PHP mySQL-何时是断开数据库连接的最佳时间? [英] PHP mySQL - When is the best time to disconnect from the database?

问题描述

我使用惰性连接来连接数据库对象中的数据库.这基本上意味着，在处理完第一个查询之前，它不会调用mysql_connect()，并且此后它随后将跳过重新连接.

I use lazy connection to connect to my DB within my DB object. This basically means that it doesn't call mysql_connect() until the first query is handed to it, and it subsequently skips reconnecting from then on after.

现在，我的数据库类中有一个名为disconnectFromDB()的方法，该方法几乎调用了mysql_close()并设置了$_connected = FALSE(因此query()方法将知道再次连接到数据库).应该在每个查询之后(作为私有函数)还是通过对象在外部调用此方法...因为我在想类似的东西(代码仅是示例)

Now I have a method in my DB class called disconnectFromDB() which pretty much calls mysql_close() and sets $_connected = FALSE (so the query() method will know to connect to the DB again). Should this be called after every query (as a private function) or externally via the object... because I was thinking something like (code is an example only)

$students = $db->query('SELECT id FROM students');

$teachers = $db->query('SELECT id FROM teachers');

现在，如果它在每次查询后都关闭，那么这会减慢很多速度，而不是我将这行添加到末尾

Now if it was closing after every query, would this slow it down a lot as opposed to me just adding this line to the end

$db->disconnectFromDB();

还是我应该在页面末尾的上方添加该行?

Or should I just include that line above at the very end of the page?

两者都有哪些优点/缺点?在您的情况下，哪种方法最有效?忘记关闭mySQL连接真的有什么不对劲，除了会损失一点性能之外?

What advantages/disadvantages do either have? What has worked best in your situation? Is there anything really wrong with forgetting to close the mySQL connection, besides a small loss of performance?

感谢您抽出宝贵的时间来回答.

Appreciate taking your time to answer.

谢谢！

推荐答案

据我所知，除非您使用持久连接，否则您的MySQL连接将在页面执行结束时关闭.

As far as I know, unless you are using persistent connections, your MySQL connection will be closed at the end of the page execution.

因此，您调用断开连接将不会添加任何内容，并且由于您执行的是惰性连接，如果您或其他开发人员出错并在错误的时间断开连接，则可能会导致创建第二个连接.

Therefore, you calling disconnect will add nothing and because you do the lazy connection, may cause a second connection to be created if you or another developer makes a mistake and disconnects at the wrong time.

鉴于此，我只允许我的连接自动关闭.您的页面应该能够快速执行，因此在短时间内保持连接不会造成任何问题.

Given that, I would just allow my connection to close automatically for me. Your pages should be executing quickly, therefore holding the connection for that small amount of time shouldn't cause any problems.

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