Doug
Ype Kingma wrote:
Dear developers,
public TopDocs search(Query query, Filter filter, int nDocs)
contains an
else break; which discards previous interim results.
Since I expect to need in the order of 100 best results from
20 databases on a regular basis I don't really like this.
This is the current code:
for (int i = 0; i < searchables.length; i++) { // search each searcher
TopDocs docs = searchables[i].search(query, filter, nDocs);
totalHits += docs.totalHits; // update totalHits
ScoreDoc[] scoreDocs = docs.scoreDocs;
for (int j = 0; j < scoreDocs.length; j++) { // merge scoreDocs into hq
ScoreDoc scoreDoc = scoreDocs[j];
if (scoreDoc.score >= minScore) {
scoreDoc.doc += starts[i]; // convert doc
hq.put(scoreDoc); // update hit queue
if (hq.size() > nDocs) { // if hit queue overfull
hq.pop(); // remove lowest in hit queue
minScore = ((ScoreDoc)hq.top()).score; // reset minScore
}
} else
break; // no more scores > minScore
}
}
Attached is an untested patch for this. It works by implementing
a MultiCollector that has the state to collect results from
the subsearchers without discarding interim results.
The patch is a dif -c against current CVS.
I'd like to add some test cases, but before I do that
I'd prefer to have comments.
I checked the testcases for MultiSearcher, but they don't
seem to exercise the code in the patch.
The existing test-unit build runs fine with the patch.
Regards,
Ype
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Index: jakarta-lucene/src/java/org/apache/lucene/search/MultiSearcher.java
===================================================================
RCS file: /home/cvspublic/jakarta-lucene/src/java/org/apache/lucene/search/MultiSearcher.java,v
retrieving revision 1.10
diff -c -r1.10 MultiSearcher.java
*** jakarta-lucene/src/java/org/apache/lucene/search/MultiSearcher.java 29 Jan 2003 17:18:54 -0000 1.10
--- jakarta-lucene/src/java/org/apache/lucene/search/MultiSearcher.java 3 Feb 2003 22:43:35 -0000
***************
*** 141,175 ****
return maxDoc;
}
public TopDocs search(Query query, Filter filter, int nDocs)
throws IOException {
! HitQueue hq = new HitQueue(nDocs);
! float minScore = 0.0f;
! int totalHits = 0;
! ! for (int i = 0; i < searchables.length; i++) { // search each searcher
! TopDocs docs = searchables[i].search(query, filter, nDocs);
! totalHits += docs.totalHits; // update totalHits
! ScoreDoc[] scoreDocs = docs.scoreDocs;
! for (int j = 0; j < scoreDocs.length; j++) { // merge scoreDocs into hq
! ScoreDoc scoreDoc = scoreDocs[j];
! if (scoreDoc.score >= minScore) {
! scoreDoc.doc += starts[i]; // convert doc
! hq.put(scoreDoc); // update hit queue
! if (hq.size() > nDocs) { // if hit queue overfull
! hq.pop(); // remove lowest in hit queue
! minScore = ((ScoreDoc)hq.top()).score; // reset minScore
}
! } else
! break; // no more scores > minScore
}
}
ScoreDoc[] scoreDocs = new ScoreDoc[hq.size()];
! for (int i = hq.size()-1; i >= 0; i--) // put docs in array
scoreDocs[i] = (ScoreDoc)hq.pop();
! return new TopDocs(totalHits, scoreDocs);
}
--- 141,198 ----
return maxDoc;
}
+ public TopDocs search(Query query, Filter filter, int nDocs)
throws IOException {
! ! class MultiCollector extends HitCollector {
! HitQueue hq;
! int nDocs = 0;
! int totalHits = 0;
! int start = 0;
! float minScore = 0.0f;
! ScoreDoc scoreDoc = null; /* reuse last one discarded from hitqueue hq */
! ! public MultiCollector(int nd) {
! nDocs = nd;
! hq = new HitQueue(nd);
! }
! ! public void collect(int doc, float score) {
! totalHits++;
! System.out.println(getClass() + " hits: " + totalHits + ", start: " + start
! + ", docNr: " + doc + ", score: " + score);
! if (score >= minScore) {
! if (scoreDoc == null) {
! scoreDoc = new ScoreDoc(doc + start, score);
! } else {
! scoreDoc.doc = doc + start;
! scoreDoc.score = score;
! }
! hq.put(scoreDoc);
! if (hq.size() > nDocs) {
! scoreDoc = (ScoreDoc) hq.pop();
! minScore = ((ScoreDoc)hq.top()).score;
! } else {
! scoreDoc = null;
}
! }
}
}
+ MultiCollector mc = new MultiCollector(nDocs);
+ + for (int i = 0; i < searchables.length; i++) {
+ mc.start = starts[i];
+ searchables[i].search(query, filter, mc);
+ }
+ + HitQueue hq = mc.hq;
ScoreDoc[] scoreDocs = new ScoreDoc[hq.size()];
! for (int i = hq.size()-1; i >= 0; i--)
scoreDocs[i] = (ScoreDoc)hq.pop();
! return new TopDocs(mc.totalHits, scoreDocs);
}
***************
*** 201,207 ****
}
}
! public Query rewrite(Query original) throws IOException {
Query[] queries = new Query[searchables.length];
for (int i = 0; i < searchables.length; i++) {
--- 224,230 ----
}
}
! public Query rewrite(Query original) throws IOException {
Query[] queries = new Query[searchables.length];
for (int i = 0; i < searchables.length; i++) {
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