Conference ulysse::rdb_vms_competition

1121.0. "Sybase questions" by QUIPU::KULVETE (rebel without a clue) Wed Mar 25 1992 19:01

    I have compiled the following list of "hard" questions to have my
    customer ask Sybase.  My customer is currently an Rdb shop that is
    evaluating Sybase for the following reasons:
        - can put Sybase on RS6000, PCs etc. (but what's important where
          the data is or access to that data from any front-end?)
        - can access Sybase from PC over Novell IPX (our SQL services will
          have this soon)
        - stored procedures and "open server" (I'm pitching ACMS and ACMS
          deskstop with the SQL services future on IPX)
    I want to make sure that all of these questions are valid and won't
    somehow backfire on me.  If you have any other input or suggestions,
    I'd appreciate all the help that I can get.

    Thanks.

    Dave

1.  Is it possible to lose data that has been journaled to memory before it has
been "checkpointed" to disk?  If you checkpoint every transaction, what is the
overhead involved in writing to memory and then to disk all of the time?  Even
if you checkpoint every transaction, isn't there still a window in which the
VAX can go down and you can lose journaled data that is still in memory?

2.  How can you tune the stored procedures.  VPA can be used to figure out that 
a stored procedure is a bottleneck, but how can you figure out what part of the
stored procedure is a problem?

3.  Is the Sybase database functionality first developed on UNIX and then moved
to VMS?  If so, what is the typical lag time for new functionality and bug 
fixes to get into VMS.  Wasn't there a one year lag time between for the latest
version on UNIX and on VMS?

4.  Get a total cost of the Sybase database software (with support and 
maintenance) on a given platform.

5.  Is it possible for us to attend a Sybase database users meeting to hear 
about other customers experiences with Sybase?

6.  Does Sybase on an RS6000 interface with IPX?

7.  Does Sybase have user-based licensing?

8.  Does the Sybase support:
	- row-level locking
	- hashed indexes
	- variable database page size
	- variable index node size
	- variable user and database buffers
	- cursors
	- dynamic space allocation (for when database area becomes full)
	- automatic 2PC (is there a lot of coding to write for 2PC?)
	- automatic locking (or is it manual?)

9.  Is it possible for there to be a time when two database are out of synch
when both the commit server and another server crash at the same time (i.e.
until the commit server is restarted and the other server completes the
outstanding transactions)?

10. Does Sybase have any physical database design tools?

11. Does Sybase integrate with CDD/Repository

12. Does Sybase have a Motif-based graphical schema tool to create database
definitions?

13. Does Sybase have a Motif-based SQL generator?

14. Does Sybase have a tool to help automatically distribute data to remote
databases?

15. Can you typically have other applications running on a machine where the
SQL/Server resides or should it be a dedicated database server?

16. Since the Sybase optimizer is not dynamic (at run-time) how often do you
suggest recompiling the stored procedures to re-optimize them?

17. What monitoring tools can be used to look at database activity (i.e. 
locking, index node updates, processes waiting for data etc.)

18. Are VAX clusters and SMP machines supported by Sybase?

19. Why does Sybase bypass VMS security for database access?

20. How can you prioritize transactions through the SQL/Server?

21. What kind of auditing features are available with Sybase?

22. Can Sybase horizontally partion data or indexes?

23. Can Sybase cluster records from different tables and their indexes on a
single database page to reduce disk I/O?

24. Can Sybase specify what specific disk a table can reside on?

25. Are there any utilities to verify a Sybase database for corruption and
then to fix it?

26. Does Sybase support snapshots to cut down on locking?

27. If a user has privilege to execute a stored procedure, do they also get
automatic privilege to examine the code?

28. Does Sybase have the capability of nesting their triggers?

    

Dave:
	One of the things that sticks out in my mind from a competitive
presentation last July on Sybase was that they had lots of difficulty
producting any reference accounts with databases over 1GB.  Now, I'm not
sure this is even still true (or that I recall it correctly), but if you
are talking about a db size in that range or greater, it certainly shouldn't
hurt to prime your customer to make that request......

Good luck,
Rusty.

Conference DECWET::SYBASE maybe a place to look at.

Some answers after I have attended a Sybase marketing event. I have not had
the time to look at the material I got there.

> 8.  Does the Sybase support:
>	- automatic 2PC (is there a lot of coding to write for 2PC?)

	No automatic 2PC, but it will be there in a future version.

> 12. Does Sybase have a Motif-based graphical schema tool to create database
>     definitions?
> 13. Does Sybase have a Motif-based SQL generator?

	No Motif, if I remember right. They have an own windows interface,
	so they can use it o character cell terminals also. At least one 
	of their tools (it's called DEFT) only runs on MAC's and will run 
	on MS-Windows in the future.

> 18. Are VAX clusters and SMP machines supported by Sybase?

	VAXcluster: One machine is used as a db server, the others are only
	for failover. That's what they call cluster support. I don't know if
	you can use another machine in the cluster for another database.

	SMP: Sybase uses the socalled processor affinitiy. Please have a look
	at my question and the answers in a previous topic in this conference.


Some interesting limitiations I found in a Sybase flyer:

- max. number of dbs in an UPDATE statement: 8
- max. number of open dbs in a query: 16 (depends on available memory)
- max. number of dbs in JOIN: 16
- max. number of column in a table: 250  (sounds good  - for Rdb :-))
- max. number of indices per table: 251 (1 clustered, whatever this means)
- max. number of rows in a multi field index: 16


Hope that helps a bit
-Hans

    re .2 - Clustered means that the records are actually stored in order
    by this particular key.
    
    re .0 - This is a minor point, but Sybase still does not support
    dynamic updates to metadata, either field length changes or the
    addition of records.  Someone, could check this and verify if they have
    more recent information, but for my customer who chose Sybase and has a
    semi-prototyping style of development (they don't mean to, it just
    works out that way 8^) they spend a lot of time copying entire tables
    to other temporary tables just to update or add a single field, and
    then copying them back again.  This can have a significant effect on
    productivity which can impact all of the other development teams trying
    to work with the database.  So, when all else fails, try a little FUD.
    
    							Neil