Re: Use of SetResultSizes() the last

Question

Hi again,
May be to be tested with the SetMaxSize : DBSession.SetResultSize
Here is an extract of the help :
"You use the SetResultSizes method after setting the maximum size of any
columns using the SetMaxSize method or MaxRows attribute (both are in
the DBDataSet class), to set the expected size of any BinaryData objects
to be fetched. The size should be set after invoking the OpenCursor
method and before invoking the first FetchCursor."
Hope this helps,
Daniel Nguyen
Freelance Forte Consultant
URL : http://perso.club-internet.fr/dnguyen/
Joseph Mirwald wrote:
>
Hello Daniel,
i am very happy for your fast reply.
I tried to see differences between using SetMaxSize and use of
SetResultSizes, but the difference will not appear.
I use the methods in following manier:
self.DefaultDBSession.Prepare(...);
self.DefaultDBSession.OpenCursor(dynastatement,resultset);
resultset.MaxRows=MyRowCount;
resultSet.SetMaxSize(1,size_of_first);
resultSet.SetMaxSize(2,size_of_second);
resultSet.SetMaxSize(n,size_of_n);
self.DefaultDBSession.SetResultSizes(dynastatement,resultset);
recCount=self.DefaultDBSession.FetchCursor(dynastatement,resultset);
if recCount > 0 then
for eachRow in 1 to resultSet.ActualRows do
resultSet.CurrentRow=eachRow;
resultSet.GetValue(1,class.subclass);
end for;
end if;
self.DefaultDBSession.CloseCursor(dynastatement);
I test this with TextData,IntegerData and scalar types.
I just get more performance with scalar datatypes, but this is normal
without the methods above.
With the TextData and IntegerData Classes i see no difference. Maybe big
BinaryData will
get more performance (Or very big TextData). But I don't test it.
Questions:
1. I calculate the size, by looking in the variables with the debugger
before and set it how it's
calculated. Is there any information (Forte manual or TN) how to
calculate the size (size_of_first...)?
2. Is the position of the methods correct ( SetMaxSize(...) ) between open
and fetch, and before SetResultSizes()?
3. Makes it a better performance to set the resultSize one time (first call
of this method) and calculate it big enough for all
kind of fetches and hold it as long as the dbsession lives (horrible,
but maybe a solution)?
How i am able to get more performance using this features.
Thanks forward for any helpful reply.
At 14:12 21.01.99 +0100, you wrote:
Hi,
I didn't test the SetMaxSize, but I tested and used GetValue.
SetMaxSize should be an optimization for large objects similar
to the load of a text file into a TextData : if you know the
size of what you will load, it should be better to reserve
only that size.
GetValue has 2 signatures and one is given to be better :
- GetValue(name/position) : DataValue : easiest to use but it
instanciates the DataValue
- GetValue(name/position, result) : you instanciate yourself
the result and Forte makes a setvalue on it. It should result
to less instanciations, because you pass to Forte your own reference.
I tested the 2 solutions and couldn't see any real difference on
response time to be honnest, but I used optimized collections too.
A good way to optimize response time is to use the MaxRows parameter
of the FetchCursor (Default is one). It's the size of the buffer
between Forte and the Database for each fetch. You can gain large
factors, but you will pay it on memory of course.
I don't think there is a simple value for it : all this depends on
so much parameters (memory, size of the collection, database, ...).
Hope this helps,
Daniel Nguyen
Freelance Forte Consultant
URL : http://perso.club-internet.fr/dnguyen/
Joseph Mirwald wrote:
Hello Forte-Developers,
are you able to give a short example using this feature?
Are there any benefits which let me have more performance
by using ResultSet.GetValue()?
In the online-help of Forte ( SetMaxSize() ) i read following statement:
Note: The SetMaxSize method is optional. Using it will help performancewhen
the corresponding database type specifies a large object (for example,
BinaryData) and the size of the largest object is known beforehand.How to use this feature, and which value of size is the minimum to get more
performance?
Yepeeeeeeeeeeee... this is the last time this question trashes the mailing
list. I give up if nobody answers or is interested to know something about
using this methods.
Joseph Mirwald

