Hello Felix,
note that making something transient is not as simple as just putting
the word next to it, as in case of wicket it will fail not at once but
later;
Also the use of Lists for data sending and/ or partitioning is an
wicket-anti-pattern as it leads to 2 dramatic consequences:
- huge memory required
- slow speed cause by GC
Instead you only should use a own dataProvider;
Note that the 2 queries in there need to be "tuned" for their use,
especially as the size() query will usually be run more than once;
So in your case you should instead cache the query and then construct it
that way:
@Override
public Iterator<? extends T> iterator(int first, int count) {
-> "select id, *....* from A limit FIRST, COUNT";
}
@Override
public int size() {
-> "select count(id) from A";
}
So you only query what is really needed and instead make the part within
the query (e.g.:the querystring) be shared with the DataProvider;
Best
Am 05.04.11 18:48, schrieb felix:
Hi Øyvind,
Nice to hear the integration between both frameworks worked properly.
We implemented a SortableDataProvider but in the method "Iterator
iterator(int first, int count)" we do
proposalsPage = queryRows.subList(first, first+count);
when queryRows is a class variable of type SimpleIdIncrementalFaultList
and not serializable.
and also used in :
public int size() { return (queryRows!=null) ? queryRows.size() : 0;
}
Doing transient List<Proposal> queryRows = null; works but I am
not
sure about further consequences regarding clustering.
How did you handle that SimpleIdIncrementalFaultList cayenne object?
Thanks a lot
Felix
On Tue, 5 Apr 2011 08:24:04 -0700 (PDT), Øyvind Harboe [via Cayenne]
<[email protected]> wrote:
Hi Felix,
I've implemented paged queries using Cayenne and
Wicket.
As I recall you have to implement a "dataprovider" that
will run the query every time the page is rendered. The
objects that are serialized into the page must be small
(per design).
The dataprovider implements sorted, paged queries.
This worked well for a database with 100k's of records
and where I re-ran the query every time the user typed
a new char into a text field to narrow down the search
(including a back-off algorithm supported by the framework).
--
Øyvind Harboe
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