[Tfug] more RDBMS

[jblais]

>
> I'm looking for an inexpensive (computationally)
> way to see if a "database", or, specifically, a
> certain *table* has been *changed* since the last
> time I "noticed" it.  I.e. a way of stat(2)'ing
> it that is *portable* (i.e. lives in SQL land).

Well-
I did a thing where several machines needed up-to-date information from the
db, but requesting stuff could be "slow", and could slow down other
machines.  And several machines could be working on the same set of data at
the same time.  The machines did a cache of part, or all, of the data. Then
as each machine ran, at its own pace and changed it's portion of the data,
it sent the final info to the db server.  The server, or perhaps it was the
machine itself I forget, then broadcast out a short udp message to everyone,
telling them what changed, not all the changes, just enough to be useful.
Each machine listened for what it was interested in (what job it was
running), and ignored the rest.  All the machines always knew enough about
what was going on around them, data wise and processing wise, and when to
update.

The thing is, perhaps the db could broadcast to the clients what all has
happened along with a time signal, and if anyone needs to update their
notion of the world, they can.  I guess it depends a lot on
network/lan/internet whatever you are constrained by (udp- sockets-
whatever).

Joe