feat(query): add system.zero table && support empty result for empty stage (#18453)

sundy-li · web-flow · commit e570d289c233 · 2025-08-05T10:16:57.000+08:00
* feat(query): add zero table

* feat(query): add zero table

* feat(query): add zero table

* feat(query): add zero table

* feat(query): add zero table

* feat(query): add zero table
diff --git a/src/common/storage/src/stage.rs b/src/common/storage/src/stage.rs
@@ -201,19 +201,10 @@ impl StageFilesInfo {
     }
 
     #[async_backtrace::framed]
-    pub async fn first_file(&self, operator: &Operator) -> Result<StageFileInfo> {
+    pub async fn first_file(&self, operator: &Operator) -> Result<Option<StageFileInfo>> {
         // We only fetch first file.
         let mut files = self.list(operator, 1, Some(1)).await?;
-        files
-            .pop()
-            .ok_or_else(|| ErrorCode::BadArguments("no file found"))
-    }
-
-    pub fn blocking_first_file(&self, operator: &Operator) -> Result<StageFileInfo> {
-        let mut files = self.blocking_list(operator, Some(1))?;
-        files
-            .pop()
-            .ok_or_else(|| ErrorCode::BadArguments("no file found"))
+        Ok(files.pop())
     }
 
     pub fn blocking_list(
diff --git a/src/query/catalog/src/table_context.rs b/src/query/catalog/src/table_context.rs
@@ -275,6 +275,13 @@ pub trait TableContext: Send + Sync {
     async fn get_table(&self, catalog: &str, database: &str, table: &str)
         -> Result<Arc<dyn Table>>;
 
+    async fn get_zero_table(&self) -> Result<Arc<dyn Table>> {
+        let catalog = self.get_catalog("default").await?;
+        catalog
+            .get_table(&self.get_tenant(), "system", "zero")
+            .await
+    }
+
     fn evict_table_from_cache(&self, catalog: &str, database: &str, table: &str) -> Result<()>;
 
     async fn get_table_with_batch(
diff --git a/src/query/service/src/databases/system/system_database.rs b/src/query/service/src/databases/system/system_database.rs
@@ -70,6 +70,7 @@ use databend_common_storages_system::UsersTable;
 use databend_common_storages_system::ViewsTableWithHistory;
 use databend_common_storages_system::ViewsTableWithoutHistory;
 use databend_common_storages_system::VirtualColumnsTable;
+use databend_common_storages_system::ZeroTable;
 use databend_common_version::DATABEND_CARGO_CFG_TARGET_FEATURE;
 use databend_common_version::DATABEND_COMMIT_AUTHORS;
 use databend_common_version::DATABEND_CREDITS_LICENSES;
@@ -105,6 +106,7 @@ impl SystemDatabase {
     ) -> Self {
         let mut table_list = vec![
             OneTable::create(sys_db_meta.next_table_id()),
+            ZeroTable::create(sys_db_meta.next_table_id()),
             FunctionsTable::create(sys_db_meta.next_table_id()),
             ContributorsTable::create(sys_db_meta.next_table_id(), DATABEND_COMMIT_AUTHORS),
             CreditsTable::create(
diff --git a/src/query/service/src/sessions/query_ctx.rs b/src/query/service/src/sessions/query_ctx.rs
@@ -1771,6 +1771,7 @@ impl TableContext for QueryContext {
                         read_options = read_options.with_do_prewhere(false);
                     }
                     ParquetTable::create(
+                        self,
                         stage_info.clone(),
                         files_info,
                         read_options,
@@ -1823,7 +1824,7 @@ impl TableContext for QueryContext {
                     stage_root,
                     is_variant,
                 };
-                OrcTable::try_create(info).await
+                OrcTable::try_create(self, info).await
             }
             FileFormatParams::NdJson(..) | FileFormatParams::Avro(..) => {
                 let schema = Arc::new(TableSchema::new(vec![TableField::new(
diff --git a/src/query/service/src/table_functions/infer_schema/parquet.rs b/src/query/service/src/table_functions/infer_schema/parquet.rs
@@ -127,8 +127,9 @@ impl AsyncSource for ParquetInferSchemaSource {
             Some(f) => self.ctx.get_file_format(f).await?,
             None => stage_info.file_format_params.clone(),
         };
-        let schema = match file_format_params.get_type() {
-            StageFileFormatType::Parquet => {
+        let schema = match (first_file.as_ref(), file_format_params.get_type()) {
+            (None, _) => return Ok(None),
+            (Some(first_file), StageFileFormatType::Parquet) => {
                 let arrow_schema = read_parquet_schema_async_rs(
                     &operator,
                     &first_file.path,
diff --git a/src/query/service/src/table_functions/inspect_parquet/inspect_parquet_table.rs b/src/query/service/src/table_functions/inspect_parquet/inspect_parquet_table.rs
@@ -237,9 +237,12 @@ impl AsyncSource for InspectParquetSource {
         };
 
         let first_file = file_info.first_file(&operator).await?;
-
+        let Some(first_file) = first_file else {
+            return Ok(None);
+        };
         let parquet_schema =
             read_metadata_async(&first_file.path, &operator, Some(first_file.size)).await?;
+
         let created = match parquet_schema.file_metadata().created_by() {
             Some(user) => user.to_owned(),
             None => String::from("NULL"),
diff --git a/src/query/service/tests/it/storages/testdata/columns_table.txt b/src/query/service/tests/it/storages/testdata/columns_table.txt
@@ -156,6 +156,7 @@ DB.Table: 'system'.'columns', Table: columns-table_id:1, ver:0, Engine: SystemCo
 | 'dropped_on'                      | 'system'             | 'views'                  | 'Nullable(Timestamp)' | 'TIMESTAMP'         | ''       | ''       | 'YES'    | ''       | NULL     | NULL      | NULL      |
 | 'dropped_on'                      | 'system'             | 'views_with_history'     | 'Nullable(Timestamp)' | 'TIMESTAMP'         | ''       | ''       | 'YES'    | ''       | NULL     | NULL      | NULL      |
 | 'dummy'                           | 'system'             | 'one'                    | 'UInt8'               | 'TINYINT UNSIGNED'  | ''       | ''       | 'NO'     | ''       | NULL     | NULL      | NULL      |
+| 'dummy'                           | 'system'             | 'zero'                   | 'UInt8'               | 'TINYINT UNSIGNED'  | ''       | ''       | 'NO'     | ''       | NULL     | NULL      | NULL      |
 | 'enabled'                         | 'system'             | 'notifications'          | 'Boolean'             | 'BOOLEAN'           | ''       | ''       | 'NO'     | ''       | NULL     | NULL      | NULL      |
 | 'end_time'                        | 'system'             | 'clustering_history'     | 'Timestamp'           | 'TIMESTAMP'         | ''       | ''       | 'NO'     | ''       | NULL     | NULL      | NULL      |
 | 'engine'                          | 'information_schema' | 'tables'                 | 'String'              | 'VARCHAR'           | ''       | ''       | 'NO'     | ''       | NULL     | NULL      | NULL      |
diff --git a/src/query/storages/orc/src/table.rs b/src/query/storages/orc/src/table.rs
@@ -71,7 +71,10 @@ impl OrcTable {
     }
 
     #[async_backtrace::framed]
-    pub async fn try_create(mut stage_table_info: StageTableInfo) -> Result<Arc<dyn Table>> {
+    pub async fn try_create(
+        ctx: &dyn TableContext,
+        mut stage_table_info: StageTableInfo,
+    ) -> Result<Arc<dyn Table>> {
         let stage_info = &stage_table_info.stage_info;
         if stage_table_info.is_variant {
             let schema = Arc::new(TableSchema::new(vec![TableField::new(
@@ -88,18 +91,16 @@ impl OrcTable {
             let files_to_read = &stage_table_info.files_to_copy;
             let operator = init_stage_operator(stage_info)?;
             let first_file = match &files_to_read {
-                Some(files) => files[0].clone(),
-                None => stage_table_info
-                    .files_info
-                    .first_file(&operator)
-                    .await?
-                    .clone(),
+                Some(files) => Some(files[0].clone()),
+                None => stage_table_info.files_info.first_file(&operator).await?,
             };
 
-            let schema_from = first_file.path.clone();
+            let Some(first_file) = first_file else {
+                return ctx.get_zero_table().await;
+            };
 
+            let schema_from = first_file.path.clone();
             let arrow_schema = Self::prepare_metas(first_file, operator.clone()).await?;
-
             let table_schema = Arc::new(
                 TableSchema::try_from(arrow_schema.as_ref()).map_err(ErrorCode::from_std_error)?,
             );
diff --git a/src/query/storages/parquet/src/parquet_table/table.rs b/src/query/storages/parquet/src/parquet_table/table.rs
@@ -108,6 +108,7 @@ impl ParquetTable {
 
     #[async_backtrace::framed]
     pub async fn create(
+        ctx: &dyn TableContext,
         stage_info: StageInfo,
         files_info: StageFilesInfo,
         read_options: ParquetReadOptions,
@@ -119,13 +120,18 @@ impl ParquetTable {
     ) -> Result<Arc<dyn Table>> {
         let operator = init_stage_operator(&stage_info)?;
         let first_file = match &files_to_read {
-            Some(files) => files[0].path.clone(),
-            None => files_info.first_file(&operator).await?.path.clone(),
+            Some(files) => Some(files[0].clone()),
+            None => files_info.first_file(&operator).await?,
         };
 
+        let Some(first_file) = first_file else {
+            return ctx.get_zero_table().await;
+        };
+
+        let first_file = first_file.path;
+
         let (arrow_schema, schema_descr, compression_ratio) =
             Self::prepare_metas(&first_file, operator.clone()).await?;
-
         let schema =
             arrow_to_table_schema(&arrow_schema, case_sensitive, fmt.use_logic_type)?.into();
         let table_info = create_parquet_table_info(schema, &stage_info)?;
diff --git a/src/query/storages/system/src/lib.rs b/src/query/storages/system/src/lib.rs
@@ -67,6 +67,7 @@ mod user_functions_table;
 mod users_table;
 mod util;
 mod virtual_columns_table;
+mod zero_table;
 
 pub use backtrace_table::BacktraceTable;
 pub use build_options_table::BuildOptionsTable;
@@ -132,3 +133,4 @@ pub use user_functions_table::UserFunctionsTable;
 pub use users_table::UsersTable;
 pub use util::generate_catalog_meta;
 pub use virtual_columns_table::VirtualColumnsTable;
+pub use zero_table::ZeroTable;
diff --git a/src/query/storages/system/src/zero_table.rs b/src/query/storages/system/src/zero_table.rs
@@ -0,0 +1,90 @@
+// Copyright 2021 Datafuse Labs
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use std::sync::Arc;
+
+use databend_common_catalog::plan::PartStatistics;
+use databend_common_catalog::plan::Partitions;
+use databend_common_catalog::plan::PartitionsShuffleKind;
+use databend_common_catalog::plan::PushDownInfo;
+use databend_common_catalog::table::Table;
+use databend_common_catalog::table_context::TableContext;
+use databend_common_exception::Result;
+use databend_common_expression::types::number::UInt8Type;
+use databend_common_expression::types::NumberDataType;
+use databend_common_expression::utils::FromData;
+use databend_common_expression::BlockEntry;
+use databend_common_expression::DataBlock;
+use databend_common_expression::TableDataType;
+use databend_common_expression::TableField;
+use databend_common_expression::TableSchemaRefExt;
+use databend_common_meta_app::schema::TableIdent;
+use databend_common_meta_app::schema::TableInfo;
+use databend_common_meta_app::schema::TableMeta;
+
+use crate::SyncOneBlockSystemTable;
+use crate::SyncSystemTable;
+
+pub struct ZeroTable {
+    table_info: TableInfo,
+}
+
+impl SyncSystemTable for ZeroTable {
+    const NAME: &'static str = "system.zero";
+
+    fn get_table_info(&self) -> &TableInfo {
+        &self.table_info
+    }
+
+    fn get_full_data(&self, _ctx: Arc<dyn TableContext>) -> Result<DataBlock> {
+        Ok(DataBlock::new(
+            vec![BlockEntry::Column(UInt8Type::from_data(vec![]))],
+            0,
+        ))
+    }
+
+    fn get_partitions(
+        &self,
+        _ctx: Arc<dyn TableContext>,
+        _push_downs: Option<PushDownInfo>,
+    ) -> Result<(PartStatistics, Partitions)> {
+        Ok((
+            PartStatistics::new_exact(0, 0, 0, 0),
+            Partitions::create(PartitionsShuffleKind::Seq, vec![]),
+        ))
+    }
+}
+
+impl ZeroTable {
+    pub fn create(table_id: u64) -> Arc<dyn Table> {
+        let schema = TableSchemaRefExt::create(vec![TableField::new(
+            "dummy",
+            TableDataType::Number(NumberDataType::UInt8),
+        )]);
+
+        let table_info = TableInfo {
+            desc: "'system'.'zero'".to_string(),
+            name: "zero".to_string(),
+            ident: TableIdent::new(table_id, 0),
+            meta: TableMeta {
+                schema,
+                engine: "SystemZero".to_string(),
+                ..Default::default()
+            },
+            ..Default::default()
+        };
+
+        SyncOneBlockSystemTable::create(ZeroTable { table_info })
+    }
+}
diff --git a/tests/sqllogictests/suites/base/05_ddl/05_0016_ddl_stage.test b/tests/sqllogictests/suites/base/05_ddl/05_0016_ddl_stage.test
@@ -59,7 +59,7 @@ statement ok
 SHOW STAGES
 
 statement ok
-create stage s;
+create or replace stage s;
 
 statement ok
 create table t(c int);
@@ -73,8 +73,9 @@ copy into @s from t;
 statement ok
 create or replace stage s;
 
-statement error 1006.*no file found
+query I
 select * from @s;
+----
 
 statement ok
 DROP STAGE s;
diff --git a/tests/sqllogictests/suites/stage/formats/orc/select_orc.test b/tests/sqllogictests/suites/stage/formats/orc/select_orc.test
@@ -1,4 +1,8 @@
-query 
+query
+select * from @data/invalid_orc/alltypes.zstd.orc (file_format=>'orc')
+----
+
+query
 select boolean, int8, binary, decimal, date32 from @data/orc/alltypes.zstd.orc (file_format=>'orc')
 ----
 NULL NULL NULL NULL NULL
@@ -13,7 +17,7 @@ NULL NULL NULL NULL NULL
 0 53 F09FA494 0.99999 1900-01-01
 NULL NULL NULL NULL NULL
 
-query 
+query
 select int8 from @data/orc/alltypes.zstd.orc (file_format => 'orc') where boolean is not null;
 ----
 0
@@ -26,7 +30,7 @@ select int8 from @data/orc/alltypes.zstd.orc (file_format => 'orc') where boolea
 52
 53
 
-query 
+query
 select * from @data/orc/nested_array.orc  (file_format=>'orc')
 ----
 [1,NULL,3,43,5]
@@ -35,15 +39,15 @@ select * from @data/orc/nested_array.orc  (file_format=>'orc')
 NULL
 [3,NULL]
 
-query 
+query
 select * from @data/orc/nested_map.orc  (file_format=>'orc')
 ----
 {'zero':0,'one':1}
 NULL
 {'two':2,'tree':3}
 {'one':1,'two':2,'nill':NULL}
 
-query 
+query
 select * from @data/orc/nested_struct.orc  (file_format=>'orc')
 ----
 (1.0,1)
diff --git a/tests/sqllogictests/suites/stage/formats/parquet/infer_schema.test b/tests/sqllogictests/suites/stage/formats/parquet/infer_schema.test
@@ -1,3 +1,7 @@
+query
+select * from infer_schema(location => '@data/invalid_xxx/tuple.parquet')
+----
+
 query
 select * from infer_schema(location => '@data/parquet/tuple.parquet')
 ----
diff --git a/tests/sqllogictests/suites/stage/formats/parquet/select_parquet.test b/tests/sqllogictests/suites/stage/formats/parquet/select_parquet.test
@@ -1,4 +1,9 @@
-query 
+
+query
+select * from @data/invalid_path/alltypes_plain.parquet (pattern => '')
+----
+
+query
 select * from @data/parquet/alltypes_plain.parquet (pattern => '')
 ----
 4 1 0 0 0 0 0.0 0.0 03/01/09 0 2009-03-01 00:00:00.000000
@@ -10,7 +15,7 @@ select * from @data/parquet/alltypes_plain.parquet (pattern => '')
 0 1 0 0 0 0 0.0 0.0 01/01/09 0 2009-01-01 00:00:00.000000
 1 0 1 1 1 10 1.1 10.1 01/01/09 1 2009-01-01 00:01:00.000000
 
-query 
+query
 select id from  @data/parquet/alltypes_plain.parquet (pattern=>'') where tinyint_col = 0 order by timestamp_col limit 5
 ----
 0
@@ -24,7 +29,7 @@ drop view if exists view_parquet
 statement ok
 create view view_parquet as select * from @data/parquet/alltypes_plain.parquet  (FILE_FORMAT=>'parquet', pattern=>'')
 
-query 
+query
 select * from view_parquet
 ----
 4 1 0 0 0 0 0.0 0.0 03/01/09 0 2009-03-01 00:00:00.000000
@@ -36,7 +41,7 @@ select * from view_parquet
 0 1 0 0 0 0 0.0 0.0 01/01/09 0 2009-01-01 00:00:00.000000
 1 0 1 1 1 10 1.1 10.1 01/01/09 1 2009-01-01 00:01:00.000000
 
-query 
+query
 select id from view_parquet where tinyint_col = 0 order by timestamp_col limit 5
 ----
 0
