DBMS, August 1997
I found Charles Thompson's article "Database Replication" (DBMS, May 1997, page 76) very informative. He seems to have a very good, sound knowledge of different DBMSs, especially Oracle, Sybase, and Microsoft SQL Server. His analysis is right on, and I agree with him especially when he says "replication is serious business" and requires careful planning.
We are using Microsoft SQL Server 6.5 and using the replication feature to distribute our database to multiple sites (it's been in production for about a year). I found SQL Server 6.5 to be a very good product, and I certainly recommend it over Sybase for small- to medium-sized companies that plan to use replication because: a) it's easy to use, b) replication is a built-in feature, not a separate product, and c) the pricing is fair.
Mind you, I have also worked extensively with Sybase and other DBMSs such as Adabas and DB2, and not much with the Sybase replication server, but I do understand the architecture behind it.
I wanted to share my thoughts with someone who understands the technology and its challenges and shortcomings.
Kamal Hassan
Ontario, Canada
I'm glad to hear from a happy Microsoft user. I can get pretty negative about SQL Server sometimes!
I would just caution you against justifying the use of Microsoft on ease of use, packaging, and cost. The competitors, including IBM Corp. and Informix Software Inc., now price their Windows NT products very close to Microsoft Corp., so pricing is not such an issue. Sybase Inc. charges extra for replication, and Oracle Corp. only bundles in basic snapshot replication, but it's worth comparing the total cost for product, support, and upgrades over a few years.
All of the competitors offer easy-to-use administration tools, and Sybase's technology is very similar to Microsoft's. The only thing Sybase doesn't have is the tight integration with Windows NT, which can be a negative if you think you may need to scale past the limitations of Windows NT.
My real complaint with Microsoft is the quality. My colleagues and I have not had good luck with SQL Server replication. You might want to take this into consideration when planning your database's future.
-- Charles Thompson