Tag hit estimates from attribute search contexts as unknown when applicable.

3 files changed, 51 insertions, 13 deletions

diff --git a/searchlib/src/tests/attribute/imported_search_context/imported_search_context_test.cpp b/searchlib/src/tests/attribute/imported_search_context/imported_search_context_test.cpp
index 79bdd83dc88..93ae9cb13cb 100644
--- a/searchlib/src/tests/attribute/imported_search_context/imported_search_context_test.cpp
+++ b/searchlib/src/tests/attribute/imported_search_context/imported_search_context_test.cpp
@@ -76,15 +76,17 @@ bool is_strict_hit_with_weight(Iterator& iter, TermFieldMatchData& match,
             EXPECT_EQUAL(weight, match.getWeight()));
 }
 
-TEST_F("approximateHits() returns document count of reference attribute when not using fast-search target attribute", Fixture) {
+TEST_F("calc_hit_estimate() returns document count of reference attribute when not using fast-search target attribute", Fixture) {
     add_n_docs_with_undefined_values(*f.target_attr, 10);
     add_n_docs_with_undefined_values(*f.reference_attr, 101);
 
     auto ctx = f.create_context(word_term("foo"));
-    EXPECT_EQUAL(101u, ctx->approximateHits());
+    auto est = ctx->calc_hit_estimate();
+    EXPECT_EQUAL(101u, est.est_hits());
+    EXPECT_TRUE(est.is_unknown());
 }
 
-TEST_F("approximateHits() estimates hits when using fast-search target attribute", Fixture(false, FastSearchConfig::ExplicitlyEnabled))
+TEST_F("calc_hit_estimate() estimates hits when using fast-search target attribute", Fixture(false, FastSearchConfig::ExplicitlyEnabled))
 {
     constexpr uint32_t target_docs = 1000;
     constexpr uint32_t docs = 10000;
@@ -115,16 +117,22 @@ TEST_F("approximateHits() estimates hits when using fast-search target attribute
     f.reference_attr->commit();
     auto ctx = f.create_context(word_term("10"));
     // Exact count: 0 target hits => 0
-    EXPECT_EQUAL(0u, ctx->approximateHits());
+    auto est = ctx->calc_hit_estimate();
+    EXPECT_EQUAL(0u, est.est_hits());
+    EXPECT_FALSE(est.is_unknown());
     TermFieldMatchData match;
     auto iter = f.create_iterator(*ctx, match, false);
     EXPECT_TRUE(iter->matches_any() == Trinary::False);
     ctx = f.create_context(word_term("20"));
     // Exact count: 2 target hits, 2 docs / target doc => 2 * 2 = 4
-    EXPECT_EQUAL(4u, ctx->approximateHits());
+    est = ctx->calc_hit_estimate();
+    EXPECT_EQUAL(4u, est.est_hits());
+    EXPECT_FALSE(est.is_unknown());
     ctx = f.create_context(word_term("30"));
     // Approximation: 110 target hits => 110 * 10001 / 1001 = 1099
-    EXPECT_EQUAL(1099u, ctx->approximateHits());
+    est = ctx->calc_hit_estimate();
+    EXPECT_EQUAL(1099u, est.est_hits());
+    EXPECT_FALSE(est.is_unknown());
 }
 
 TEST_F("attributeName() returns imported attribute name", Fixture) {
diff --git a/searchlib/src/tests/attribute/postinglistattribute/postinglistattribute_test.cpp b/searchlib/src/tests/attribute/postinglistattribute/postinglistattribute_test.cpp
index 3d3ff469546..ed91cefd35c 100644
--- a/searchlib/src/tests/attribute/postinglistattribute/postinglistattribute_test.cpp
+++ b/searchlib/src/tests/attribute/postinglistattribute/postinglistattribute_test.cpp
@@ -498,8 +498,10 @@ PostingListAttributeTest::checkSearch(bool useBitVector, bool need_unpack, bool
     SearchContextPtr sc = getSearch(vec, term, false, attribute::SearchContextParams().useBitVector(useBitVector));
     EXPECT_FALSE( ! sc );
     sc->fetchPostings(queryeval::ExecuteInfo::TRUE);
-    size_t approx = sc->approximateHits();
-    EXPECT_EQ(numHits, approx);
+    auto est = sc->calc_hit_estimate();
+    uint32_t est_hits = est.est_hits();
+    EXPECT_FALSE(est.is_unknown());
+    EXPECT_EQ(numHits, est_hits);
     if (docBegin == 0) {
         // Approximation does not know about the special 0
         // But the iterator does....
@@ -523,7 +525,7 @@ PostingListAttributeTest::checkSearch(bool useBitVector, bool need_unpack, bool
         hits++;
     }
     EXPECT_EQ(numHits, hits);
-    EXPECT_GE(approx, hits);
+    EXPECT_GE(est_hits, hits);
     EXPECT_EQ(docEnd, lastDocId+1);
 }
 
