Micheal I have, in the past had to deal with large databases.
even the best enterprise DB has memory problems in this case.
i have had to write Procedures (functions) in the database to parse the
data so it is usable.
That said it is more than just joins, indexes, and where statements, it
is staging the data in a way to make it usable.
one thing that David implemented was Cursors, however not all Databases
that are implemented by ofbiz supports cursors.
that said the place to add these is in the Delegator Classes in my opinion.
Michał Cukierman sent the following on 8/17/2010 9:35 AM:
I know that Ofbiz is limited in some areas, but as far it's the best
place to start. It's better to improve some code than write it all. What
I also think: I have software for free, I can put some effort to improve
it.
So to keep the problem in mind. What is the way of implementing:
1) How to implement Right/Left joins on DynamicViewEntity
2) How to implement my whereString
-> select .... where not in (select ...)
And by the way:
class:CategoryWorker
method:getCategoriesWithNoParent
My change do not affect the system I think. It gets some parameters and
return a query result. So there is not much to break :)
Dnia 2010-08-17, wto o godzinie 10:23 -0600, David E Jones pisze:
I wouldn't say that OFBiz OOTB is a middle of the road compromise, that would
imply consistency in the code which is not the case. The fact is some code is
designed and tested to properly handle millions or even billions of rows in its
target table, and other code can only have a few thousand or perhaps tens of
thousands. There is no general rule or easy way to simplify that down. Things
that are used more by larger organization have tended to be written or improved
over time to handle more data. Things that aren't haven't, it's that simple.
-David
On Aug 17, 2010, at 10:19 AM, Ruth Hoffman wrote:
Hi David:
Thanks for chiming in! I understand and my experience has been exactly as you say:
"Each bit of code and each query needs to be designed with a certain expected data
set size"
What you get with OFBiz out-of-the-box is a middle of the road "compromise".
The really good news is that OFBiz is flexible enough to handle any necessary tweeks.
FYI - I wanted to do more exploration into testing with large data sets and try and
arrive at some guidelines to help determine just how those "tweeks" might work.
I had intended to document the same, but then my database went away and I turned my
attention to other things.
Regards,
Ruth
David E Jones wrote:
One thing to keep in mind is that with database queries and OFBiz there is no
inherent nature of how it handles large data sets. Each bit of code and each
query needs to be designed with a certain expected data set size, and typically
the more data you want to allow for in the data store the more effort and
testing it requires.
In other words, a query and bit of code that doesn't handle a certain large
table means absolutely nothing about how other queries and other code will
handle similarly large tables.
-David
On Aug 17, 2010, at 9:33 AM, Ruth Hoffman wrote:
Hi Micha:
Could I ask how big are your data sets? The reason I ask is that several years
ago, prior to 9.04 I had an out-of-memory problem that was never resolved. The
database tables that I was querying had between 4 - 12 million records. My
database (and OFBiz usage of the same) went away before I couldn't do any
further investigation into the problem.
So, I'm still curious about OFBiz support for really large data sets.
Regards,
Ruth
Michał Cukierman wrote:
Thanks for the quick answer.
I have allocated 2GB of memory, so it's not a case. The problem is that
I work on huge data sets. Version is 10.4 but 9.04 is has the same code.
I have ommited those informations 'couse as you see - it's not relevant
to the topic.
I don't understand your last assumption. Maybe it will someting in my
understanding?
For now I think the best would be to improve the code I have proposed as
it fixes:
1) My issues
2) Coding way of selecting everything to get a couple of categories.
So, thats why I asked about:
1) How to implement Right/Left joins on DynamicViewEntity
(I was able to find out how to creat inner join only)
2) How to implement my whereString
(Haven't found in a code such a use case)
Regards,
Michał
Dnia 2010-08-17, wto o godzinie 07:54 -0700, BJ Freeman pisze:
as far as performance how much memory have you allocated to ofbiz?
what version of ofbiz are you using?
There is a top Category that should be checked for first.
have not been in that part of the code for a while.
Michał Cukierman sent the following on 8/17/2010 7:41 AM:
Hi,
I have a problem with performence (and Out of Memmory Issue) with
catalog management module. There is a section invoked after
Choose Top Category
Collection<GenericValue> allCategories>>>>>>
delegator.findList("ProductCategory", null, null, null, null, false);
for (GenericValue curCat: allCategories) {
Collection<GenericValue> parentCats>>>>>>
curCat.getRelatedCache("CurrentProductCategoryRollup");
if (parentCats.isEmpty())
results.add(curCat);
}
As we see. To get categories without parents we need to fetch for all
categories and for each of them, find a parent.
I do not know Ofbiz api very well for now, so I have implemented:
EntityWhereString where>>>>>>
EntityCondition.makeConditionWhere("PRODUCT_CATEGORY.PRODUCT_CATEGORY_ID
not in" +
" (select PRODUCT_CATEGORY_ROLLUP.PRODUCT_CATEGORY_ID from
PRODUCT_CATEGORY_ROLLUP)");
Set<String> fieldsToSelect = FastSet.newInstance();
fieldsToSelect.add("productCategoryId");
results.addAll(delegator.findList("ProductCategory",
where,
fieldsToSelect, null, null, false));
I simply do invoke a SQL query in the database:
select PRODUCT_CATEGORY.PRODUCT_CATEGORY_ID from PRODUCT_CATEGORY where
PRODUCT_CATEGORY.PRODUCT_CATEGORY_ID not in
(select PRODUCT_CATEGORY_ROLLUP.PRODUCT_CATEGORY_ID from
PRODUCT_CATEGORY_ROLLUP);
Is there a way ( for sure is ) to implement it in a better manner? For
now it works on my system, but after improving the query it could be
passed to a production.
So I got two questions in fact:
1) How to implement Right/Left joins on DynamicViewEntity
2) How to implement my whereString
Thank you in advance,
