Backup

[Ivan Smahin]

Hello Mr.,

Wednesday, February 13, 2008, 10:56:04 PM, you wrote:

> Hi List,Ruslan,

> Does anybody care to explain to me what exactly happens when a VServer
> is making a backup. I have a VServer on an interval of 1 hour. This is
> working flawless.

> However I'm wondering what is happening while the VServer is making a
> backup. Does it become unresponsive for clients making an attempt to  
> talk to the database?

Well, obviously you mean not backup but scheduler - right?
Just the most wanted command to run by schedule is backup.

One of the service thread inside the server is for scheduler purpose.
You    are   preparing   event  via  SQL  and  then  vServer scheduler
calculates the nearest time to wake up and perform the task defined in
that event. So most of the time scheduler thread sleeps.
Awaking, it performs the task very similar to regular client - so during
task execution  kernel is locked out (but server is still able to accept commands
from  another clients. The deal is - almost any command goes to kernel
-  so  most  of  the  client requests will be waiting for kernel mutex.).

So  I  would  say  yes  -  in this meaning server becomes unresponsive
until scheduled task is finished.

Don't worry - any particular command can not be interrupted.

> Does a client time-out ?

No  -  it is similar but not a client. Scheduler is free of timeouts.
The  only  purpose of timeouts is - disconnect clients which block some
records and go out for some coffee.

> Bit at loss, here, so I'll first wait for someone to shed some light  
> and then I'll come back with some more questions.

Welcome


-- 
Best regards,
Ivan Smahin 
Senior Software Engineer
Paradigma Software, Inc
Valentina - The Ultra-Fast Database
http://www.valentina-db.com