Hi - I previouslu wrote up how we use PostgreSQL
as an entry level DB for our low-med end customers
and that we use Oracle for the more high end customers.
This thread has brought out a key point, the larger
customer will not worry about a few $100k in the
context of their multi $million IT spend. Oracle
does provide the 'warm and fuzzy' feelings senior
non IT management seem to need.
This does not mean that PostgreSQL is not a supurb
option.
Another area that Oracle are marketing very heavily
is RAC (real application clusters). For those that
don't know, Oracle have incorporated the DLM (distributed
lock manager) from Compaq (orgiginally from Digital
VAX/VMS (OpenVMS)). When using Compaq Tru64 unix
and Oracle it is possible to build a zero down time
system (except for Oracle software upgrades, Compaq Tru64
has cluster rolling upgrades).
Oracle tell us that they will support cluster
rolling upgrades in 10i.
The point about DLM is that all machines in a cluster
write to the shared disks, only lock traffic (not data)
go over the network, thus achieving nearly linear scaling.
A clustered Oracle/Compaq setup appears to be a single
database instance.
Food for thought for the PostgreSQL developers!
PostgreSQL with DLM (clustering) !!!
Regards, Kym Farnik (mailto:kym@recalldesign.com)
-- Recall Design http://www.recalldesign.com
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