Merge pull request #17244 from vespa-engine/toregge/enable-limited-range-search-with-hash-dictionary

Enable limited range search with hash dictionary (i.e. fallback to filtering).

2 files changed, 13 insertions, 1 deletions

diff --git a/searchlib/src/vespa/searchlib/attribute/postinglistsearchcontext.cpp b/searchlib/src/vespa/searchlib/attribute/postinglistsearchcontext.cpp
index 576506aeea9..b7517094b19 100644
--- a/searchlib/src/vespa/searchlib/attribute/postinglistsearchcontext.cpp
+++ b/searchlib/src/vespa/searchlib/attribute/postinglistsearchcontext.cpp
@@ -57,6 +57,10 @@ void
 PostingListSearchContext::lookupRange(const vespalib::datastore::EntryComparator &low,
                                       const vespalib::datastore::EntryComparator &high)
 {
+    if (!_dictionary.get_has_btree_dictionary()) {
+        _uniqueValues = 2; // Avoid zero and single value optimizations, use filtering
+        return;
+    }
     _lowerDictItr.lower_bound(_frozenDictionary.getRoot(), EnumIndex(), low);
     _upperDictItr = _lowerDictItr;
     if (_upperDictItr.valid() && !high.less(EnumIndex(), _upperDictItr.getKey())) {
diff --git a/searchlib/src/vespa/searchlib/attribute/postinglistsearchcontext.h b/searchlib/src/vespa/searchlib/attribute/postinglistsearchcontext.h
index 3777f3cf4ea..22e9987aa9e 100644
--- a/searchlib/src/vespa/searchlib/attribute/postinglistsearchcontext.h
+++ b/searchlib/src/vespa/searchlib/attribute/postinglistsearchcontext.h
@@ -80,6 +80,9 @@ protected:
     }
 
     virtual bool fallbackToFiltering() const {
+        if (_uniqueValues >= 2 && !_dictionary.get_has_btree_dictionary()) {
+            return true; // force filtering for range search
+        }
         uint32_t numHits = calculateApproxNumHits();
         // numHits > 1000: make sure that posting lists are unit tested.
         return (numHits > 1000) &&
@@ -216,7 +219,7 @@ private:
 
     bool fallbackToFiltering() const override {
         return (this->getRangeLimit() != 0)
-            ? false
+            ? (this->_uniqueValues >= 2 && !this->_dictionary.get_has_btree_dictionary())
             : Parent::fallbackToFiltering();
     }
     unsigned int approximateHits() const override {
@@ -339,6 +342,11 @@ getIterators(bool shouldApplyRangeLimit)
     auto compHigh = _enumStore.make_comparator(capped.upper());
 
     this->lookupRange(compLow, compHigh);
+    if (!this->_dictionary.get_has_btree_dictionary()) {
+        _low = capped.lower();
+        _high = capped.upper();
+        return;
+    }
     if (shouldApplyRangeLimit) {
         this->applyRangeLimit(this->getRangeLimit());
     }