Refactor compatibility macros for PostgreSQL 18 in multi_logical_planner and shard_pruning

src/backend/distributed/planner/multi_logical_planner.c

@@ -65,11 +65,6 @@ typedef struct QualifierWalkerContext
 } QualifierWalkerContext;
 
 
-#if PG_VERSION_NUM >= PG_VERSION_18
-#define get_op_btree_interpretation(opno) get_op_index_interpretation(opno)
-#endif
-
-
 /* Function pointer type definition for apply join rule functions */
 typedef MultiNode *(*RuleApplyFunction) (MultiNode *leftNode, MultiNode *rightNode,
 										 List *partitionColumnList, JoinType joinType,

src/backend/distributed/planner/shard_pruning.c

@@ -181,11 +181,6 @@ typedef struct PruningInstance
 	bool isPartial;
 } PruningInstance;
 
-#if PG_VERSION_NUM >= PG_VERSION_18
-#define get_op_btree_interpretation(opno) get_op_index_interpretation(opno)
-#define ROWCOMPARE_NE COMPARE_NE
-#endif
-
 
 /*
  * Partial instances that need to be finished building. This is used to

src/include/pg_version_compat.h

@@ -29,6 +29,13 @@
 		(j),            /* fdw_restrictinfo*/ \
 		(k)             /* fdw_private     */ \
 		)
+
+/* PG-18 introduced get_op_index_interpretation, old name was get_op_btree_interpretation */
+#define get_op_btree_interpretation(opno) get_op_index_interpretation(opno)
+
+/* PG-18 unified row-compare operator codes under COMPARE_* */
+#define ROWCOMPARE_NE COMPARE_NE
+
 #elif PG_VERSION_NUM >= PG_VERSION_17
 #define create_foreignscan_path_compat(a, b, c, d, e, f, g, h, i, j, k) \
 	create_foreignscan_path( \