Cleanup code

tsl/src/nodes/decompress_chunk/decompress_chunk.c

@@ -561,27 +561,41 @@ can_sorted_merge_append(PlannerInfo *root, CompressionInfo *info, Chunk *chunk)
 }
 
 /*
- * The logic in make_partition_pruneinfo() contains an assert that checks
- * that relids are unique in a query plan.
+ * Clone the info->chunk_rel ReloptInfo and set the relid to the relid of info->compressed_rel.
+ *
+ * When we access a partially compressed chunk, we create an append path that combines the data
+ * from the compressed part with the uncompressed part. The logic in make_partition_pruneinfo()
+ * contains a check to ensure that relids are unique in an append path.
+ *
+ * To create the path that reads the uncompressed chunk data, the planner calls
+ * decompress_chunk_path_create() again. Therefore, we end up with a second path with the same
+ * RelOptInfo data structure as the real compressed path. So, we need to adjust the relid in one of
+ * these data structures if we want to use both paths in an append path.
+ *
  */
 static void
-adjust_compressed_relid(PlannerInfo *root, CompressionInfo *info, Path *path)
+adjust_compressed_relid_in_path(PlannerInfo *root, CompressionInfo *info, Path *compressed_path,
+								Path *uncompressed_path)
 {
+	/* The compressed path and the uncompressed path share the same RelOptInfo */
+	Assert(compressed_path->parent == uncompressed_path->parent);
+
 	Oid compressed_relid = info->compressed_rel->relid;
 	Oid uncompressed_relid = info->chunk_rel->relid;
 
+	/* Ensure the relid of the uncompressed and the compressed part of the chunk are different */
 	Assert(compressed_relid != uncompressed_relid);
 
-	/* Make sure the planner can find the append rel data structures for the compressed relid */
-	root->append_rel_array[compressed_relid] =
-		root->append_rel_array[uncompressed_relid];
-
-	/* Clone the existing chunk_rel and adjust the relid */
+	/* Clone the chunk_rel RelOptInfo and adjust the relid */
 	RelOptInfo *newrel_opt_info = palloc(sizeof(RelOptInfo));
 	memcpy(newrel_opt_info, info->chunk_rel, sizeof(RelOptInfo));
 	newrel_opt_info->relid = compressed_relid;
 
-	path->parent = newrel_opt_info;
+	/* Assign the new RelOptInfo structure to the compressed_path */
+	compressed_path->parent = newrel_opt_info;
+
+	/* Make sure the planner can find the append rel data structures for the compressed relid */
+	root->append_rel_array[compressed_relid] = root->append_rel_array[uncompressed_relid];
 }
 
 void
@@ -825,9 +839,9 @@ ts_decompress_chunk_generate_paths(PlannerInfo *root, RelOptInfo *chunk_rel, Hyp
 					continue;
 			}
 
-			adjust_compressed_relid(root, info, path);
-
+			adjust_compressed_relid_in_path(root, info, path, uncompressed_path);
 			Assert(path->parent->relid != uncompressed_path->parent->relid);
+
 			path = (Path *) create_append_path_compat(root,
 													  chunk_rel,
 													  list_make2(path, uncompressed_path),
@@ -900,7 +914,8 @@ ts_decompress_chunk_generate_paths(PlannerInfo *root, RelOptInfo *chunk_rel, Hyp
 						continue;
 				}
 
-				adjust_compressed_relid(root, info, path);
+				adjust_compressed_relid_in_path(root, info, path, uncompressed_path);
+				Assert(path->parent->relid != uncompressed_path->parent->relid);
 
 				path = (Path *) create_append_path_compat(root,
 														  chunk_rel,