedValue();
                next($arrayColumnNames);
            }
        }
    }
    return array($arrayOriginalColumnNames, $arrayColumnNames, $arrayData);
}

上面的函数将数据从excel表读取到数组.

有什么建议？

起初,我允许PHP使用256MB的RAM.这还不够.然后我把数量增加了一倍,然后尝试了1024MB.它仍然因内存不足而出现此错误:

Fatal error: Allowed memory size of 1073741824 bytes exhausted (tried to allocate 50331648 bytes) in D:\data\o\WebLibThirdParty\src\PHPExcel\Classes\PHPExcel\Reader\Excel2007.php on line 688

Fatal error (shutdown): Allowed memory size of 1073741824 bytes exhausted (tried to allocate 50331648 bytes) in D:\data\o\WebLibThirdParty\src\PHPExcel\Classes\PHPExcel\Reader\Excel2007.php on line 688

Answer 1

在PHPExcel论坛上有很多关于PHPExcel的内存使用情况的文章; 所以阅读之前的一些讨论可能会给你一些想法.PHPExcel包含电子表格的"内存"表示,并且易受PHP内存限制.

文件的物理大小在很大程度上是无关紧要的...知道它包含多少个单元格(每个工作表上的行*列)更为重要.

我一直使用的"经验法则"平均约为1k/cell,因此5M单元工作簿需要5GB内存.但是,有许多方法可以减少该要求.这些可以组合在一起,具体取决于您需要在工作簿中访问哪些信息,以及您要对其执行的操作.

如果您有多个工作表,但不需要加载所有工作表,则可以使用setLoadSheetsOnly()方法限制Reader将加载的工作表.要加载单个命名工作表:

$inputFileType = 'Excel5'; 
$inputFileName = './sampleData/example1.xls';
$sheetname = 'Data Sheet #2'; 
/**  Create a new Reader of the type defined in $inputFileType  **/
$objReader = PHPExcel_IOFactory::createReader($inputFileType);
/**  Advise the Reader of which WorkSheets we want to load  **/ 
$objReader->setLoadSheetsOnly($sheetname); 
/**  Load $inputFileName to a PHPExcel Object  **/
$objPHPExcel = $objReader->load($inputFileName);

或者,您可以通过传递一组名称来指定几个工作表,其中一次调用setLoadSheetsOnly():

$inputFileType = 'Excel5'; 
$inputFileName = './sampleData/example1.xls';
$sheetnames = array('Data Sheet #1','Data Sheet #3'); 
/** Create a new Reader of the type defined in $inputFileType **/ 
$objReader = PHPExcel_IOFactory::createReader($inputFileType);
/** Advise the Reader of which WorkSheets we want to load **/ 
$objReader->setLoadSheetsOnly($sheetnames); 
/**  Load $inputFileName to a PHPExcel Object  **/
$objPHPExcel = $objReader->load($inputFileName);

如果您只需要访问工作表的一部分,那么您可以定义一个读取过滤器来识别您实际要加载的单元格:

$inputFileType = 'Excel5'; 
$inputFileName = './sampleData/example1.xls';
$sheetname = 'Data Sheet #3'; 

/**  Define a Read Filter class implementing PHPExcel_Reader_IReadFilter  */ 
class MyReadFilter implements PHPExcel_Reader_IReadFilter {
    public function readCell($column, $row, $worksheetName = '') {
        //  Read rows 1 to 7 and columns A to E only 
        if ($row >= 1 && $row <= 7) {
           if (in_array($column,range('A','E'))) { 
              return true;
           }
        } 
        return false;
    }
}

/**  Create an Instance of our Read Filter  **/ 
$filterSubset = new MyReadFilter(); 
/** Create a new Reader of the type defined in $inputFileType **/ 
$objReader = PHPExcel_IOFactory::createReader($inputFileType);
/**  Advise the Reader of which WorkSheets we want to load 
     It's more efficient to limit sheet loading in this manner rather than coding it into a Read Filter  **/ 
$objReader->setLoadSheetsOnly($sheetname); 
echo 'Loading Sheet using filter';
/**  Tell the Reader that we want to use the Read Filter that we've Instantiated  **/ 
$objReader->setReadFilter($filterSubset); 
/**  Load only the rows and columns that match our filter from $inputFileName to a PHPExcel Object  **/
$objPHPExcel = $objReader->load($inputFileName);

使用读取过滤器,您还可以在"块"中读取工作簿,以便任何时候只有一个块驻留在内存中:

$inputFileType = 'Excel5'; 
$inputFileName = './sampleData/example2.xls';

