[infinispan-dev] new Infinispan Query API - ISPN-194

[Israel Lacerra]

To make a LazyIterator for ISPN-200 (
https://issues.jboss.org/browse/ISPN-200) I was starting a query in each
node and then merging the results (TopDocs) in the requester node...

On Sun, Apr 10, 2011 at 6:10 AM, Emmanuel Bernard <emmanuel at hibernate.org>wrote:

> Why do you need TopDocs? What's the use case?
>
> On 10 avr. 2011, at 03:42, Israel Lacerra wrote:
>
> Guys,
>
> Do you think we can have a getQueryHits() on HSQueryImpl? To do ISPN-200 I
> was using the TopDocs and now, with Infinispan using HSQueryImpl, TopDocs is
> a little more hided....
>
> Anyway, take this just as a "suggestion". I can get the TopDocs in another
> less fashion way :).
>
> cheers
>
> Israel
>
> On Tue, Apr 5, 2011 at 9:23 AM, Emmanuel Bernard <emmanuel at hibernate.org>wrote:
>
>>
>> On 5 avr. 2011, at 13:38, Sanne Grinovero wrote:
>>
>> > 2011/4/5 Emmanuel Bernard <emmanuel at hibernate.org>:
>> >>
>> >> On 5 avr. 2011, at 12:20, Galder Zamarreño wrote:
>> >>
>> >>>
>> >>> On Apr 4, 2011, at 6:23 PM, Sanne Grinovero wrote:
>> >>>
>> >>>> </snip>
>> >>>>
>> >>>> there's one catch:
>> >>>> when searching for a class type, it will only include results from
>> >>>> known subtypes. The targeted type is automatically added to the known
>> >>>> classes, but eventually existing subtypes are not discovered.
>> >>>>
>> >>>> Bringing this issue to an extreme, if the query is not targeting any
>> >>>> type, and no indexed types where added to the grid (even if some
>> exist
>> >>>> already as they might have been inserted by other JVMs or previous
>> >>>> runs), all queries will return no results.
>> >>>> How to solve this?
>> >>>> - class scanning?
>> >>>
>> >>> Nope, too expensive.
>> >>>
>> >>>> - explicitly list indexed entities in Infinispan configuration?
>> >>>
>> >>> No
>> >>>
>> >>>> - a metadata cache maintaining a distributed&stored copy of known
>> types
>> >>>
>> >>> That sounds more appealing. It could be a good middle ground until
>> Search can search for types.
>> >>
>> >> Do you have any specific idea in mind?
>> >>
>> >> To magically find types:
>> >>  - we scan every file system, databases, caches available to the app
>> and look for Lucene metadata => unrealistic
>> >>  - there is some kind of convention on where the indexes are and we do
>> index scanning at startup => scanning are very likely to be slower that
>> class scanning (potential remote access, bigger dataset etc)
>> >>  - we enforce one or a fixed number of Lucene indexes for all data in
>> Infinispan => not sure that's a good idea but this can be explored
>> >>  - we somehow ask the framework using HSearch to fill up classes
>> >>
>> >> other approaches?
>> >
>> > why was class scanning discarded in the first answer? as H. Search can
>> > auto-discover classes by working on top of JPA entity autodiscovery, I
>> > guess that each application node could look into it's own known
>> > classpath.
>> > After all if some type is not visible to him as it was added from
>> > another node from a different app, he won't be able to return
>> > instances of it either.
>> > We could face the opposite problem of building metadata of classes
>> > people doesn't mean to index in this cache.
>>
>> Right. scanning (class or index) will be a bit aggressive and could build
>> unneeded metadata (or even worse, return unexpected classes).
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>
>
>
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