Correct fallback if not positive quals.

Author: akorotkov

jsonb_gin_ops.c

@@ -657,13 +657,20 @@ gin_extract_jsonb_query_bloom_value(PG_FUNCTION_ARGS)
 		case JsQueryMatchStrategyNumber:
 			jq = PG_GETARG_JSQUERY(0);
 			root = extractJsQuery(jq, make_bloom_entry_handler, (Pointer)&e);
-
-			*nentries = e.count;
-			entries = e.entries;
-			*pmatch = e.partial_match;
-			*extra_data = e.extra_data;
-			for (i = 0; i < e.count; i++)
-				((KeyExtra *)e.extra_data[i])->root = root;
+			if (root)
+			{
+				*nentries = e.count;
+				entries = e.entries;
+				*pmatch = e.partial_match;
+				*extra_data = e.extra_data;
+				for (i = 0; i < e.count; i++)
+					((KeyExtra *)e.extra_data[i])->root = root;
+			}
+			else
+			{
+				entries = NULL;
+				*nentries = 0;
+			}
 			break;
 
 		default:
@@ -1071,13 +1078,20 @@ gin_extract_jsonb_query_hash_value(PG_FUNCTION_ARGS)
 		case JsQueryMatchStrategyNumber:
 			jq = PG_GETARG_JSQUERY(0);
 			root = extractJsQuery(jq, make_hash_entry_handler, (Pointer)&e);
-
-			*nentries = e.count;
-			entries = e.entries;
-			*pmatch = e.partial_match;
-			*extra_data = e.extra_data;
-			for (i = 0; i < e.count; i++)
-				((KeyExtra *)e.extra_data[i])->root = root;
+			if (root)
+			{
+				*nentries = e.count;
+				entries = e.entries;
+				*pmatch = e.partial_match;
+				*extra_data = e.extra_data;
+				for (i = 0; i < e.count; i++)
+					((KeyExtra *)e.extra_data[i])->root = root;
+			}
+			else
+			{
+				entries = NULL;
+				*nentries = 0;
+			}
 			break;
 
 		default:

jsquery_extract.c

@@ -568,6 +568,42 @@ makeEntries(ExtractedNode *node, MakeEntryHandler handler, Pointer extra)
 	}
 }
 
+static bool
+queryHasPositive(ExtractedNode *node)
+{
+	int i;
+	bool result;
+	switch(node->type)
+	{
+		case eAnd:
+			result = false;
+			for (i = 0; i < node->args.count; i++)
+			{
+				if (queryHasPositive(node->args.items[i]))
+				{
+					result = true;
+					break;
+				}
+			}
+			return result;
+		case eOr:
+			result = true;
+			for (i = 0; i < node->args.count; i++)
+			{
+				if (!queryHasPositive(node->args.items[i]))
+				{
+					result = false;
+					break;
+				}
+			}
+			return result;
+		case eNot:
+			return !queryHasPositive(node->args.items[0]);
+		case eScalar:
+			return true;
+	}
+}
+
 ExtractedNode *
 extractJsQuery(JsQuery *jq, MakeEntryHandler handler, Pointer extra)
 {
@@ -580,6 +616,8 @@ extractJsQuery(JsQuery *jq, MakeEntryHandler handler, Pointer extra)
 		simplifyRecursive(root);
 		root = makeEntries(root, handler, extra);
 	}
+	if (root && !queryHasPositive(root))
+		root = NULL;
 	return root;
 }