DataModel.getItemIDs

[Alec Feuerstein <mi...@karoushi.net>]

Hello,

I don't suppose anybody has got getItemIDs or for that matter
getUserIDs working on a
org.apache.mahout.cf.taste.impl.model.jdbc.AbstractJDBCDataModel?

For me, it is swallowing a NoSuchElementException due to a call to
isAfterLast and the ResultSet configuration.  No ids are actually
returned.  I am not totally sure that it is not my setup but I would
be surprised if it was...

There is an easy fix I can submit as a patch if this really is a bug.

-Alec

Re: DataModel.getItemIDs

[Sean Owen <sr...@gmail.com>]

I see. It sounds a bit like a bug in the Derby driver. I don't see why
TYPE_FORWARD_ONLY shouldn't be appropriate there. You should certainly
be able to call hasNext() on such a ResultSet. It is in theory a valid
optimization to tell the driver the ResultSet will only iterate
forward.

On Thu, Oct 7, 2010 at 11:52 PM, Alec Feuerstein <mi...@karoushi.net> wrote:
> Well, I am running Derby on my local box.  I have not tried this in
> particular in our staging environment yet -- which is MySQL.  I think
> it is less a DB issue and more a JDBC thing.  But, the Derby thing
> does make me a bit uncertain.
>
> Basically, by setting ResultSet.TYPE_FORWARD_ONLY, isAfterLast is
> throwing an error which is getting caught and then closing the
> connection.  To aggravate things hasNext -- where the call to
> isAfterLast lives -- is called whenever you are trying to get any
> data...
>
> Setting the result set as ResultSet.TYPE_SCROLL_INSENSITIVE clears
> things up as it allows for scrolling.
>
> -Alec
>
> On Thu, Oct 7, 2010 at 2:13 PM, Sean Owen <sr...@gmail.com> wrote:
>> Hmm, haven't heard of that. Can you provide more details, about the
>> database and such? What you describe doesn't sound like correct
>> behavior. Yes a patch would be great, in describing what the apparent
>> issue is.
>>
>> On Thu, Oct 7, 2010 at 7:55 PM, Alec Feuerstein <mi...@karoushi.net> wrote:
>>> Hello,
>>>
>>> I don't suppose anybody has got getItemIDs or for that matter
>>> getUserIDs working on a
>>> org.apache.mahout.cf.taste.impl.model.jdbc.AbstractJDBCDataModel?
>>>
>>> For me, it is swallowing a NoSuchElementException due to a call to
>>> isAfterLast and the ResultSet configuration.  No ids are actually
>>> returned.  I am not totally sure that it is not my setup but I would
>>> be surprised if it was...
>>>
>>> There is an easy fix I can submit as a patch if this really is a bug.
>>>
>>> -Alec
>>>
>>
>

Re: DataModel.getItemIDs

[Alec Feuerstein <mi...@karoushi.net>]

Well, I am running Derby on my local box.  I have not tried this in
particular in our staging environment yet -- which is MySQL.  I think
it is less a DB issue and more a JDBC thing.  But, the Derby thing
does make me a bit uncertain.

Basically, by setting ResultSet.TYPE_FORWARD_ONLY, isAfterLast is
throwing an error which is getting caught and then closing the
connection.  To aggravate things hasNext -- where the call to
isAfterLast lives -- is called whenever you are trying to get any
data...

Setting the result set as ResultSet.TYPE_SCROLL_INSENSITIVE clears
things up as it allows for scrolling.

-Alec

On Thu, Oct 7, 2010 at 2:13 PM, Sean Owen <sr...@gmail.com> wrote:
> Hmm, haven't heard of that. Can you provide more details, about the
> database and such? What you describe doesn't sound like correct
> behavior. Yes a patch would be great, in describing what the apparent
> issue is.
>
> On Thu, Oct 7, 2010 at 7:55 PM, Alec Feuerstein <mi...@karoushi.net> wrote:
>> Hello,
>>
>> I don't suppose anybody has got getItemIDs or for that matter
>> getUserIDs working on a
>> org.apache.mahout.cf.taste.impl.model.jdbc.AbstractJDBCDataModel?
>>
>> For me, it is swallowing a NoSuchElementException due to a call to
>> isAfterLast and the ResultSet configuration.  No ids are actually
>> returned.  I am not totally sure that it is not my setup but I would
>> be surprised if it was...
>>
>> There is an easy fix I can submit as a patch if this really is a bug.
>>
>> -Alec
>>
>

Re: DataModel.getItemIDs

[Sean Owen <sr...@gmail.com>]

Hmm, haven't heard of that. Can you provide more details, about the
database and such? What you describe doesn't sound like correct
behavior. Yes a patch would be great, in describing what the apparent
issue is.

On Thu, Oct 7, 2010 at 7:55 PM, Alec Feuerstein <mi...@karoushi.net> wrote:
> Hello,
>
> I don't suppose anybody has got getItemIDs or for that matter
> getUserIDs working on a
> org.apache.mahout.cf.taste.impl.model.jdbc.AbstractJDBCDataModel?
>
> For me, it is swallowing a NoSuchElementException due to a call to
> isAfterLast and the ResultSet configuration.  No ids are actually
> returned.  I am not totally sure that it is not my setup but I would
> be surprised if it was...
>
> There is an easy fix I can submit as a patch if this really is a bug.
>
> -Alec
>