php - PDO fetch 语句之间是否存在性能差异？

Question

喜欢

/* Exercise PDOStatement::fetch styles */
print("PDO::FETCH_ASSOC: ");
print("Return next row as an array indexed by column name\n");
$result = $sth->fetch(PDO::FETCH_ASSOC);
print_r($result);
print("\n");

print("PDO::FETCH_BOTH: ");
print("Return next row as an array indexed by both column name and number\n");
$result = $sth->fetch(PDO::FETCH_BOTH);
print_r($result);
print("\n");

print("PDO::FETCH_LAZY: ");
print("Return next row as an anonymous object with column names as properties\n");
$result = $sth->fetch(PDO::FETCH_LAZY);
print_r($result);
print("\n");

print("PDO::FETCH_OBJ: ");
print("Return next row as an anonymous object with column names as properties\n");
$result = $sth->fetch(PDO::FETCH_OBJ);
print $result->NAME;
print("\n");

默认是 FETCH BOTH，我想知道当我要获取大量数据时 FETCH ASSOC 是否更快；还是一样？

谢谢

Answer 1

我想知道这个问题的答案，所以我写了一个快速 benchmark script .

我建议您在自己的服务器上运行此基准测试，但是，这是我设置的典型结果，对于单行结果:

1. PDO::FETCH_ASSOC - 936 毫秒
2. PDO::FETCH_BOTH - 948 毫秒
3. PDO::FETCH_NUM - 1,184 毫秒
4. PDO::FETCH_OBJ - 1,272 毫秒
5. PDO::FETCH_LAZY - 1,276 毫秒

对于大型数据集，这些结果是典型的:

1. PDO::FETCH_LAZY - 5,490 毫秒
2. PDO::FETCH_NUM - 8,818 毫秒
3. PDO::FETCH_ASSOC- 10,220 毫秒
4. PDO::FETCH_BOTH - 11,359 毫秒
5. PDO::FETCH_OBJ - 14,027 毫秒

查看 git hub 上的评论，获取所有行确实改变了测试。