CBL-6576: Implement Partial Index LiteCore API

Added field "where" to C4IndexOptions and implemented it.
couchbase · Jan 24, 2025 · bc982fd · bc982fd
1 parent 8015487
commit bc982fd
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Showing 3 changed files with 45 additions and 2 deletions.
diff --git a/C/include/c4IndexTypes.h b/C/include/c4IndexTypes.h
@@ -127,6 +127,9 @@ typedef struct C4IndexOptions {
     /** Options for vector indexes. */
     C4VectorIndexOptions vector;
 #endif
+
+    /** The where clause for partial indexes. Currently only Value and FullText indexes support partial index */
+    const char* C4NULLABLE where;
 } C4IndexOptions;
 
 /** @} */

diff --git a/C/tests/c4QueryTest.cc b/C/tests/c4QueryTest.cc
@@ -14,6 +14,7 @@
 #include "c4Collection.h"
 #include "c4Observer.h"
 #include "StringUtil.hh"
+#include "SQLiteDataFile.hh"
 #include <thread>
 using namespace std;
 
@@ -285,6 +286,37 @@ N_WAY_TEST_CASE_METHOD(C4QueryTest, "C4Query expression index", "[Query][C]") {
     CHECK(run() == (vector<string>{"0000015", "0000099"}));
 }
 
+N_WAY_TEST_CASE_METHOD(C4QueryTest, "C4Query partial value index", "[Query][C]") {
+    C4Error err;
+    auto    defaultColl = getCollection(db, kC4DefaultCollectionSpec);
+    for ( int withIndex = 0; withIndex < 2; ++withIndex ) {
+        if ( withIndex ) {
+            C4IndexOptions options{};
+            options.where = "gender = 'female'";
+            REQUIRE(c4coll_createIndex(defaultColl, C4STR("length"), c4str("length(name.first)"), kC4N1QLQuery,
+                                       kC4ValueIndex, &options, WITH_ERROR(&err)));
+        }
+        c4query_release(query);
+        const char* queryStr = "SELECT META().id FROM _ WHERE length(name.first) = 9 AND gender = 'female'";
+        query                = c4query_new2(db, kC4N1QLQuery, c4str(queryStr), nullptr, ERROR_INFO(err));
+        REQUIRE(query);
+        checkExplanation(withIndex);
+        CHECK(run() == (vector<string>{"0000099"}));
+
+        if ( withIndex ) {
+            c4query_release(query);
+            // Logically equivalent query, changing gender = 'female' to gender != 'male'.
+            // Because the condition is not exact as the condition in partial index, it would not use
+            // the index.
+            const char* queryStr2 = "SELECT META().id FROM _ WHERE length(name.first) = 9 AND gender != 'male'";
+            query                 = c4query_new2(db, kC4N1QLQuery, c4str(queryStr2), nullptr, ERROR_INFO(err));
+            REQUIRE(query);
+            checkExplanation(!withIndex);
+            CHECK(run() == (vector<string>{"0000099"}));
+        }
+    }
+}
+
 static bool lookForIndex(C4Database* db, slice name) {
     bool found       = false;
     auto defaultColl = C4QueryTest::getCollection(db, kC4DefaultCollectionSpec);

diff --git a/LiteCore/Database/CollectionImpl.hh b/LiteCore/Database/CollectionImpl.hh
@@ -480,8 +480,16 @@ namespace litecore {
                     error::_throw(error::InvalidParameter, "Invalid index type");
                     break;
             }
-            keyStore().createIndex(indexName, indexSpec, (QueryLanguage)indexLanguage, (IndexSpec::Type)indexType,
-                                   options);
+            if ( indexOptions ) {
+                constexpr const char* indexTypeNames[] = {"Value", "FullText", "Array", "Predictive", "Vector"};
+                if ( indexOptions->where && !IndexSpec::canPartialIndex((IndexSpec::Type)indexType) )
+                    error::_throw(error::InvalidParameter, "%s index does support partial index.",
+                                  indexTypeNames[indexType]);
+            }
+
+            keyStore().createIndex({indexName.asString(), (IndexSpec::Type)indexType, indexSpec,
+                                    slice{indexOptions ? indexOptions->where : nullptr}, (QueryLanguage)indexLanguage,
+                                    options});
         }
 
         Retained<C4Index> getIndex(slice name) override { return C4Index::getIndex(this, name); }