/**  Define a Read Filter class implementing PHPExcel_Reader_IReadFilter  */ 
class chunkReadFilter implements PHPExcel_Reader_IReadFilter {
    private $_startRow = 0;
    private $_endRow = 0;

    /**  Set the list of rows that we want to read  */ 
    public function setRows($startRow, $chunkSize) { 
        $this->_startRow    = $startRow; 
        $this->_endRow      = $startRow + $chunkSize;
    } 

    public function readCell($column, $row, $worksheetName = '') {
        //  Only read the heading row, and the rows that are configured in $this->_startRow and $this->_endRow 
        if (($row == 1) || ($row >= $this->_startRow && $row < $this->_endRow)) { 
           return true;
        }
        return false;
    } 
}

/**  Create a new Reader of the type defined in $inputFileType  **/
$objReader = PHPExcel_IOFactory::createReader($inputFileType);
/**  Define how many rows we want to read for each "chunk"  **/ 
$chunkSize = 20;
/**  Create a new Instance of our Read Filter  **/ 
$chunkFilter = new chunkReadFilter(); 
/**  Tell the Reader that we want to use the Read Filter that we've Instantiated  **/ 
$objReader->setReadFilter($chunkFilter); 

/**  Loop to read our worksheet in "chunk size" blocks  **/ 
/**  $startRow is set to 2 initially because we always read the headings in row #1  **/
for ($startRow = 2; $startRow <= 65536; $startRow += $chunkSize) { 
    /**  Tell the Read Filter, the limits on which rows we want to read this iteration  **/ 
    $chunkFilter->setRows($startRow,$chunkSize); 
    /**  Load only the rows that match our filter from $inputFileName to a PHPExcel Object  **/ 
    $objPHPExcel = $objReader->load($inputFileName); 
    //    Do some processing here 

    //    Free up some of the memory 
    $objPHPExcel->disconnectWorksheets(); 
    unset($objPHPExcel); 
}

如果您不需要加载格式化信息,只需要加载工作表数据,那么setReadDataOnly()方法将告诉读者只加载单元格值,忽略任何单元格格式:

$inputFileType = 'Excel5';
$inputFileName = './sampleData/example1.xls';
/** Create a new Reader of the type defined in $inputFileType **/ 
$objReader = PHPExcel_IOFactory::createReader($inputFileType);
/** Advise the Reader that we only want to load cell data, not formatting **/ 
$objReader->setReadDataOnly(true);
/**  Load $inputFileName to a PHPExcel Object  **/
$objPHPExcel = $objReader->load($inputFileName);

使用单元格缓存.这是一种减少每个单元所需的PHP内存的方法,但速度很快.它的工作原理是以压缩格式存储单元格对象,或者存储在PHP内存之外(例如磁盘,APC,内存缓存)......但是保存的内存越多,脚本执行的速度就越慢.但是,您可以将每个单元所需的内存减少到大约300字节,因此假设的5M单元将需要大约1.4GB的PHP内存.

单元缓存在开发人员文档的4.2.1节中描述

编辑

查看代码,您正在使用迭代器,这些迭代器不是特别有效,并且构建了一组单元数据.您可能希望查看已经内置到PHPExcel中的toArray()方法,并为您执行此操作.另外,请看一下最近关于SO的讨论,关于新的变量方法rangeToArray()来构建行数据的关联数组.

Answer 2

我有与PHPExcel相同的内存问题,实际上所有其他库.正如Mark Ba​​ker建议的那样可以解决问题(缓存也可以),但事实证明内存问题成了时间问题.读写时间是指数级的,因此对于大型电子表格来说,它并不合适.

PHPExcel和其他人不打算处理大文件,所以我创建了一个解决这个问题的库.你可以在这里查看:https://github.com/box/spout

希望有所帮助!

Answer 3

使用PHPExcel时,可以采取许多措施来保留较少的内存.我建议您在修改Apache中的服务器内存限制之前采取以下操作来优化内存使用.

/* Use the setReadDataOnly(true);*/
    $objReader->setReadDataOnly(true);

/*Load only Specific Sheets*/
    $objReader->setLoadSheetsOnly( array("1", "6", "6-1", "6-2", "6-3", "6-4", "6-5", "6-6", "6-7", "6-8") );

/*Free memory when you are done with a file*/
$objPHPExcel->disconnectWorksheets();
   unset($objPHPExcel);

避免使用非常大的Exel文件,请记住文件大小会使进程运行缓慢并崩溃.

避免使用getCalculatedValue(); 阅读细胞时的功能.