Dynaset vs Snapshot + Jet Engine included ? 
Author Message
 Dynaset vs Snapshot + Jet Engine included ?

Hi everybody,

I have 2 questions :

1) I tried to read data using CDaoRecordset, and using the two possible ways
of opening the DaoRecordset : Dynaset & Snapshot. In both cases, I open the
recordset and then move one by one from the first to the last record. I was
expecting of better performance when using a snapshot type recordset, but I
observe exactly the same durations (I read from an Access table which
contains 50.000 records). In both cases, It takes about 12 seconds ! Is it
normal ?

2) I was wondering if the Microsoft Jet Engine is included in windows
itself, i.e. can I rely on its presence if I have an application that makes
use of it. Or is it only installed when you install Access ?

Thank you very much for any kind of advices you could provide me !

Fred



Thu, 20 Mar 2003 03:00:00 GMT  
 Dynaset vs Snapshot + Jet Engine included ?
There are many reasons why reading all records out of 50000 may take just as
long with a snapshot as with a dynaset.

DB performance is usually the main performance issue with applications as it
is also usually the slowest component (IE it is on disc).
However in your case reading 50000 records like this may be normal, but more
usually reading all records in sequence like this is not the norm.
There are many articles in MSDN and throughout the web on optimising db
access. I suggest that when you write your application you do so with the
view to 'profiling' it when it is stable. Profiling is about measuring which
parts of your application take the longest to run and / or are run most
often - this leads down the *most* productive way of tuning an applications
performance.

Compared to other dbms, DAO is fast.

The jet drivers are freely dsitributeable - latest versions are in the file
MDAC_TYP.exe available from www.microsoft.com\data
In general, any setup program you write - and any software you start writing
should use the most recent 'stable' version. For this reason the install
from MS mentioned above should be used both for yourself and in your
installation package.

- Tim


Quote:
> Hi everybody,

> I have 2 questions :

> 1) I tried to read data using CDaoRecordset, and using the two possible
ways
> of opening the DaoRecordset : Dynaset & Snapshot. In both cases, I open
the
> recordset and then move one by one from the first to the last record. I
was
> expecting of better performance when using a snapshot type recordset, but
I
> observe exactly the same durations (I read from an Access table which
> contains 50.000 records). In both cases, It takes about 12 seconds ! Is it
> normal ?

> 2) I was wondering if the Microsoft Jet Engine is included in windows
> itself, i.e. can I rely on its presence if I have an application that
makes
> use of it. Or is it only installed when you install Access ?

> Thank you very much for any kind of advices you could provide me !

> Fred



Tue, 25 Mar 2003 03:00:00 GMT  
 Dynaset vs Snapshot + Jet Engine included ?


Fri, 19 Jun 1992 00:00:00 GMT  
 Dynaset vs Snapshot + Jet Engine included ?
First, thanks for your answer !



Quote:
> There are many reasons why reading all records out of 50000 may take just
as
> long with a snapshot as with a dynaset.

I don't understand them, because if I look at the MSDN, I can read that
opening a recordset as a snapshot means that you are loading in memory not
only the primary key of the records found, but the whole records, so that
you can access them after more efficiently. My thought was that with a
snapshot I could spend more time to opening it thant with a Dynaset, but
that then I could read each record from memory (I thought that "Snapshot"
meant that all the records were already fully loaded in memory during
opening). Apparently I must have misunderstood something .... ?

Since I posted my original question, I've developped a simple cache system
that allows me to load all the records in memory, exactly as I wanted :-)
So I think my problem is now solved. But I'm still wondering what I've
missed reading the docs....

Fred



Fri, 28 Mar 2003 08:37:57 GMT  
 
 [ 4 post ] 

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