[Info-vax] Databases versus RMS

[Dirk Munk]

Richard B. Gilbert wrote:
> On 4/17/2012 2:52 PM, JF Mezei wrote:
>> A web forum has been down for over 24 hours now because of a power
>> failure. Seems their database "broke".
>>
>> Since there are few teenagers here, I figured I might get some "senior"
>> opinions.
>>
>> Are database engines so fragile that a power failure will truly wreak
>> havok on a database requiring time consuming work and debugging ?
>
> Some are. Some are not. The expensive ones, e.g. Oracle, should survive
> without problems.
>
> My failing memory recalls something that was called "two phase commit"
> or something like that. You write what you're going to do and then you
> do it. On a successful commit, you mark the transaction complete. If
> your commit fails, you have all the pieces necessary to recover.

Two phase commit was something else as far as I remember. Think of a 
central location where you have a complete database, and a branch office 
with a part of the database that is important for that office. All the 
database actions will be done on the local database of every office, and 
only when a transaction needs to be written to the databases, both 
database instances will communicate to insure that the information in 
both databases stays synchronised.

>
>>
>> Or is this more of a question of young inexperienced web geeks setting
>> up some forum software without selecting the right database options and
>> not realising that letting a database keep everything in cache (writing
>> later when it has time) is a recipe for disaster ?
>>
>
>