[Zope-DB] SQL optimisation: follow up

M.-A. Lemburg mal@lemburg.com
Tue, 12 Nov 2002 12:23:23 +0100

mlist@fissgus.de wrote:
>>-----Original Message-----
>   > From: mal@lemburg.com [mailto:mal@lemburg.com]
>   > 
>   > Dieter Maurer wrote:
>   > > M.-A. Lemburg writes:
>   > >  > Funny that nobody ever considers using the open-source SAP DB.
>   > >  > That's a full-blown RDBMS with a long history of being reliable
>   > >  > and fast.
>   > > A colleague made some tests (not completely 
>   > systematically, not a complete
>   > > test suite).
>   > > SAP DB performed considerably worse than PostgreSQL in 
>   > these tests,
>   > > especially when the amount of data grew.
>   > 
>   > Strange, my observation is that SAP DB does really well on large
>   > data (after all, it was designed for that). Unlike MySQL large
>   > result sets don't lower the performance.
> as Dieter pointed out: not systematically tested, no complete test
> suite; 
> if interested, some details here:
> http://listserv.sap.com/pipermail/sapdb.general/2002-August/013816.html

Hmm, the fact that SAP DB got slower during the process
indicates that there was a resource problem. If you don't
commit your work every now and then, then the transaction log
will fill up considerably and this results in poor performance.
The same is probably true for PostgreSQL.

MySQL performs in auto-commit mode, so doesn't have this

>   > > He also had some problems with the ODBC drivers and the SAP DB
>   > > admin tool.
>   > 
>   > If you don't like the ODBC drivers (which aren't that bad compared
>   > to those of several other vendors), you can still use the SAP DB
>   > native Python interfaces.
> sure, but for our needs, the ODBC driver is important: many people
> access 
> the databases from the 'windows-world'

That tells me that you're comfortable with the PostgreSQL
ODBC driver. Perhaps I should have a look again...

>   > 
>   > > He was transformed from a SAP DB enthusiast to an SAP DB doubter.
> Maybe thats a little bit too harsh :-)
> At the time, the decision which database to use had to be made, I didn't
> feel 
> comfortable enough to say 'sapdb is *the* database to use'.
> I still 'like' sapdb and I think they did a great job. Especially their 
> mailinglist is very good and usually the sapdb-people answer questions 
> very fast and provide helpfull information.
> When I find the time, I will definitively give sapdb a new try.
>    > Anyway, just thought I'd mention SAP DB here,
> I guess, no matter which database you use, it ends up to somthing like:
>   - all off them have their benefits (if you know what you are doing :-)
>   - sooner or later you will receive a severe blow

All true :-)

Even Oracle crashes every now and then. BTW, one thing to never
do with SAP DB is to switch off power... on at least one machine
we are using this corrupts the indexes.

Marc-Andre Lemburg
CEO eGenix.com Software GmbH
eGenix.com -- Makers of the Python mx Extensions: mxDateTime,mxODBC,...
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