MySQL time_zone'当前会话'-是IP还是连接？

Question

I have a project that is, intermittently, changing the time_zone value from a user defined value, to SYSTEM, and I am trying to determine if MySQL considers 'the current session' ( MySQL TimeZone ) the connection, or, the workstation IP that the connection is coming from.

Basically, if it's not per connection, then something else is connecting to MySQL and changing the time_zone value back to SYSTEM, which is then having an impact on my already connected software.

If it is per connection, then I am back to trying to figure out WHERE the time_zone is being reset.

For further info, my project is written in Delphi XE3, using the MyDAC components for DB connections. When the project loads, I read a connection file and, if there is a time_zone string set, I execute the 'Set Time_zone' query. The connection stays active through-out the applications run lifetime and is global to the application (ie I don't create/connect other connections from this application to the DB).

Thanks for your assistance!

Answer 1

A MySQL session corresponds to a connection.

The MySQL server automatically disconnects idle sessions after a timeout, based on the value of the system variable wait_timeout , which defaults to 28800 seconds (8 hours). It sounds like Delphi is automatically reconnecting your session, but per-session settings will be lost when this happens.

You should change your application so that it sends the timezone setting if it has been idle for a long period of time. You could also increase the wait_timeout (the maximum value is 2147483, 24.85 days).