diff --git a/searchlib/src/tests/attribute/searchcontext/searchcontext_test.cpp b/searchlib/src/tests/attribute/searchcontext/searchcontext_test.cpp
index 741a86b0beb..85b13c20f88 100644
--- a/searchlib/src/tests/attribute/searchcontext/searchcontext_test.cpp
+++ b/searchlib/src/tests/attribute/searchcontext/searchcontext_test.cpp
@@ -60,6 +60,7 @@ using largeint_t = AttributeVector::largeint_t;
 using attribute::BasicType;
 using attribute::CollectionType;
 using attribute::Config;
+using attribute::HitEstimate;
 using attribute::SearchContextParams;
 using attribute::test::AttributeBuilder;
 using fef::MatchData;
@@ -87,6 +88,12 @@ public:
 DocSet::DocSet() noexcept = default;
 DocSet::~DocSet() = default;
 
+bool is_flag_attribute(const Config& cfg) {
+    return cfg.fastSearch() &&
+        (cfg.basicType() == BasicType::INT8) &&
+        (cfg.collectionType() == CollectionType::ARRAY);
+}
+
 template <typename V, typename T>
 class PostingList
 {
@@ -104,6 +111,21 @@ public:
     DocSet & getHits() { return _hits; }
     const DocSet & getHits() const { return _hits; }
     uint32_t getHitCount() const { return _hits.size(); }
+    attribute::HitEstimate expected_hit_estimate() const {
+        if (getHitCount() == 0) {
+            return HitEstimate(0);
+        }
+        uint32_t docid_limit = _vec->getStatus().getNumDocs();
+        if (is_flag_attribute(_vec->getConfig())) {
+            return HitEstimate::unknown(docid_limit);
+        } else if (_vec->getConfig().fastSearch()) {
+            return HitEstimate(getHitCount());
+        } else if (_vec->getConfig().collectionType() == CollectionType::SINGLE) {
+            return HitEstimate::unknown(docid_limit);
+        } else {
+            return HitEstimate::unknown(std::max((uint64_t)docid_limit, _vec->getStatus().getNumValues()));
+        }
+    }
 };
 
 template <typename V, typename T>
@@ -166,7 +188,7 @@ private:
     void testSearchIteratorConformance();
     // test search functionality
     template <typename V, typename T>
-    void testFind(const PostingList<V, T> & first);
+    void testFind(const PostingList<V, T> & first, bool verify_hit_estimate);
 
     template <typename V, typename T>
     void testSearch(V & attribute, uint32_t numDocs, const std::vector<T> & values);
@@ -536,10 +558,16 @@ SearchContextTest::checkResultSet(const ResultSet & rs, const DocSet & expected,
 //-----------------------------------------------------------------------------
 template <typename V, typename T>
 void
-SearchContextTest::testFind(const PostingList<V, T> & pl)
+SearchContextTest::testFind(const PostingList<V, T> & pl, bool verify_hit_estimate)
 {
     { // strict search iterator
         SearchContextPtr sc = getSearch(pl.getAttribute(), pl.getValue());
+        if (verify_hit_estimate) {
+            auto act_est = sc->calc_hit_estimate();
+            auto exp_est = pl.expected_hit_estimate();
+            EXPECT_EQUAL(exp_est.est_hits(), act_est.est_hits());
+            EXPECT_EQUAL(exp_est.is_unknown(), act_est.is_unknown());
+        }
         sc->fetchPostings(queryeval::ExecuteInfo::TRUE);
         TermFieldMatchData dummy;
         SearchBasePtr sb = sc->createIterator(&dummy, true);
@@ -571,7 +599,7 @@ SearchContextTest::testSearch(V & attribute, uint32_t numDocs, const std::vector
 
     // test find()
     for (const auto & list : lists) {
-        testFind(list);
+        testFind(list, true);
     }
 }
 
@@ -591,7 +619,7 @@ SearchContextTest::testMultiValueSearchHelper(V & vec, const std::vector<T> & va
     for (const auto & list : lists) {
         //std::cout << "testFind(lists[" << i << "]): value = " << lists[i].getValue()
         //                                            << ", hit count = " << lists[i].getHitCount() << std::endl;
-        testFind(list);
+        testFind(list, false);
     }
 }