[MUD-Dev] Comments on the DB layer

[clawrenc at cup.hp.com]

In <9705071500.7z9n at ami-cg.GraySage.Edmonton.AB.CA>, on 05/07/97 
   at 08:20 PM, cg at ami-cg.graysage.edmonton.ab.ca (Chris Gray) said:

>[Chris L:]

>:Now to go argue with myself and see if I really want some form of
>:query support for the DB.  The appeal of having an admin able to do
>:something like:
>:
>:  Show me all the users who killed mobile XXX in the last week,
>:  cross referenced with a list of all the weapons and spells
>:  they used in their successful attacks.
>:
>:is undeniable.

>Hmm. Methinks you are stepping beyond the bounds of what most people
>would think of as "a database to support a MUD system". 

Yup.  You bet.

>To do this
>you would have to never actually delete any database entity, so that
>all of the historical states are preserved. Your database would
>explode quickly! 

My idea is to have the DB constantly trimmed back to a configured "max
age".  That max age could be minutes, days, weeks, or even
months/years if you have enough disk space.  This (obviously) time
limits the queries that could be done. but does also allow for a
certain level of recovery that is otherwise not possible.

eg:

  A core object on which thousands of other objects depend 
  is accidentally deleted.

  How do you recover?

>The next step of course is to not discard records
>produced by threads failing and being rescheduled - then you can find
>out how often you are getting "update conflicts" in your system.

Its easier to write a simple log for that sort of thing, indicating
rescedule rates and patterns of repeat offenders.  Best case would be
to insert a generic callout that an admin client can plug into to
monitor what's going on and create/store/manage its own DB for the
events.

--
J C Lawrence                           Internet: claw at null.net
(Contractor)                           Internet: coder at ibm.net
---------------(*)               Internet: clawrenc at cup.hp.com
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