| 1. performance
Sybase is quite poor at insert bound applications, mostly due to cache
management; in general Sybase has problems managing larger than 14MB of
cache (these are "Sybase's" words not mine), so any application that
doesn't benefit from cache (i.e., update, insert intensive) will be
quite poor;
2. backup availability
If the question is how to backup, you take image backs along with dumps
(aka transactional snapshots from the log) to recover a database. If
the question is availability in regards to recovery (from a backup), in
database fixes/restores of individual tables/areas is quite difficult;
normally I would restore the entire database. While backup is fairly
understood with this product, RESTORES are black magic.
3. Upgrades
Of what? the base product uses VMSinstall to create a directory tree to
a specified location; one then edits a series of files to complete the
install; this is not concept of 'upgrades' in the sense that images are
patches/replace, you just get new onces. Access to the directory tree
(i.e., V3.2, V4.0, V4.8) is via logical name.
4. System Availability
More often than not, the 'recovery period' (the time the 'other'
machine in a cluster will spend rolling forward the REDO log) is the
real measure of system availability; this processs is called the
companion server who will wake up after being granted an previously
asked for exclusive lock, that was held by the primary dataserver.
5. Cost
~$250K per system and up; What's really weird is that prior to V4.8
(and still valid today I believe) upgrade the host by adding CPUs
doesn't increase your license cost, BUT going from a 6410 -> 6510
(i.e., upgrading per processor performance) does. So, I would expect
most Sybase shops to add more processors, and negatively scale their
performance, rather then upgrading the processor and pay the money.
6. Development effort
This is an API based product; if you like 'em great, if not, too bad.
The biggest problems customer run into is that since this API is HIGHLY
PROPRIETARY (i.e., it's NOT SQL), making logical schema changes /
and design changes, most often involve changing the database and
application, since the interface between the application and server is
a byte stream (known as Tabular Data Stream). You change the order of
a query and you likewise have to change the appliation as well.
/los 'local Sybase honcho, thought not according to Sybase ;-)"
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