PHP echo 5000记录和取消设置
PHP echo 5000记录和取消设置
提问于 2018-12-17 21:59:31
我想回显来自300000个大型数据集的记录。
回显前5000条记录，然后取消设置($data)并迭代，直到mysql表中的记录结束。
就像这样，
1)
for ($i=0; $i < 5; $i++) {
$data = openssl_random_pseudo_bytes(1000000);
echo "peak_memory_usage = ” . memory_get_peak_usage(true) . “\n”;
doSomething($data);
//unset($data);
}
echo “for loop completed, memory now at ” . memory_get_usage(true) . “\n”;
function doSomething($data) {
echo “size:” . strlen($data) . “\n”;
}或者像这样的东西？
2)
nRows = $pdo->query('select count(*) from employees')->fetchColumn();
$users = new ArrayIterator(range(1, nRows)); // nRows are 3000000 test records
foreach(new LimitIterator($users, 0, 50000) as $u) {
echo $u, "\n";
}或
3) @Sameer你是否愿意将你的建议添加到下面的查询中，我可能做了一些错误的事情来添加我们的睡眠-我的编码缺陷，这会导致在添加usleep时出现超时问题。
$data = $DB->query("SELECT * FROM user_details")->fetchAll();
foreach ($data as $row) {
echo $row['username']." -- ID :" .$row['user_id']. " -- FirstName :" .$row['first_name']. "<br />\n";
}第三个选项可以很好地工作，50,000个记录不是很多的RAM负载，而是CPU负载，有没有办法优化它来减少CPU的负载，想象一下如果30个人运行同样的查询，它将占用CPU的最大值？如果我添加usleep(10) -它会回显记录，但在最后会出现一个错误，显示超时。
如有任何建议，欢迎光临。
非常感谢你阅读我的帖子。
- Modified原始帖子的目的是相同的，以减少服务器负载。如果你喜欢我的长篇文章，请投票给我的朋友们，我落后了很多，我想成为future.
的贡献者
我偶然发现了一个通过(Dm4Web)数据加载的令人惊叹的解决方案-令人惊叹的解决方案-但需要添加HTML tables/append或附加结果。
Splitting an AJAX call which returns 5000 rows into multiple AJAX calls with 100 rows
尝试运行以下脚本时，第49行出现错误，未捕获SyntaxError:意外标识：
<!DOCTYPE html>
<html>
<head>
<title>SQL Batch List AJAX and jQuery</title>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.11.0/jquery.min.js"></script>
</head>
<body>
<div id="mainform">
<h2>Fetch REcords 5000 at a time</h2>
<div id="listData">
<div>
<input id="load" name="load" type="button" value ="Load Data">
<input id="cancel" name="cancel" type="button" value ="Cancel">
</div>
</div>
</div>
</body>
<script>
// counter that allows you to get a new set of rows
var step = 0;
// set variable if you want to restrict the number of rows will be loaded
var maxStep = 0;//
// how many rows should be returned
var count = 5000;
// if the cancel button is pressed
var cancel = false;
$(function() {
$('#load').click(function(){
getData();
})
$('#cancel').click(function(){
cancel = true;
})
});
function getData()
{
step++;
//If cancel variable is set to true stop new calls
if(cancel == true) return;
// checks if the variable is set and limits how many rows to be fetched
if(maxStep >0 $$ step >= maxStep)
$.post('ajax.php'
,{
'step':step,
'count':count,
}
,function(data, textStatus, jqXHR){
if(textStatus == "success")
alert("Data: " + data);
/* foreach (data as $row) {
echo $row['username']." -- ID :" .$row['user_id']. " -- FirstName :" .$row['first_name']. "<br />\n";
} */
if(textStatus == "error")
alert("Error: " + jqXHR.status + ": " + jqXHR.statusText);
// when it finishes processing the data, call back function
getData();
}
,'json'
)
}
</script>
</html>
==== ajax.php =====
step = 0;
if(isset($_POST['step'])) $step = (int)$_POST['step'];
$count = 0;
if(isset($_POST['count'])) $count = (int)$_POST['count'];
if($step>0 and $count>0)
{
$offset = ($step-1) * $count;
$limit = $offset.','.$count;
// --------------
// your code here
// --------------
$data = $DB->query("SELECT * FROM user_details LIMIT .$limit")->fetchAll();
$result = mysql_query($sql);
$arr_result = array();
foreach ($data as $row) {
$arr_result[] = $row;
}
$arr_result_enc = json_encode($arr_result);
echo $arr_result_enc;
// echo rows
//echo json_encode($rows);
}方法4)
$query = "SELECT COUNT(*) as num FROM employees";
//$select_run = mysqli_query($conn, $select);
$result = mysqli_query($conn, $query) or die(mysql_error());
$row = mysqli_fetch_array($result);
$itemcount = $row['num']; // Roughly 300,000 total items
$batches = $itemcount / 2000; // Number of while-loop calls - around 120.
for ($i = 0; $i <= $batches; $i++) {
$offset = $i * 2000; // MySQL Limit offset number
$query = "SELECT first_name,last_name FROM employees LIMIT 2500, $offset ";
$result = mysqli_query($conn,$query) or die(mysqli_error($conn));
while ($row = mysqli_fetch_array($result)) {
echo $row['first_name'];
}
echo "<BR>";
echo "Run Number: ".$i."<br />";
echo "<BR>";
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/53816767
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