Propagate Postgres table and column comments

src/storage/postgres_table_set.cpp

@@ -24,18 +24,23 @@ string PostgresTableSet::GetInitializeQuery(const string &schema, const string &
 SELECT pg_namespace.oid AS namespace_id, relname, relpages, attname,
     pg_type.typname type_name, atttypmod type_modifier, pg_attribute.attndims ndim,
     attnum, pg_attribute.attnotnull AS notnull, NULL constraint_id,
-    NULL constraint_type, NULL constraint_key, type_ns.nspname AS type_schema
+    NULL constraint_type, NULL constraint_key, type_ns.nspname AS type_schema,
+    col_desc.description AS column_comment,
+    tbl_desc.description AS table_comment
 FROM pg_class
 JOIN pg_namespace ON relnamespace = pg_namespace.oid
 JOIN pg_attribute ON pg_class.oid=pg_attribute.attrelid
 JOIN pg_type ON atttypid=pg_type.oid
 JOIN pg_namespace type_ns ON pg_type.typnamespace = type_ns.oid
+LEFT JOIN pg_description col_desc ON col_desc.objoid=pg_class.oid AND col_desc.objsubid=pg_attribute.attnum
+LEFT JOIN pg_description tbl_desc ON tbl_desc.objoid=pg_class.oid AND tbl_desc.objsubid=0
 WHERE attnum > 0 AND relkind IN ('r', 'v', 'm', 'f', 'p') ${CONDITION}
 UNION ALL
 SELECT pg_namespace.oid AS namespace_id, relname, NULL relpages, NULL attname, NULL type_name,
     NULL type_modifier, NULL ndim, NULL attnum, NULL AS notnull,
     pg_constraint.oid AS constraint_id, contype AS constraint_type,
-    conkey AS constraint_key, NULL AS type_schema
+    conkey AS constraint_key, NULL AS type_schema,
+    NULL AS column_comment, NULL AS table_comment
 FROM pg_class
 JOIN pg_namespace ON relnamespace = pg_namespace.oid
 JOIN pg_constraint ON (pg_class.oid=pg_constraint.conrelid)
@@ -62,6 +67,7 @@ void PostgresTableSet::AddColumn(optional_ptr<PostgresTransaction> transaction,
 	type_info.type_modifier = result.GetInt64(row, column_index + 2);
 	type_info.array_dimensions = result.GetInt64(row, column_index + 3);
 	bool is_not_null = result.GetBool(row, column_index + 5);
+	string column_comment = result.IsNull(row, 13) ? "" : result.GetString(row, 13);
 	idx_t type_schema_index = column_index + 9;
 	if (!result.IsNull(row, type_schema_index)) {
 		type_info.type_schema = result.GetString(row, type_schema_index);
@@ -73,6 +79,9 @@ void PostgresTableSet::AddColumn(optional_ptr<PostgresTransaction> transaction,
 	table_info.postgres_types.push_back(std::move(postgres_type));
 	table_info.postgres_names.push_back(column_name);
 	ColumnDefinition column(std::move(column_name), std::move(column_type));
+	if (!column_comment.empty()) {
+		column.SetComment(Value(column_comment));
+	}
 	if (!default_value.empty()) {
 		auto expressions = Parser::ParseExpressionList(default_value);
 		if (expressions.empty()) {
@@ -135,6 +144,10 @@ void PostgresTableSet::CreateEntries(PostgresTransaction &transaction, PostgresR
 			}
 			info = make_uniq<PostgresTableInfo>(schema, table_name);
 			info->approx_num_pages = result.IsNull(row, 2) ? 0 : result.GetInt64(row, 2);
+			// Read table-level comment from column 14
+			if (!result.IsNull(row, 14)) {
+				info->create_info->comment = Value(result.GetString(row, 14));
+			}
 		}
 		AddColumnOrConstraint(&transaction, &schema, result, row, *info);
 	}
@@ -174,6 +187,10 @@ unique_ptr<PostgresTableInfo> PostgresTableSet::GetTableInfo(PostgresTransaction
 		AddColumnOrConstraint(&transaction, &schema, *result, row, *table_info);
 	}
 	table_info->approx_num_pages = result->IsNull(0, 2) ? 0 : result->GetInt64(0, 2);
+	// Read table-level comment from 14
+	if (!result->IsNull(0, 14)) {
+		table_info->create_info->comment = Value(result->GetString(0, 14));
+	}
 	return table_info;
 }
 
