ca.portal.admin

Different flavors of relational database

Discussion created by ca.portal.admin on May 2, 2006
We did a comparison retrieval between IDMS/SQL (on the mainframe) and
SQL Server (on a Windows server). A database was defined the same way
on both, and loaded with the same data. Queries that used keys (index
or calc) had about the same response time on both. But queries that
generated an area sweep ran noticeably faster on SQL Server, for example
1 second vs. 15 seconds. I am trying to figure out why such a big
difference.

I did not consider the response time for area sweep unreasonable for the
size of the database. But the programmer insisted that it was, and
proved his point with the SQL Server demo. I considered these queries
to be large (for online access), but the SQL Server DBA said that they
are considered small by SQL Server standards. They reported that DB2
(on AIX) could also do similarly large queries with subsecond response
time.

I do realize that there are many differences between the environments,
i.e. hardware, software, operating system, DASD, number of users, etc.
But is there something inherently different about IDMS/SQL that would
cause large queries (area sweeps) to run so much slower than the other
two relational databases?

If anyone else has done similar comparison testing, would you be willing
to share your results?

Kay Rozeboom
State of Iowa
Information Technology Enterprise
Department of Administrative Services
Telephone: 515.281.6139 Fax: 515.281.6137
Email: Kay.Rozeboom@Iowa.Gov
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Re: Different flavors of relational database
"Hi Kay,
Tell us more about how many table occurrences are being read over how many
pages? How is the data clustered on the SQL Server side? SQL Server
certainly can cache / perform look ahead

Are these SQL tables defined as TABLES thru IDMS/SQL? If so, the default
index is still in place?

Mainframe should kick butt on I/O and general responsebut you probably need
to look at what SQL Server is doing via indexes and caching to minimize
I/O.

Regards,
Joe Perkins

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