| 1) I don't believe that INGRES supports VAX clusters -- at least it doesn't as
well as Rdb/VMS does. For example, can people on one node in a cluster access
the database concurrently with other people on other nodes in the same cluster
in an efficient manner? Or do things get funnelled through a single process
that can cause a bottleneck? Will the addition of a node in the cluster allow a
reasonable level of scaling -- i.e. increase the number of users supported
and/or the transaction throughput?
2) I believe that INGRES has some surprisingly small limits on things like
the number of fields in a table, the max size of a field in a table, the total
size of a row in a table. The Rdb limits are much greater.
3) Rdb/VMS provides much more flexibility in how data is physically partitioned
across disks, which can allow you much more control over performance.
4) I don't think INGRES integrates at all with *any* of our CASE/VAXset tools,
the most visible of which is the CDD.
5) Rdb/VMS can change most things in the database dynamically. I believe
that INGRES forces you to take down the database from normal user access on a
regular basis, and restructure it offline. This includes the reoptimization of
queries, I believe.
6) Rdb/VMS has online backup. I don't believe that INGRES does.
7) Rdb/VMS has RMU, which allows you to find out all kinds of statistics about
your database, online. I don't think INGRES has anything equivalent.
Of course, there are different versions of INGRES -- I presume that INGRES are
pitching their 6.2 (6.3?) version? The answers to these questions will
probably vary depending on what version you're talking about.
There are papers that compare INGRES with Rdb/VMS on a much more detailed level.
Perhaps someone else can point you at them? Michael Booth?
Hope this helps.
Bryan
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| Take a look at nova::pm01:[booth$public]rdbms_features_grid.* (or
something like that).
But, summarily, they don't the online, incremental, multistream
backup capabilities (read "availibility") that Rdb does,
they don't having the levels (variable table page size, database
page size, index page size, both by-index and by-database) of db
tuning that Rdb does. And they don't have database-level integrity
or triggers.
-at least last time DBS marketing checked...
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