答案 0 :(得分：39)
我想知道这个问题的答案，所以我快速写了benchmark script。
我建议您在自己的服务器上运行此基准测试，但是，对于单行结果，这是我的设置的典型结果：
对于大型数据集，这些结果是典型的：
查看关于git hub的评论，获取所有行确实改变了测试。
答案 1 :(得分：3)
我想知道当我要获取大量数据时，FETCH ASSOC是否更快;或者他们是一样的？
当您不需要时，不要获取大量数据。就是这样。
一旦你需要它 - 这些方法之间的微观差异将是你最不关心的。
答案 2 :(得分：3)
在另一个答案中发布的基准脚本正在计算prepare（）和execute（）到时间，因此我编写了一个脚本来仅测试获取时间。我有MySQL数据库，有大约100000行真实数据。 LongRow包含TEXT列（每行约4kB数据）。 ShortRow是（每行30个字节）。 FETCH_INTO使用具有所有列属性的预定义类。 PHP版本5.4。 MySQL 5.5.35。这里缺少一件事：一些运行的平均值。
Array
(
[Items: 10] => Array
(
[ShortRow] => Array
(
[FETCH_INTO] => 0.0001068115234375
[FETCH_OBJECT] => 0.00013899803161621
[FETCH_COLUMN (STR8)] => 6.0081481933594E-5
[FETCH_COLUMN (INT)] => 5.8174133300781E-5
[FETCH_NUM] => 9.2029571533203E-5
[FETCH_ASSOC] => 9.8943710327148E-5
[FETCH_BOTH] => 0.00011897087097168
[FETCH_LAZY] => 6.3180923461914E-5
)
[LongRow] => Array
(
[FETCH_INTO] => 0.00012779235839844
[FETCH_OBJECT] => 0.00016498565673828
[FETCH_COLUMN (TEXT)] => 4.9829483032227E-5
[FETCH_COLUMN (INT)] => 4.3153762817383E-5
[FETCH_NUM] => 0.00010180473327637
[FETCH_ASSOC] => 0.00010895729064941
[FETCH_BOTH] => 0.00013399124145508
[FETCH_LAZY] => 4.3869018554688E-5
)
)
[Items: 100] => Array
(
[ShortRow] => Array
(
[FETCH_INTO] => 0.00081610679626465
[FETCH_OBJECT] => 0.0011789798736572
[FETCH_COLUMN (STR8)] => 0.00040292739868164
[FETCH_COLUMN (INT)] => 0.00041294097900391
[FETCH_NUM] => 0.00067806243896484
[FETCH_ASSOC] => 0.00076103210449219
[FETCH_BOTH] => 0.00092482566833496
[FETCH_LAZY] => 0.00043201446533203
)
[LongRow] => Array
(
[FETCH_INTO] => 0.0010471343994141
[FETCH_OBJECT] => 0.0013670921325684
[FETCH_COLUMN (TEXT)] => 0.00037693977355957
[FETCH_COLUMN (INT)] => 0.00030612945556641
[FETCH_NUM] => 0.00079894065856934
[FETCH_ASSOC] => 0.00094914436340332
[FETCH_BOTH] => 0.0011270046234131
[FETCH_LAZY] => 0.00031089782714844
)
)
[Items: 1000] => Array
(
[ShortRow] => Array
(
[FETCH_INTO] => 0.0082287788391113
[FETCH_OBJECT] => 0.0099248886108398
[FETCH_COLUMN (STR8)] => 0.0037147998809814
[FETCH_COLUMN (INT)] => 0.0038070678710938
[FETCH_NUM] => 0.006443977355957
[FETCH_ASSOC] => 0.0070838928222656
[FETCH_BOTH] => 0.008652925491333
[FETCH_LAZY] => 0.0039060115814209
)
[LongRow] => Array
(
[FETCH_INTO] => 0.0092909336090088
[FETCH_OBJECT] => 0.011745929718018
[FETCH_COLUMN (TEXT)] => 0.0031650066375732
[FETCH_COLUMN (INT)] => 0.0025970935821533
[FETCH_NUM] => 0.0068809986114502
[FETCH_ASSOC] => 0.0087978839874268
[FETCH_BOTH] => 0.010183811187744
[FETCH_LAZY] => 0.0026650428771973
)
)
[Items: 10000] => Array
(
[ShortRow] => Array
(
[FETCH_INTO] => 0.067224025726318
[FETCH_OBJECT] => 0.086459159851074
[FETCH_COLUMN (STR8)] => 0.03191089630127
[FETCH_COLUMN (INT)] => 0.031462907791138
[FETCH_NUM] => 0.047988891601562
[FETCH_ASSOC] => 0.05333399772644
[FETCH_BOTH] => 0.065713882446289
[FETCH_LAZY] => 0.028834819793701
)
[LongRow] => Array
(
[FETCH_INTO] => 0.12389183044434
[FETCH_OBJECT] => 0.15812706947327
[FETCH_COLUMN (TEXT)] => 0.03816294670105
[FETCH_COLUMN (INT)] => 0.035914897918701
[FETCH_NUM] => 0.1117901802063
[FETCH_ASSOC] => 0.10923099517822
[FETCH_BOTH] => 0.12394094467163
[FETCH_LAZY] => 0.030914068222046
)
)
)
这也是一个代码：
//Code is missing connect to DB
header('Content-Type: text/plain');
class testModel1 {
public $id;
public $invoice;
public $transaction;
public $creditedInvoice;
public $amount;
public $payment_type;
public $currency;
public $created;
public $timestamp;
}
class testModel2 {
public $id;
public $cid;
public $c_amount;
public $object;
public $person;
public $date;
public $type;
public $invoice_type;
public $version;
public $templateInvoice;
public $account;
public $variable_symbol;
public $number;
public $accounting_year;
public $amount;
public $currency;
public $comment;
public $data; //is a text column (avg size about 4kB)
