PHP无法关闭Mysql连接并达到最大连接数

Question

I have a site that is about 6 years old, and in the last 6 months, we have been getting the same issue over and over with maxing out the mysql connections.

Now every couple of days the site becomes unavailable because there are no sql connections left. As it's on a shared server, I need to get the host company to flush the connections.

Here's what I tried:

• Made sure every page now has a close on it
• Upgraded to PHP7 and converted to mysqli
• Pulled my hair out

Everywhere I look, it says not to use Persistant connections - I am not explicitly using them - and that PHP will automatically release connections after the page completes - hmmm...

The host company is usually really helpful, but not over this. So I have 2 questions...

1. What is causing the connections to not close either on my mysqli_close() or on PHP exit? Perhaps pages are aborting or too slow and failing?

2. Why don't the connections close themselves... It can be hours later that I report it to the host company and they flush the connections... Why are they not bring tidied up? In the mean time the site is unavailable...

Please help..

Cris.

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Ah... I have just read the host company responses more clearly... (it's been a hectic few days) They say "The issue that is the database server on the shared hosting platform is designed to lock the database once it hits it's maximum allowed connections, so it never closes any connections once it hits 25 simultaneous connections. "

So the question is why am I hitting 25 connections? Is is that I'm holding connections open for slow loading pages and so limiting the number available?

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Answer 1

whenever you open a mysqli connection

$mysqli = connect_db();

you have to explicitly close it or they linger around and mysql server eventually is unhappy

$mysqli->close();

While explicitly closing open connections and freeing result sets is optional, doing so is recommended. This will immediately return resources to PHP and MySQL, which can improve performance. http://php.net/manual/en/mysqli.close.php