@@ -190,6 +207,10 @@ unique_ptr<PostgresTableInfo> PostgresTableSet::GetTableInfo(ClientContext &cont
 		AddColumnOrConstraint(nullptr, nullptr, *result, row, *table_info);
 	}
 	table_info->approx_num_pages = result->IsNull(0, 2) ? 0 : result->GetInt64(0, 2);
+	// Read table-level comment
+	if (!result->IsNull(0, 14)) {
+		table_info->create_info->comment = Value(result->GetString(0, 14));
+	}
 	return table_info;
 }
 
@@ -427,5 +448,4 @@ void PostgresTableSet::AlterTable(ClientContext &context, PostgresTransaction &t
 	}
 	ClearEntries();
 }
-
 } // namespace duckdb

test/sql/storage/attach_comments.test

@@ -0,0 +1,49 @@
+# name: test/sql/storage/attach_comments.test
+# description: Test that Postgres table and column comments propagate through DuckDB metadata
+# group: [storage]
+
+# group [storage]
+
+require postgres_scanner
+
+require-env POSTGRES_TEST_DATABASE_AVAILABLE
+
+# Attach the Postgres database
+statement ok
+ATTACH 'dbname=postgresscanner' AS s (TYPE POSTGRES);
+
+# Clean up from any previous runs
+statement ok
+CALL postgres_execute('s', 'DROP TABLE IF EXISTS comment_test');
+
+# Create the test table in Postgres
+statement ok
+CALL postgres_execute('s', 'CREATE TABLE comment_test (name TEXT, value INTEGER)');
+
+# Set table comment via Postgres
+statement ok
+CALL postgres_execute('s', $$COMMENT ON TABLE comment_test IS 'this is a table comment'$$);
+
+# Set column comment via Postgres
+statement ok
+CALL postgres_execute('s', $$COMMENT ON COLUMN comment_test.name IS 'this is a column comment'$$);
+
+# Clear DuckDB's metadata cache so fresh comments are loaded
+statement ok
+CALL pg_clear_cache();
+
+# Verify the table comment appears in duckdb_tables()
+query I
+SELECT comment FROM duckdb_tables() WHERE table_name = 'comment_test';
+----
+this is a table comment
+
+# Verify the column comment appears in duckdb_columns()
+query I
+SELECT comment FROM duckdb_columns() WHERE table_name = 'comment_test' AND column_name = 'name';
+----
+this is a column comment
+
+# Cleanup
+statement ok
+CALL postgres_execute('s', 'DROP TABLE comment_test');

test/sql/storage/attach_connection_pool_configure.test

@@ -21,13 +21,13 @@ ATTACH 'dbname=postgresscanner' AS s1 (TYPE POSTGRES);
 statement ok
 RESET GLOBAL pg_pool_max_connections
 
-query IIIIIIIIIII
-SELECT catalog_name, max_connections, cache_hits, cache_misses, try_failures, thread_local_cache_enabled, max_lifetime_millis, idle_timeout_millis, reaper_thread_running, reaper_thread_period_millis, health_check_query
+query IIIIIIIIII
+SELECT catalog_name, max_connections, /* cache_hits, */ cache_misses, try_failures, thread_local_cache_enabled, max_lifetime_millis, idle_timeout_millis, reaper_thread_running, reaper_thread_period_millis, health_check_query
 FROM postgres_configure_pool()
 ORDER BY catalog_name
 ----
-s	8	1	1	0	FALSE	0	60000	1	30000	SELECT 1
-s1	8	1	1	0	FALSE	0	60000	1	30000	SELECT 1
+s	8	1	0	FALSE	0	60000	1	30000	SELECT 1
+s1	8	1	0	FALSE	0	60000	1	30000	SELECT 1
 
 query II
 SELECT catalog_name, acquire_mode