public $created;
public $modified;
public $timestamp;
}
$items = array(10,100,1000,10000);
foreach($items as $item) {
$ivStmt = $pdo->prepare("SELECT * FROM `invoices_paying` LIMIT $item");
$ivStmt->execute(array('items'=>$item));
$out = array();
$testModel1 = new testModel1();
$ivStmt->setFetchMode(PDO::FETCH_INTO, $testModel1);
$start = microtime(true);
while($id = $ivStmt->fetch()) {
}
$end = microtime(true);
$out['FETCH_INTO'] = $end-$start;
$ivStmt->execute(array('items'=>$item));
$start = microtime(true);
while($id = $ivStmt->fetchObject()) {
}
$end = microtime(true);
$out['FETCH_OBJECT'] = $end-$start;
$ivStmt->execute(array('items'=>$item));
$start = microtime(true);
while($id = $ivStmt->fetchColumn(5)) {
}
$end = microtime(true);
$out['FETCH_COLUMN (STR8)'] = $end-$start;
$ivStmt->execute(array('items'=>$item));
$start = microtime(true);
while($id = $ivStmt->fetchColumn(0)) {
}
$end = microtime(true);
$out['FETCH_COLUMN (INT)'] = $end-$start;
$ivStmt->execute(array('items'=>$item));
$start = microtime(true);
while($id = $ivStmt->fetch(PDO::FETCH_NUM)) {
}
$end = microtime(true);
$out['FETCH_NUM'] = $end-$start;
$ivStmt->execute(array('items'=>$item));
$start = microtime(true);
while($id = $ivStmt->fetch(PDO::FETCH_ASSOC)) {
}
$end = microtime(true);
$out['FETCH_ASSOC'] = $end-$start;
$ivStmt->execute(array('items'=>$item));
$start = microtime(true);
while($id = $ivStmt->fetch(PDO::FETCH_BOTH)) {
}
$end = microtime(true);
$out['FETCH_BOTH'] = $end-$start;
$ivStmt->execute(array('items'=>$item));
$start = microtime(true);
while($id = $ivStmt->fetch(PDO::FETCH_LAZY)) {
}
$end = microtime(true);
$out['FETCH_LAZY'] = $end-$start;
$table['Items: '.$item]['ShortRow'] = $out;
}
foreach($items as $item) {
$ivStmt = $pdo->prepare("SELECT * FROM `invoices` LIMIT $item");
$ivStmt->execute(array('items'=>$item));
$out = array();
$testModel2 = new testModel2();
$ivStmt->setFetchMode(PDO::FETCH_INTO, $testModel2);
$start = microtime(true);
while($id = $ivStmt->fetch()) {
}
$end = microtime(true);
$out['FETCH_INTO'] = $end-$start;
$ivStmt->execute(array('items'=>$item));
$start = microtime(true);
while($id = $ivStmt->fetchObject()) {
}
$end = microtime(true);
$out['FETCH_OBJECT'] = $end-$start;
$ivStmt->execute(array('items'=>$item));
$start = microtime(true);
while($id = $ivStmt->fetchColumn(17)) {
}
$end = microtime(true);
$out['FETCH_COLUMN (TEXT)'] = $end-$start;
$ivStmt->execute(array('items'=>$item));
$start = microtime(true);
while($id = $ivStmt->fetchColumn(0)) {
}
$end = microtime(true);
$out['FETCH_COLUMN (INT)'] = $end-$start;
$ivStmt->execute(array('items'=>$item));
$start = microtime(true);
while($id = $ivStmt->fetch(PDO::FETCH_NUM)) {
}
$end = microtime(true);
$out['FETCH_NUM'] = $end-$start;
$ivStmt->execute(array('items'=>$item));
$start = microtime(true);
while($id = $ivStmt->fetch(PDO::FETCH_ASSOC)) {
}
$end = microtime(true);
$out['FETCH_ASSOC'] = $end-$start;
$ivStmt->execute(array('items'=>$item));
$start = microtime(true);
while($id = $ivStmt->fetch(PDO::FETCH_BOTH)) {
}
$end = microtime(true);
$out['FETCH_BOTH'] = $end-$start;
$ivStmt->execute(array('items'=>$item));
$start = microtime(true);
while($id = $ivStmt->fetch(PDO::FETCH_LAZY)) {
}
$end = microtime(true);
$out['FETCH_LAZY'] = $end-$start;
$table['Items: '.$item]['LongRow'] = $out;
}
print_r($table);
答案 3 :(得分：2)
答案 4 :(得分：-2)
最后的回答是愚蠢的（“不要获取....”）：如果你必须为大表或接口dbs表转换数据怎么办？
我更改了上面的基准测试代码，因为它没有正确测试IMHO（每个循环一个单独获取是不够的;-)），我将其替换为10000个记录x每个获取类型100个循环。
我添加了Fetch_class这是我自己的问题。 我添加了一个真正的类来确定后一个测试是否正确。
结果（已排序）：
Array
(
[Lazy] => 88.43896484375
[Num] => 281.11694335938
[Assoc] => 310.59375
[Class] => 384.8310546875
[Obj] => 395.36401367188
[Both] => 411.62109375
)
懒惰值不完整，因为没有访问权限。 但“两者”实际上 HAS 影响
这是修改后的要点modified Benchmark code