Microsoft Sqlserver 2000 versus Oracle

From: Porus H Havewala <porushh_at_bigpond.com>
Date: Wed, 20 Dec 2000 17:27:35 +1100
Message-ID: <3A405157.C03D8BA8@bigpond.com>

Microsoft Sqlserver 2000 versus Oracle
SQL SERVER TECHNICAL LIMITATIONS

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By Faulkner, Kent (kent.faulkner_at_trane.com)

1. Single platform dependancy.

SQL Server is only operable on the Windows platform, and this is a major limitation
for it to be an enterprise solution. Oracle is available on multiple platforms such as
Windows, all flavours of Unix from vendors such as Ibm, Sun, Digital, HP, Sequent,
etc. and VAX-VMS as well as MVS. The multi-platform nature of Oracle makes it
a true enterprise solution.

2. Locking / concurrency

SQL Server has no multi-version consistency model which means that
"writers block readers

and readers block writers" to ensure data integrity. In contrast, with Oracle the rule is
"readers dont block writers and writers dont block readers". This is
possible without
compromising data integrity because Oracle will dynamically re-create a read-consistent
image for a reader of any requested data that has been changed but not yet committed.
In other words, the reader will see the data as it was before the writer began changing
it (until the writer commits). SQL Server's locking scheme is much simpler (less mature)
and will result in a lot of delays/waits in a heavy OLTP environment.

Also, SQL Server will escalate row locks to page level locks when too many rows on
a page are locked. This locks rows which are uninvolved in any updates for no good reason.

3. PERFORMANCE and TUNING

1. No control of sorting (memory allocation)
2. No control over SQL Caching (memory allocation)
3. No control over storage/space management to prevent fragmentation. All pages (blocks) are always 8k and all extents are always 8 pages (64k). This means you have no way to specify larger extents to ensure contiguous space for large objects.
4. No range partioning of large tables and indexes eg. in Oracle a large 100 GB table can be seamlessly partitioned at the database level into range partitions, for eg. an invoice table can be partitioned into monthly partitions. Such partitioned tables and partitioned indexes give performance and maintenance benefits and are transparent to the application.
5. MISSING OBJECT TYPES
6. No public or private synonyms
7. no independent sequences
8. no packages ie. collection of procedures and functions.
9. PROGRAMMING
10. Significant extensions to the ANSI SQL-92 standard which means converting applications to a different database later will be a challenge (code re-write).
11. No JAVA database engine as in Oracle
12. Stored Procedures are not compiled until executed (overhead).
13. No ability to read/write from external files from a stored procedure.

SUMMARY.
SQL Server is clearly positioned between MS-ACCESS and ORACLE in terms of functionality,
performance, and scalability. It makes a work group level solution (small number of users with
small amount of data). Oracle is much more advanced and has more to offer for larger applications
with both OLTP and Data Warehouse applications, and its open-source nature makes it the
most convincing argument for an enterprise. Received on Wed Dec 20 2000 - 00:27:35 CST