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From "Ning Li" <ning.li...@gmail.com>
Subject Re: Efficiently expunging deletions of recently added documents
Date Tue, 05 Dec 2006 18:01:27 GMT
An old issue (http://issues.apache.org/jira/browse/LUCENE-325 new
method expungeDeleted() added to IndexWriter) requested a similar
functionality as described in the latter half of your email.

The patch for that issue breaks the invariants of the new merge
policy. An algorithm similar to that of addIndexesNoOptimize()
(http://issues.apache.org/jira/browse/LUCENE-528 Optimization for
IndexWriter.addIndexes()) would solve the problem.

Ning

On 12/5/06, Ning Li <ning.li.li@gmail.com> wrote:
> > I'd like to open up the API to mergeSegments() in IndexWriter and am
> > wondering if there are potential problems with this.
>
> I'm worried that opening up mergeSegments() could easily break the
> invariants currently guaranteed by the new merge
> policy(http://issues.apache.org/jira/browse/LUCENE-672).
>
> The two invariants say that if M does not change and segment doc count
> is not reaching maxMergeDocs:
> B for maxBufferedDocs, f(n) defined as ceil(log_M(ceil(n/B)))
> 1: If i (left*) and i+1 (right*) are two consecutive segments of doc
> counts x and y, then f(x) >= f(y).
> 2: The number of committed segments on the same level (f(n)) <= M.
>
> Ning
>

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