Re: Oracle and SQL Server

On 4 Jan 2002 09:23:48 -0800, garrickb_at_software360.com (Garrick Bigwood) wrote:

>Thanks for above comments. I take point about comparing apples and
>oranges but test results such as these are the things that management
>decisions will be/are being based on so I am trying to make the best
>comparison I can.
>Regarding SGA I have been doing test with this at 44MB this gave me
>hit ratio of .99, I tried raising SGA to 300MB which did give some
>improvement in times to between 35-40 secs with hit ratio of .99.
>Other details: I am using Solaris DirectIO option which did give
>significant improvements especially for redo logs, the test table I
>use has 5 cols one of which is PK(index in separate tabspace)
>populated from sequence, table in own tabspace < 12MB, redo logs 150
>MB on one disk(log buffer 160k), datafile and Rollback segs(extents
>20MB) on the other two disks, I do COMMIT after Update completes but I
>find all the writing takes place before this, during the Update I can
>monitor with iostat and writing starts with start of Update and
>finishes with end of job, COMMIT only produces small amount, I guess
>Checkpointing, most of writing is to Rollback(from V$Filestat).
>I have run the tests on SQL Server installed on my PC (450CPU, single
>disk and 128 Mb Ram), which maybe gives a better comparison the
>smaller memory forcing it to do some I/O during TX, this gave similar
>results(40 secs or so) to Oracle on the Sun server but I'm not sure if
>this is being unfair to SQL Server also unrealistic regarding hardware
>market. Maybe its that the performance for these tests from both
>databases is pretty similar but SQL Server is better at smaller table
>caching and SQL Server is on the latest hardware and Oracle on some
>fairly old hardware.
>
>Garrick

20 Mb extents for rollback is way too big, as Oracle will try to cache them in SGA

Hth

Sybrand Bakker, Senior Oracle DBA

To reply remove -verwijderdit from my e-mail address Received on Fri Jan 04 2002 - 17:43:05 CST