Answer 1

Hi again,
May be to be tested with the SetMaxSize : DBSession.SetResultSize
Here is an extract of the help :
"You use the SetResultSizes method after setting the maximum size of any
columns using the SetMaxSize method or MaxRows attribute (both are in
the DBDataSet class), to set the expected size of any BinaryData objects
to be fetched. The size should be set after invoking the OpenCursor
method and before invoking the first FetchCursor."
Hope this helps,
Daniel Nguyen
Freelance Forte Consultant
URL : http://perso.club-internet.fr/dnguyen/
Joseph Mirwald wrote:
>
Hello Daniel,
i am very happy for your fast reply.
I tried to see differences between using SetMaxSize and use of
SetResultSizes, but the difference will not appear.
I use the methods in following manier:
self.DefaultDBSession.Prepare(...);
self.DefaultDBSession.OpenCursor(dynastatement,resultset);
resultset.MaxRows=MyRowCount;
resultSet.SetMaxSize(1,size_of_first);
resultSet.SetMaxSize(2,size_of_second);
resultSet.SetMaxSize(n,size_of_n);
self.DefaultDBSession.SetResultSizes(dynastatement,resultset);
recCount=self.DefaultDBSession.FetchCursor(dynastatement,resultset);
if recCount > 0 then
for eachRow in 1 to resultSet.ActualRows do
resultSet.CurrentRow=eachRow;
resultSet.GetValue(1,class.subclass);
end for;
end if;
self.DefaultDBSession.CloseCursor(dynastatement);
I test this with TextData,IntegerData and scalar types.
I just get more performance with scalar datatypes, but this is normal
without the methods above.
With the TextData and IntegerData Classes i see no difference. Maybe big
BinaryData will
get more performance (Or very big TextData). But I don't test it.
Questions:
1. I calculate the size, by looking in the variables with the debugger
before and set it how it's
calculated. Is there any information (Forte manual or TN) how to
calculate the size (size_of_first...)?
2. Is the position of the methods correct ( SetMaxSize(...) ) between open
and fetch, and before SetResultSizes()?
3. Makes it a better performance to set the resultSize one time (first call
of this method) and calculate it big enough for all
kind of fetches and hold it as long as the dbsession lives (horrible,
but maybe a solution)?
How i am able to get more performance using this features.
Thanks forward for any helpful reply.
At 14:12 21.01.99 +0100, you wrote:
Hi,
I didn't test the SetMaxSize, but I tested and used GetValue.
SetMaxSize should be an optimization for large objects similar
to the load of a text file into a TextData : if you know the
size of what you will load, it should be better to reserve
only that size.
GetValue has 2 signatures and one is given to be better :
- GetValue(name/position) : DataValue : easiest to use but it
instanciates the DataValue
- GetValue(name/position, result) : you instanciate yourself
the result and Forte makes a setvalue on it. It should result
to less instanciations, because you pass to Forte your own reference.
I tested the 2 solutions and couldn't see any real difference on
response time to be honnest, but I used optimized collections too.
A good way to optimize response time is to use the MaxRows parameter
of the FetchCursor (Default is one). It's the size of the buffer
between Forte and the Database for each fetch. You can gain large
factors, but you will pay it on memory of course.
I don't think there is a simple value for it : all this depends on
so much parameters (memory, size of the collection, database, ...).
Hope this helps,
Daniel Nguyen
Freelance Forte Consultant
URL : http://perso.club-internet.fr/dnguyen/
Joseph Mirwald wrote:
Hello Forte-Developers,
are you able to give a short example using this feature?
Are there any benefits which let me have more performance
by using ResultSet.GetValue()?
In the online-help of Forte ( SetMaxSize() ) i read following statement:
Note: The SetMaxSize method is optional. Using it will help performancewhen
the corresponding database type specifies a large object (for example,
BinaryData) and the size of the largest object is known beforehand.How to use this feature, and which value of size is the minimum to get more
performance?
Yepeeeeeeeeeeee... this is the last time this question trashes the mailing
list. I give up if nobody answers or is interested to know something about
using this methods.
Joseph Mirwald