Mailing-List: contact java-dev-help@lucene.apache.org; run by ezmlm
Precedence: bulk
Reply-To: java-dev@lucene.apache.org
Message-ID: <202607808.1239693315020.JavaMail.jira@brutus>
Date: Tue, 14 Apr 2009 00:15:15 -0700 (PDT)
From: "Shai Erera (JIRA)" <jira@apache.org>
To: java-dev@lucene.apache.org
Subject: [jira] Commented: (LUCENE-1593) Optimizations to
 TopScoreDocCollector and TopFieldCollector
In-Reply-To: <1791214986.1239268813267.JavaMail.jira@brutus>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit


    [ https://issues.apache.org/jira/browse/LUCENE-1593?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12698674#action_12698674 ] 

Shai Erera commented on LUCENE-1593:
------------------------------------

I noticed that IndexSearcher has a ctor which allows to define whether documents are intended to be collected in-order of out-of-order. I assume we have to remove that ctor and also sortSubReaders? If we change TSDC and TFC to always assume docs come in order, this cannot be configurable.

I thought these were introduced as part of LUCENE-1483 for performance reasons. Are we sure that removing these, just for the sake of what looks like minor optimizations to TSDC and TFC (not breaking a tie on doc Id) is worth it?

> Optimizations to TopScoreDocCollector and TopFieldCollector
> -----------------------------------------------------------
>
>                 Key: LUCENE-1593
>                 URL: https://issues.apache.org/jira/browse/LUCENE-1593
>             Project: Lucene - Java
>          Issue Type: Improvement
>          Components: Search
>            Reporter: Shai Erera
>             Fix For: 2.9
>
>
> This is a spin-off of LUCENE-1575 and proposes to optimize TSDC and TFC code to remove unnecessary checks. The plan is:
> # Ensure that IndexSearcher returns segements in increasing doc Id order, instead of numDocs().
> # Change TSDC and TFC's code to not use the doc id as a tie breaker. New docs will always have larger ids and therefore cannot compete.
> # Pre-populate HitQueue with sentinel values in TSDC (score = Float.NEG_INF) and remove the check if reusableSD == null.
> # Also move to use "changing top" and then call adjustTop(), in case we update the queue.
> # some methods in Sort explicitly add SortField.FIELD_DOC as a "tie breaker" for the last SortField. But, doing so should not be necessary (since we already break ties by docID), and is in fact less efficient (once the above optimization is in).
> # Investigate PQ - can we deprecate insert() and have only insertWithOverflow()? Add a addDummyObjects method which will populate the queue without "arranging" it, just store the objects in the array (this can be used to pre-populate sentinel values)?
> I will post a patch as well as some perf measurements as soon as I have them.

-- 
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.


---------------------------------------------------------------------
To unsubscribe, e-mail: java-dev-unsubscribe@lucene.apache.org
For additional commands, e-mail: java-dev-help@lucene.apache.org