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From BJ Freeman <bjf...@free-man.net>
Subject Re: Catalog management performance issue
Date Tue, 17 Aug 2010 16:51:38 GMT
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,
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>
>>>>
>>>>
>>>>
>>
>
>

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