My point is that oracle does not support scrollable cursors at the DB server. When we use a scrollable cursor with ORACLE it's the JDBC code that makes it look like we are fetching only 100 of records out of a large no of possible records. The query that executes against the DB actually fetches the entire set of records and not 100. It's nothing to do with the GenericDAO just the behaviour of ORACLE. So if the DB is ORACLE even if we use a EntityListIterator it doesn't do proper pagination
BJ Freeman wrote: > > just as a side note > http://docs.ofbiz.org/display/~jacopoc/OFBiz+and+Oracle > > if you notice in the framework/entity/config/entityengine.xml for oracle > <datasource name="localoracle" > helper-class="org.ofbiz.entity.datasource.GenericHelperDAO" > and the underlying GenericDAO.java > is where you would address these concerns. > > > > phantom.coding sent the following on 8/28/2008 6:02 AM: >> Agree that EntityListIterator keeps database cursor open and uses that to >> retrive the results. Which means that we should use a scrollable cursor >> (correct me if I'm wrong!!). But when working with ORACLE this doesn't >> work. >> Oracle does not support scrollable cursors. It's the JDBC layer that >> simulates the scrollable cursor and not the DB server. So even if we >> fetch >> results 100 by 100 at JDBC level the full result set is fetched. >> >> Pls correct me if i'm wrong >> >> >> >> >> David E. Jones-2 wrote: >>> >>> This is incorrect. The EntityListIterator uses a database cursor and >>> keeps the connection open to the database. Depending on what the >>> database and JDBC driver support and how things are configured, it >>> will typically pull over 100 records at a time over the network as it >>> scrolls through or jumps around the result set. >>> >>> As to your specific performance problems, with that information I >>> have no idea what the problem might be. It depends on how you have >>> deployed OFBiz, how the database and JDBC driver are setup, and if >>> the custom or OOTB OFBiz code is written properly to use the >>> EntityListIterator. >>> >>> -David >>> >>> >>> On Jan 31, 2007, at 4:53 PM, Jonathon -- Improov wrote: >>> >>>> I could be wrong, but it seems OFBiz pulls down all records (1000s >>>> possibly) before putting all those records through that function. >>>> Yeah, I know, the partial list is gleaned off of the resultset and >>>> so it seems that we're not exactly swallowing all records first. >>>> >>>> But isn't it more database-independent (or less?) to use SQL LIMIT? >>>> >>>> I'm seeing long load times for LookUpProduct service when listing >>>> for pagination a mere 1000 records. Perhaps it'll be much much >>>> faster using SQL LIMIT? I know for a fact that using SQL LIMIT is >>>> faster than scrolling through a resultset, know that based on my >>>> own apps (currently having entity framework that provides for SQL >>>> LIMIT). >>>> >>>> Jonathon >>>> >>>> David E. Jones wrote: >>>>> Could you explain how that would be different and better than >>>>> using the EntityListIterator.getPartialList method? >>>>> -David >>>>> On Jan 31, 2007, at 11:21 AM, Leon Torres wrote: >>>>>> Hi David, >>>>>> >>>>>> Sorry, maybe I should have expressed this in the form of two >>>>>> questions. >>>>>> >>>>>> Is there a way to do a query with OFFSET and LIMIT using >>>>>> EntityCondition? >>>>>> >>>>>> If not, then is there a way to do these offset and limit >>>>>> operations with findEntityListIteratorByCondition? >>>>>> >>>>>> - Leon >>>>>> >>>>>> >>>>>> >>>>>> David E. Jones wrote: >>>>>>> What's wrong with the stuff that's been there for years on the >>>>>>> EntityListIterator? >>>>>>> -David >>>>>>> On Jan 30, 2007, at 4:52 PM, Leon Torres wrote: >>>>>>>> Hi folks, >>>>>>>> >>>>>>>> I think we really need to be able to specify the size of the >>>>>>>> list we want and the index to start at for the >>>>>>>> GenericDelegator.findByAnd and findByCondition methods. >>>>>>>> >>>>>>>> The idea is to support pagination in the form widgets and >>>>>>>> similar systems for lists of data that cannot be supported by >>>>>>>> <view-entity>. For example, if the inventory QOH and ATP are >>>>>>>> required for a form-widget list, we need to call the >>>>>>>> getInventoryAvailableByFacility service and add the results to >>>>>>>> each list row. Another example would be a union of various >>>>>>>> entities together, some of which need heuristics to select the >>>>>>>> data. >>>>>>>> >>>>>>>> It should be relatively simple: Create a method that wraps a >>>>>>>> call to findListIteratorByCondition, then grab the desired >>>>>>>> range of results. It should also return the size of the table. >>>>>>>> >>>>>>>> Then, as an example, we can call these methods with our >>>>>>>> viewSize and viewIndex parameters, build our complex list of >>>>>>>> data based on the results, and use the form-widget's override- >>>>>>>> list-size to make pagination work with it. >>>>>>>> >>>>>>>> Thoughts? >>>>>>>> >>>>>>>> - Leon >>> >>> >>> >> > > > -- View this message in context: http://www.nabble.com/Idea%3A--be-able-to-specify-size-and-index-of-entity-lists-tp8720621p19214628.html Sent from the OFBiz - Dev mailing list archive at Nabble.com.
