迁移到新服务器，性能降低

Question

I just moved my website to another server with upgraded specifications but I got stuck with the slow performance.

it was working great on old server but somehow on new server, when I do php user login, server responding me in 5 minutes! yeah, php executation takes 5 minutes long. Without logging in (using php sessions) it's working as expected. I'm using php+mysqli.

here is the comparision of two servers:

Old

• Apache Version: Apache/2.2.15 (CentOS)
• PHP Version: 5.4.0
• MySQL version: mysqlnd 5.0.10 - 20111026 - $Revision: 323634 $

New

• Apache Version: Apache/2
• PHP Version: 5.4.3
• Database client version: libmysql - 5.1.62

What should I do? I can't really figure out what's going on..

thank you.

Answer 1

First, try actually measuring calls as others have already said to narrow down the issue.

For instance the part where you connect to the database engine.

Could it be that the MySQL server is running on a different machine?

If so, there could be a reverse DNS problem where the MySQL server has trouble finding out about the name of the calling client.

Or you could face an issue where the MySQL client tries an IPv6 connection twice before it finally decides to fall back to a trusty IPv4 address. This process will easily take 1 second or more!

Try to connect to a normal IPv4 address instead of using a dynamic host name temporary and see if it instantly becomes faster.