Query: match_all query (also in query_string: *:*) is very slow, closes elastic#451.

Author: kimchy

modules/elasticsearch/src/main/java/org/elasticsearch/common/lucene/docset/AllDocSet.java

@@ -66,15 +66,15 @@ private AllDocIdSetIterator(int maxDoc) {
             if (++doc < maxDoc) {
                 return doc;
             }
-            return NO_MORE_DOCS;
+            return doc = NO_MORE_DOCS;
         }
 
         @Override public int advance(int target) throws IOException {
             doc = target;
             if (doc < maxDoc) {
                 return doc;
             }
-            return NO_MORE_DOCS;
+            return doc = NO_MORE_DOCS;
         }
     }
 }

modules/elasticsearch/src/main/java/org/elasticsearch/common/lucene/docset/NotDocSet.java

@@ -19,90 +19,26 @@
 
 package org.elasticsearch.common.lucene.docset;
 
-import org.apache.lucene.search.DocIdSetIterator;
-
 import java.io.IOException;
 
 /**
  * @author kimchy (shay.banon)
  */
-public class NotDocSet extends DocSet {
+public class NotDocSet extends GetDocSet {
 
     private final DocSet set;
 
-    private final int max;
-
     public NotDocSet(DocSet set, int max) {
+        super(max);
         this.set = set;
-        this.max = max;
     }
 
     @Override public boolean isCacheable() {
-        return set.isCacheable();
+        // if it is cached, create a new doc set for it so it will be fast for advance in iterator
+        return false;
     }
 
     @Override public boolean get(int doc) throws IOException {
         return !set.get(doc);
     }
-
-    @Override public DocIdSetIterator iterator() throws IOException {
-        return new NotDocIdSetIterator();
-    }
-
-    class NotDocIdSetIterator extends DocIdSetIterator {
-        int lastReturn = -1;
-        private DocIdSetIterator it1 = null;
-        private int innerDocid = -1;
-
-        NotDocIdSetIterator() throws IOException {
-            initialize();
-        }
-
-        private void initialize() throws IOException {
-            it1 = set.iterator();
-
-            try {
-                if ((innerDocid = it1.nextDoc()) == DocIdSetIterator.NO_MORE_DOCS) it1 = null;
-            } catch (IOException e) {
-                e.printStackTrace();
-            }
-        }
-
-        @Override
-        public int docID() {
-            return lastReturn;
-        }
-
-        @Override
-        public int nextDoc() throws IOException {
-            return advance(0);
-        }
-
-        @Override
-        public int advance(int target) throws IOException {
-
-            if (lastReturn == DocIdSetIterator.NO_MORE_DOCS) {
-                return DocIdSetIterator.NO_MORE_DOCS;
-            }
-
-            if (target <= lastReturn) target = lastReturn + 1;
-
-            if (it1 != null && innerDocid < target) {
-                if ((innerDocid = it1.advance(target)) == DocIdSetIterator.NO_MORE_DOCS) {
-                    it1 = null;
-                }
-            }
-
-            while (it1 != null && innerDocid == target) {
-                target++;
-                if (target >= max) {
-                    return (lastReturn = DocIdSetIterator.NO_MORE_DOCS);
-                }
-                if ((innerDocid = it1.advance(target)) == DocIdSetIterator.NO_MORE_DOCS) {
-                    it1 = null;
-                }
-            }
-            return (lastReturn = target);
-        }
-    }
 }