Fix MergeAggregate load meta (#1212)

### What problem does this PR solve?
Should provide empty load meta info for MergeAggregate node

Issue link:#1211

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)
- [x] Test cases

src/executor/physical_planner.cpp

@@ -577,8 +577,7 @@ UniquePtr<PhysicalOperator> PhysicalPlanner::BuildAggregate(const SharedPtr<Logi
                                                   std::move(physical_agg_op),
                                                   logical_aggregate->GetOutputNames(),
                                                   logical_aggregate->GetOutputTypes(),
-                                                  logical_operator->load_metas());
-        // TODO: replace merge op load metas with MakeShared<Vector<LoadMeta>>() ?
+                                                  MakeShared<Vector<LoadMeta>>());
     }
 }
 

test/sql/dql/aggregate/test_agg_load_meta.slt

@@ -0,0 +1,97 @@
+statement ok
+DROP TABLE IF EXISTS test_agg_load_meta;
+
+statement ok
+CREATE TABLE test_agg_load_meta (c1 INTEGER, c2 INTEGER, c3 INTEGER);
+
+query I
+EXPLAIN SELECT COUNT(*) FROM test_agg_load_meta WHERE c2 = 5;
+----
+PROJECT (5)
+ - table index: #4
+ - expressions: [count(star) (#0)]
+-> Merge aggregate (7)
+   - output columns: [COUNT(c1)]
+  -> AGGREGATE (4)
+     - aggregate table index: #3
+     - aggregate: [COUNT(c1 (#1))]
+    -> FILTER (3)
+       - filter: CAST(c2 (#0) AS BigInt) = 5
+       - output columns: [c2, __rowid]
+      -> TABLE SCAN (2)
+         - table name: test_agg_load_meta(default_db.test_agg_load_meta)
+         - table index: #1
+         - output_columns: [c2, __rowid]
+
+query I
+SELECT COUNT(*) FROM test_agg_load_meta WHERE c2 = 5;
+----
+0
+
+statement ok
+COPY test_agg_load_meta FROM '/var/infinity/test_data/basic.csv' WITH ( DELIMITER ',' );
+
+query I
+EXPLAIN SELECT COUNT(*) FROM test_agg_load_meta WHERE c2 = 5;
+----
+PROJECT (5)
+ - table index: #4
+ - expressions: [count(star) (#0)]
+-> AGGREGATE (4)
+   - aggregate table index: #3
+   - aggregate: [COUNT(c1 (#1))]
+  -> FILTER (3)
+     - filter: CAST(c2 (#0) AS BigInt) = 5
+     - output columns: [c2, __rowid]
+    -> TABLE SCAN (2)
+       - table name: test_agg_load_meta(default_db.test_agg_load_meta)
+       - table index: #1
+       - output_columns: [c2, __rowid]
+
+query I
+SELECT COUNT(*) FROM test_agg_load_meta WHERE c2 = 5;
+----
+2
+
+statement ok
+COPY test_agg_load_meta FROM '/var/infinity/test_data/basic.csv' WITH ( DELIMITER ',' );
+
+query I
+EXPLAIN SELECT COUNT(*) FROM test_agg_load_meta WHERE c2 = 5;
+----
+PROJECT (5)
+ - table index: #4
+ - expressions: [count(star) (#0)]
+-> Merge aggregate (7)
+   - output columns: [COUNT(c1)]
+  -> AGGREGATE (4)
+     - aggregate table index: #3
+     - aggregate: [COUNT(c1 (#1))]
+    -> FILTER (3)
+       - filter: CAST(c2 (#0) AS BigInt) = 5
+       - output columns: [c2, __rowid]
+      -> TABLE SCAN (2)
+         - table name: test_agg_load_meta(default_db.test_agg_load_meta)
+         - table index: #1
+         - output_columns: [c2, __rowid]
+
+query I
+SELECT COUNT(*) FROM test_agg_load_meta WHERE c2 = 5;
+----
+4
+
+statement ok
+DELETE FROM test_agg_load_meta WHERE c2 = 5;
+
+query I
+SELECT COUNT(*) FROM test_agg_load_meta WHERE c2 = 5;
+----
+0
+
+query I
+SELECT COUNT(*) FROM test_agg_load_meta;
+----
+6
+
+statement ok
+DROP TABLE test_agg_load_meta;