[vworld-tech] Database usage

Brian Hook hook_l at pyrogon.com
Tue Feb 10 10:53:46 PST 2004

> Either is good, amazingly large/complex web sites are run straight
> out of a db (with a cache layer for common elements).

Right, there was a "database is God" thread on Mud-dev a while ago on 
this subject, but my gut instinct is that hammering the DB for every 
object access would be bad with, say, 1000 players connected, but 
since I don't have the ability to connect 1000 players and measure the 
results, I'd be curious if others that are doing "database is God" 
schemes are having okay performance.

> If your memory footprint can be huge, consider a serialization
> method so objects can 'save themselves' and only hit the db on
> instantiation/disposal.

Yeah, memory usage is up to physical limit of the machine (2GB right 
now, but easily expanded if we need to go to 64-bit).  The cache is a 
real basic unbounded one, a la:

function Room.get( room_id )
   if Room.rooms[ room_id ] ~= nil then
      return Room.rooms[ room_id ];

   Room.rooms[ room_id = TRAP_load_room( room_id )
   return Room.rooms[ room_id ]

So first time use will hit the DB.  I store very few instances in the 
DB, the only thing persisted are players and their contents.  
Everything else is cleared and reset on a server restart.

At the limit the cache will hold the entire DB in memory, which may or 
may not be a problem (I haven't had a chance to sit down and work out 
the typical memory footprint for a room, item, mob, etc.).



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