Backup

[Mr. Bart Pietercil]

Hi Ivan,
On 13-feb-08, at 22:26, Ivan Smahin wrote:

> 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.
right

>
>
> 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.).
>

This is what I mean. The scheduler takes the mutex when performing the  
backup. So when , while the backup is being created (may take a few  
seconds), ANOTHER client (in this case vPHP) wants to acces the kernel  
(perform an insert let's say) what will happen ?

Insert will fail ? Is there an error thrown ?

TIA

Bart