lucene-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Martijn van Groningen (Commented) (JIRA)" <>
Subject [jira] [Commented] (LUCENE-3602) Add join query to Lucene
Date Mon, 12 Dec 2011 22:19:31 GMT


Martijn van Groningen commented on LUCENE-3602:

bq. You mean the app sometimes actually uses the fromSearcher.fromQuery's results, directly,
without joining?
Yes. In the case of Solr it is checking the filter cache.

bq. but what worries me is just how slow this non-RAM version will be.
I have been running the JoinQuery on my test data set (10.1 M docs) and it isn't as bad as
I expect it would be. This data set contains 100000 products each product having 100 offers.
The JoinQuery with a *:* query as fromQuery takes about 900 ms and a fromQuery selecting all
products with a specific keyword takes about 350 ms. I think this specific query implementation
is suitable for environments where RAM might be scarce. The RAM version should be the default.

bq. Stepping back a bit... do we know how this impl compares to how ElasticSearch does joins?
And to how Solr does...?
ES only has index time joining, right? Solr basically uses the same mechanism as the JoinQuery
in this patch, but a bit smarter. It tries to cache the from term to to term lookup (see
line 367). I couldn't port this part to joining module since this caching relies heavily on
the SolrIndexSearcher.
> Add join query to Lucene
> ------------------------
>                 Key: LUCENE-3602
>                 URL:
>             Project: Lucene - Java
>          Issue Type: New Feature
>          Components: modules/join
>            Reporter: Martijn van Groningen
>         Attachments: LUCENE-3602.patch, LUCENE-3602.patch
> Solr has (psuedo) join query for a while now. I think this should also be available in

This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators:!default.jspa
For more information on JIRA, see:


To unsubscribe, e-mail:
For additional commands, e-mail:

View raw message