Question

我在结果集中有4000行的查询。如果我在像Heidisql这样的查询浏览器中执行此查询，我会在0.5秒内获得所有4000行。如果我在我的Internet浏览器中查看Query:alter Table 'TableName' drop constraint PK__TableName__30242045，我会在30秒内获得所有数据。这是一个很大的区别！我试过mysqli和PDO这是同样的问题。这是一个简单的查询，来自twotable（带有左连接），有18列。我的查询中有一个位置，所有标准都被编入索引（2索引！）我有一个带有php 5.3的mysql 5.1

这里是代码：

print_r($result);

这是EXPLAIN的结果：

$db_handle->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$db_handle->setAttribute(PDO::ATTR_AUTOCOMMIT, false);
$time_start = microtime(true);

$sqlCFf = "
SELECT ....
";
$result_set = $db_handle->query($sqlCFf);

$result = $result_set -> fetchAll();
print_r ($result);

$time_end = microtime(true);

$time_res = $time_end - $time_start;

如果有人想要在PHP中更快地找出输出？

提前THX

Answer 1

使用EXPLAIN

('Bad input argument to theano function with name "<stdin>:1"  at index 0(0-based)', 'Wrong number of dimensions: expected 2, got 1 with shape (2,).')

了解EXPLAIN的输出

EXPLAIN SELECT * FROM tablename

Answer 2

据我所知，任何编程语言的打印结果都会耗费大量的资源/时间。

从你的代码：

$result = $result_set -> fetchAll();
print_r ($result);
//you try to record the end time after printing then it will took longer and not a reliable approach
$time_end = microtime(true);

尝试重新安排这样的代码：

$result = $result_set -> fetchAll();

//put it here, then it will record the end time before printing, which is the right way to benchmark
$time_end = microtime(true);
print_r ($result);

mysql结果集在php输出中非常慢

2 个答案: